EP0714383A4 - Compositions optimisees et procedes de conception microstructurelle de melanges de ciment - Google Patents

Compositions optimisees et procedes de conception microstructurelle de melanges de ciment

Info

Publication number
EP0714383A4
EP0714383A4 EP94927185A EP94927185A EP0714383A4 EP 0714383 A4 EP0714383 A4 EP 0714383A4 EP 94927185 A EP94927185 A EP 94927185A EP 94927185 A EP94927185 A EP 94927185A EP 0714383 A4 EP0714383 A4 EP 0714383A4
Authority
EP
European Patent Office
Prior art keywords
mixture
cement
aggregate
slump
water
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP94927185A
Other languages
German (de)
English (en)
Other versions
EP0714383A1 (fr
Inventor
Per Just Andersen
Simon K Hodson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
E Khashoggi Industries LLC
Original Assignee
E Khashoggi Industries LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by E Khashoggi Industries LLC filed Critical E Khashoggi Industries LLC
Publication of EP0714383A1 publication Critical patent/EP0714383A1/fr
Publication of EP0714383A4 publication Critical patent/EP0714383A4/fr
Ceased legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/003Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor characterised by the choice of material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28BSHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B1/00Producing shaped prefabricated articles from the material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28BSHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B11/00Apparatus or processes for treating or working the shaped or preshaped articles
    • B28B11/24Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28BSHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B11/00Apparatus or processes for treating or working the shaped or preshaped articles
    • B28B11/24Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
    • B28B11/245Curing concrete articles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28BSHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B3/00Producing shaped articles from the material by using presses; Presses specially adapted therefor
    • B28B3/20Producing shaped articles from the material by using presses; Presses specially adapted therefor wherein the material is extruded
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28CPREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C7/00Controlling the operation of apparatus for producing mixtures of clay or cement with other substances; Supplying or proportioning the ingredients for mixing clay or cement with other substances; Discharging the mixture
    • B28C7/02Controlling the operation of the mixing
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34Auxiliary operations
    • B29C44/3402Details of processes or apparatus for reducing environmental damage or for working-up compositions comprising inert blowing agents or biodegradable components
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28Shaping operations therefor
    • B29C70/40Shaping or impregnating by compression not applied
    • B29C70/50Shaping or impregnating by compression not applied for producing articles of indefinite length, e.g. prepregs, sheet moulding compounds [SMC] or cross moulding compounds [XMC]
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B22/00Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
    • C04B22/002Water
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B40/00Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B40/00Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/0028Aspects relating to the mixing step of the mortar preparation
    • C04B40/0032Controlling the process of mixing, e.g. adding ingredients in a quantity depending on a measured or desired value
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B40/00Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/06Inhibiting the setting, e.g. mortars of the deferred action type containing water in breakable containers ; Inhibiting the action of active ingredients
    • C04B40/0608Dry ready-made mixtures, e.g. mortars at which only water or a water solution has to be added before use
    • C04B40/0616Dry ready-made mixtures, e.g. mortars at which only water or a water solution has to be added before use preformed, e.g. bandages
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B7/00Hydraulic cements
    • C04B7/36Manufacture of hydraulic cements in general
    • C04B7/48Clinker treatment
    • C04B7/52Grinding ; After-treatment of ground cement
    • C04B7/527Grinding ; After-treatment of ground cement obtaining cements characterised by fineness, e.g. by multi-modal particle size distribution
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05CAPPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C5/00Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
    • B05C5/02Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work
    • B05C5/0245Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work for applying liquid or other fluent material to a moving work of indefinite length, e.g. to a moving web
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001Combinations of extrusion moulding with other shaping operations
    • B29C48/0012Combinations of extrusion moulding with other shaping operations combined with shaping by internal pressure generated in the material, e.g. foaming
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/15Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor incorporating preformed parts or layers, e.g. extrusion moulding around inserts
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2003/00Use of starch or derivatives as moulding material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/04Condition, form or state of moulded material or of the material to be shaped cellular or porous
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29LINDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00Other particular articles
    • B29L2031/712Containers; Packaging elements or accessories, Packages
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2565/00Wrappers or flexible covers; Packaging materials of special type or form
    • B65D2565/38Packaging materials of special type or form
    • B65D2565/381Details of packaging materials of special type or form
    • B65D2565/385Details of packaging materials of special type or form especially suited for or with means facilitating recycling
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00Technologies for solid waste management
    • Y02W30/50Reuse, recycling or recovery technologies
    • Y02W30/91Use of waste materials as fillers for mortars or concrete

Definitions

  • the present invention relates to hydraulic cementitious compositions, products made from such compositions, and the methods for processing such hydraulic cementitious compositions and products. More particularly, the present invention is directed to systems and processes for optimizing the performance and design properties of cementitious materials, while minimizing manufacturing costs, through a materials science approach of microstructurally engineering the materials. Further, the present invention is directed to systems ' and processes capable of determining the appropriate modifications to the processing parameters in a specific method of manufacture in response to variations in the feedstock materials, thereby reproducibly producing a material with consistent performance characteristics and design properties.
  • Hydraulic cementitious materials were first used about two thousand years ago by the Romans as the binding agent in mortars (i.e., now typically a combination of cement, water, and sand) and concretes (i.e., now typically a combination of cement, water, and aggregates such as sand and/or rock) .
  • This knowledge of hydraulic cementitious materials was later lost and then rediscovered in 1829 by J. Aspin in England. Since 1829, concrete has had a variety of uses because it is relatively inexpensive and can be easily worked under a wide range of conditions. Importantly, the versatility of concrete is enhanced because very little training or specialized equipment is needed to manufacture traditional concrete products .
  • concrete is employed in the infrastructure of every major component of modern society, e.g., pipes, sidewalks, curbs, bridges, highways, supports, foundations, and dams.
  • Hydraulic cement-based materials are formed by mixing cement with water to form a cement paste.
  • Typical cement paste will have a water to cement ratio in the range from about 0.1 to about 1.
  • cement paste includes a fluid mixture of cement and water.
  • the synthesized clinker minerals in the cement reacts chemically with the water to form a new complex phase structure described as "CSH"-gel or calcium- silicate-hydrate.
  • CSH complex phase structure
  • concrete is broadly defined as an inorganic composite material including cement paste as a primary binder that develops its properties under "near" ambient conditions. (Concrete is distinguished from inorganic ceramic materials in that it is not heated to several hundreds of degrees to develop bonding through a sintering process, rather it is a hydrated bonding material.) Concrete is a hard, strong building material made by mixing a water-cement mixture with one or more aggregates including sand, gravel, other geologic materials, metals, and/or metallic alloys.
  • Such components may include three types of sand, three types of
  • the two most important design criteria for cementitious materials are (a) the rheological flow properties of the fresh concrete, and (b) the compressive strength of the concrete as measured 28 days after the beginning of the hardening process.
  • Flow properties of concrete are typically measured by filling a 30 cm high conical cylinder with freshly mixed concrete. The conical cylinder is then " removed, leaving the now conically shaped freshly mixed concrete, freestanding. The vertical distance that the concrete then drops or slumps corresponds to the flow property of the concrete.
  • the compressive strength of concrete is typically ascertained by the load failure of concrete cylinders cured for 28 days. Strength is measured in psi (pounds/square inch) or MPa (Megapascals) .
  • test mixtures must be made to ensure the required slump and strength are obtained.
  • the test mixtures cause considerable delay since at least 28 days for curing is required.
  • Additional testing may reveal that by varying the size, range, and proportions of sand, coarse aggregate, and cement, a less expensive mixture might be obtained that possesses the same or even closer desired properties of slump and strength.
  • Another design approach is to initially produce a variety of concrete mixtures by adding and varying different components including admixtures.
  • the admixtures can include fly ash, silica fume, water reducers, pozzolans, fillers, and air entraining agents which affect the slump and strength of the concrete.
  • the mixtures are selected from those surrounding a recommended mix design having a desired theoretical slump and strength.
  • varying a concrete mixture having 13 components on 10 different experimental levels would result in 10 13 total number of combinations.
  • Shieldstone & Associate, Inc. of Dallas, Texas, which recognize these challenges and . attempt to amass and sort large databases of mix designs for ascertaining an optimal mix design given a certain feedstock.
  • the Shieldstone system attempts to match particle size distributions of known concrete mixes with available feedstock so as to design mixes having similar properties.
  • Such programs have had minimal success and applicability as a result of the almost infinite types of components for a given location that can be used in a mix design.
  • the actual size and surface texture of the types of coarse aggregate which in turn affect the properties of the mixture, can be of almost infinite variety. Accordingly, it is extremely difficult for one having an available feedstock to match the empirical results of mixtures made from a different feedstock. The problem is compounded as the number of available components increases. Furthermore, basing a new mixture on the empirical results of a previous mixture does not improve the new mixture nor does it insure that the new mixture will be the most optimal or economical.
  • a standard concrete mixture is given a theoretical design strength based on the minimum 28-day strength of test cylinders. Depending on the number of cylinders tested and the standard deviation between test results, the actual and theoretical design strength can substantially vary. In contrast, the more consistent the concrete can be produced, the less the concrete needs to be overdesigned.
  • the quality and gradation of the available cement may vary in a range from A (worse) to B (best) .
  • the quality and gradation of each type of aggregate will also vary in a range from C to D.
  • the sand quality will vary in a range from E to F.
  • Even the quality of the water and other admixtures will vary within a given range; however, typically these will be of less importance than the cement, sand, and coarse aggregate variations .
  • the range for any given cement, sand, or aggregate material can be quite large since it is relatively expensive to obtain feedstock materials having a narrow range of consistent quality and size. It has been typically found to be more economical to significantly overdesign the concrete material rather than start with quality-controlled, guaranteed, consistent feedstocks.
  • the manufacturer when processing the concrete, the manufacturer must assume that at any given time, the quality of the sand is at "A” (its worst) , the quality of the aggregates is at “C” (its worst) , and the quality of the cement is at "E” (its worst) . It becomes immediately apparent that the types and amounts of the materials actually used must be significantly different than those necessary to achieve the desired result.
  • preestab- lished mixes typically have an excess of sand in the mixture to insure a cohesive mixture that will not bleed or segregate.
  • the addition of excess sand results in a more porous mixture that is less durable.
  • Mixtures also typically include more cement than necessary, thereby increasing the price, in order to insure that the mixture has sufficient strength.
  • a further problem encountered in the day-to-day practice of the concrete industry is that, because of the above mentioned variations in the materials' properties, the truck drivers frequently take some action to symptomatically modify or "correct" the workability or flow characteristics of the concrete from those existing at the time the concrete was placed in the truck at the ready-mix plant. It has been estimated that in approximately 70% of the deliveries of concrete in the United States the truck driver will modify the concrete specification, typically by adding water to the concrete mixture to make it "pour” or "look” better. The result is that the water to cement ratio is increased and the compressive strength is decreased. In other countries, it has been determined that this practice has such serious consequences, it is not permitted.
  • feedstocks e . g. , cement, sand, gravel, aggregates, water, and admixtures
  • feedstocks e . g. , cement, sand, gravel, aggregates, water, and admixtures
  • Another significant advancement in the art would be to provide novel processes for designing concrete such that the cementitious compositions predictably meet the required strength, slump, and durability characteristics.
  • the present invention relates to hydraulic cementitious compositions, products, and systems for manufacturing and processing such hydraulic cementitious compositions and concrete products which optimize the performance and design properties of cementitious materials, while minimizing manufacturing costs.
  • a materials science approach is utilized which offers the opportunity of microstructurally engineering the desired quality characteristics and performance properties into the cementitious materials.
  • Step 1 is ascertaining the maximum packing density of a dry concrete mixture including cement and at least one or more types of aggregate ("types" corresponds to aggregates within a certain range of sizes.
  • types corresponds to aggregates within a certain range of sizes.
  • Conventional mixtures will usually have one type of fine aggregate, e.g., sand, and one type of coarse aggregate, e.g., gravel) .
  • the proper combination of different types of aggregate will result in a concrete mixture of increased packing density and can result in a mixture having maximum packing density.
  • the proportions of cement and the different types of fine and coarse aggregates needed to obtain maximum packing density are determined by theoretically calculating the packing densities for all combinations of the feedstock. By comparing the packing densities, one can then determine the maximum packing density and the corresponding percent volume of the components.
  • Step 2 is determining the initial optimal concrete mixture that is as close to the maximum packing density as possible but has sufficient cohesion not to bleed or segregate and also has the desired strength and slump.
  • the underlying approach behind the optimization process is to first determine the unit cost of the initial mixture closest to the maximum packing density that has the desired strength, slump, and cohesion properties and then to compare it to the unit cost of mixtures with the same properties but at varied fine-to-coarse aggregate ratios. By comparing the unit cost of each of the optimal mixtures at the varying fine-to-coarse aggregate ratios, one can determine the most economical mixture with the desired properties.
  • the initial optimal mixture is determined by first selecting a mixture that is close to having maximum packing density so as to provide optimal properties but has suffi- cient sand to produce a cohesive matrix that will prevent bleeding and segregation of the concrete.
  • the packing density of the mixture and the required amount of water needed for the mixture to obtain a desired slump are then determined. With this information, the resulting strength of the mixture is calculated and compared to the desired strength. If the calculated strength is too low or too high, the percent volume of cement is increased or de ⁇ creased, respectively, keeping the fine-to-coarse aggregate ratio constant.
  • the above process is now repeated for the new mixture and the process continues until a mixture with the desired strength and slump is determined for the set fine-to-coarse aggregate ratio.
  • the resulting mixture is defined as the initial optimal mixture.
  • Step 3 compares the unit cost for the optimal mixtures at each defined fine-to-coarse aggregate ratio so as to determine the overall optimal mixture that has desired properties and minimal cost.
  • the process is most logically accomplished by determining the fine-to-coarse-aggregate ratio at the initial mixture defined in Step 2.
  • the volume of fine aggregate is then incrementally increased as the volume of coarse aggregate is decreased, respectively, thereby defining a new fine-to-coarse-aggregate ratio.
  • the composition and cost of the optimal mixture at the new fine-to-coarse-aggregate ratio is then determined and compared to the previous optimal mixture. If the new optimal mixture is less expensive, then the fine-to-coarse- aggregate ratio is again varied and an optimal composition and cost is determined and compared. This process continues until the new mixture becomes more expensive than the previous mixture (or until the maximum amount of fine aggregate is reached) at which point the previous mixture is the best mixture.
  • Steps 4 -7 calculate the effects of combining the admixtures including fly ash, silica fume, water reducers, and fillers, respectively, to the standard concrete mixture.
  • Water reducers are added to decrease the amount of water required to produce a mixture with a desired slump.
  • Fly ash and fillers are added as a replacement of cement, especially in low strength concrete, to decrease the materials costs and to decrease the amount of water required to produce a mixture with a desired slump.
  • Fly ash, silica fume, and pozzolans also have cementitious properties that independently contribute to the strength of concrete.
  • Silica fume usually increase the amount of water required to produce a mixture with a desired slump, while other pozzolans will either' decrease or increase the amount of water required depending on the chemical composition and morphology of the pozzolan.
  • Step 8 combines the previous processes into a set of embedded "do loops" that incrementally vary the components and calculate the proportions of fine aggregate, cement, coarse aggregate, mixing water, fly ash, silica fume, and water reducers that will produce a concrete mixture with desired properties and minimum cost.
  • Step 9 discusses air-entraining agents and how they are accounted for and corrected for in the optimization process so as to insure that the resulting concrete structure has a sufficient specified air content. Air entraining agents are added to introduce freeze/thaw durability into the concrete. Step 10 determines a correction factor to be applied to the optimization process so as to obtain improved estimates of the slump results. In general, this is accomplished by plotting theoretical water results versus actual water results for the same slump. The correlation between the results is then defined and incorporated into the process so as to produce improved results.
  • Step 11 determines durability or porosity of concrete which can be incorporated as a property into the optimization process. Selecting a mixture based on durability insures that the selected mix has sufficient durability for its intended use.
  • Step 12 discloses how to accurately determine what volume or weight of the components of a mixture are required to obtain a precise desired yield or volume of the final mixture. This process takes into account particle packing and the interstitial spaces between the particles. Further, the present invention is directed to systems capable of determining the appropriate modifications to the processing parameters in response to variations in the feedstock materials, thereby reproducibly producing a material with consistent performance and design properties.
  • the hydrated cement compositions of the present invention may be prepared having high density and strength. It has been observed that the processing parameters according to the present invention can be controlled so that there is little or no measurable bleeding or segregation of the fresh concrete.
  • Figure 1 is a packing density chart for the ternary mixture of cement, quartz sand (0-2mm) , and crushed granite (8-16mm) .
  • Figure 2 is the packing density chart of Figure 1 with lines designating how to read a composition corresponding to a density within the chart.
  • Figure 3 is a graph of experimental packing densities versus theoretical packing densities (using the Toufar model) of a ternary mixture of cement, pea gravel (3/8") , and sand.
  • Figure 4 is a graph comparing the experimental packing densities versus the corrected theoretical packing densities of the mixture plotted in Figure 3.
  • Figure 5 is a graph of a packing density chart showing pseudo particle lines.
  • Figure 6 is a graph of experimental strengths for mixtures versus the corresponding theoretical strengths for the mixture using the Feret equation.
  • Figure 7 is a graph comparing the experimental strengths versus the theoretical strengths of the mixtures in Figure 6.
  • Figures 8 (A) - (B) comprise a logic flow diagram of the optimization system.
  • Figure 9 is a tree of the logic flow diagram shown in Figure 8 (B) .
  • Figure 10 shows the correlation between the corrected theoretical packing density and the experimental packing density of the sand and pea gravel in Example 1.
  • Figure 11 shows the correlation between the corrected theoretical ternary packing density and the experimental ternary packing density of the cement, sand, and pea gravel of Example 1.
  • Figure 12 shows the correlation between the actual amount of water and the theoretical amount for the mixtures in Example 1.
  • Figure 13 shows the correlation between the air content and slump for the mixtures in Example 1.
  • Figure 14 shows the correlation between the actual slump and the designed slump for the mixtures in Example 1.
  • Figure 15 shows the correlation between the actual amount of water and the theoretical amount for the mixtures in Example 2.
  • Figure 16 shows the correlation between the air content and slump for the mixtures in Example 2.
  • Figure 17 shows the correlation between the actual slump and the designed slump for the mixtures in Example 2.
  • Figure 18 shows the correlation between the actual amount of water and the theoretical amount for the mixtures in Example 3.
  • Figure 19 shows the correlation between the air content and slump for the mixtures in Example 3.
  • Figure 20 shows the correlation between the .actual slump and the designed slump for the mixtures in Example 3.
  • Figure 21 shows the correlation between the actual amount of water and the theoretical amount for the mixtures in Example 4.
  • Figure 22 shows the correlation between the air content and slump for the mixtures in Example 4.
  • Figure 23 shows the correlation between the actual slump and the designed slump for the mixtures in Example 4.
  • Figure 24 shows the correlation between the actual amount of water and the theoretical amount for the mixtures in Example 6.
  • Figure 25 shows the correlation between the air content and slump for the mixtures in Example 6.
  • Figure 26 shows the correlation between the actual slump and the designed slump for the mixtures in Example 6.
  • Figure 27 shows the packing density for the pea gravel of Example 18.
  • Figure 28 shows the average diameter of the pea gravel in Example 18.
  • Figure 29 shows the packing density for the sand in Example 19.
  • Figure 30 shows the average diameter of the sand in Example 19.
  • Figure 31 shows the packing density for a typical 1" rock of Example 20.
  • Figure 32 shows the average diameter of a typical 1" rock in Example 20.
  • Figure 33 is a packing density chart for three coarse aggregates of Example 32.
  • the present invention relates to hydraulic cementitious compositions, products, and the methods for manufacturing and processing such hydraulic cement and concrete products. More particularly, the present invention is directed to creating systems to optimize the performance and design properties of cementitious mixtures, while minimizing manufacturing and compositional costs, through a materials science approach of microstructurally engineering the materials. Further, the present invention is directed to systems capable of determining the appropriate modifications to the processing parameters in response to variations in the feedstock materials, thereby reproducible producing a material with consistent performance and design properties.
  • the current invention uses a materials science approach to microstructurally engineer concrete so that it possesses the desired characteristics and qualities.
  • models have been developed and combined with those known in the art to produce new models that accurately determine the strength, slump, and durability of a concrete mixture based on the composition of the mix design.
  • the models can also be used to determine whether admixtures such as fillers, water reducers, air entraining agents, silica fume, fly ash, and other pozzolans should be added and, if so, in what quantity to optimize the design mixture.
  • Microstructural engineering is the process of building into the microstructure of cementitious compositions certain desired, predetermined properties such that the properties are reflected in the final product.
  • the microstructural engineering approach is also cognizant of costs and manufacturing variations and complications.
  • the microstructural engineering analysis ap- proach, in contrast to the traditional trial-and-error mix and test approach, allows one to design and predict desired properties such as strength, weight, slump/workability, porosity, permeability, durability, cost, environmental concerns, and manufacturing problems.
  • the number of different raw- materials available to engineer a specific product is enormous, with estimates ranging from between fifty thousand and eighty thousand. They can be drawn from such disparately broad classes as metals, polymers, elastomers, ceramics, glasses, composites, and cements.
  • Ceramics for instance, have high moduli, while polymers have low moduli; metals can be shaped by casting and forging, while composites require lay-up or special molding techniques.
  • Compartmentalizing materials however, has its dangers; it can lead to specialization (the metallurgist who knows nothing of ceramics) and to conservative thinking
  • cementitious materials have such a wide utility and can be designed and microstructurally engineered, then their applicability to a variety of possible products becomes innumerable.
  • the present invention uses the strategy of microstructurally engineering concrete to develop raw cementitious materials with highly-controlled properties.
  • the approach is based on materials science which is a discipline, or a scientific approach, that focuses on relationships between new materials, processing, microstructure, and performance properties, as shown in Table I listed below.
  • Empirical models were then created to describe how processing of the materials affected the microstructure and thus ' performance properties of the resulting cement product.
  • the empirical models were refined ( e . g. , expanded and narrowed in scope and limited by defined constants) to create models that could then be tested.
  • Valid models were then combined to make a total system for the design and production of specific products having desired properties.
  • the resulting system disclosed by the current invention can perform several functions. Most notably, the ability to predictably determine the relationship between each component and step previously outlined allows for superior low-cost concrete to be designed and produced. More specifically, the system can determine what combina ⁇ tion of materials, including admixtures, should be used to obtain a cement mixture with a desired slump and resulting strength that will have a minimal cost . The system can also determine what combination of available materials should be used to obtain a mixture with desired properties. Furthermore, the system can define what combination of materials should be used to obtain a mixture that will have maximum durability or any desired durability without segregation or bleeding. Additional functions of the system will be disclosed or be self-apparent in the specification and claims.
  • the present system has been formulated into a series of steps that can be calculated manually, with the assistance of some diagrams, or can be formulated into a computer program.
  • the formulation process requires the user to input the desired strength and slump; the natural packing density and average particle diameter of the aggregate and cement used; whether fly ash, silica fume, fillers, water reducers, air entraining agents, or other pozzolans are to be used and if so with what characteristics; and the unit price for each component in the concrete.
  • the process determines the mix designs that will result in a concrete having the desired properties.
  • the unit prices of these mix designs are then calculated and compared so as to determine the least expensive concrete mixture having the desired properties.
  • wet properties include slump, which is a particular measure of the rheological function of the water and the cement content.
  • the more water added to a concrete mixture the lower the viscosity of the cement paste and the lower the friction force between the aggregate particles -- therefore, the higher the slump.
  • high slump leads to increased workability which makes it easier to place and finish the concrete.
  • different slumps ranging from 0 to 23 cm are required for different kinds of structures.
  • the dry properties include strength and porosity properties. These properties are also a function of the water content, but in opposite proportions. The more water added to a cement mixture, the lower the concentration of cement, the'reby resulting in lower ultimate strength of the concrete. Furthermore, mixtures with high water contents often segregate or bleed. "Bleeding" is the migration of water to the surface layer of newly mixed concrete as a result of the settling of the aggregate. The migration of water further increases the water-cement ratio at the surface layer of the concrete, thereby decreasing the strength and durability of the surface layer.
  • “Segregation” is the separation of mortar (cement, water, and sand) from the coarse aggregates leading to decreased homogeneity, areas of less cement, and hence, reduced - strength and increased porosity and permeability. Finally, a high water content also increases porosity throughout the cured concrete, thereby decreasing its durability.
  • Packing density is a function of particle packing which is the process of selecting appropriate sizes and proportions of particulate materials to fill larger voids with smaller particles, containing smaller voids that again are filled with smaller particles, and so on to achieve maximum particle density.
  • a concrete can be designed by packing the coarse aggregate as efficiently as possible, then packing the fine aggregate into the interstitial spaces, and finally filling the remaining smaller interstitial spaces with paste.
  • the new mixture has a smaller total volume of 0.625 cubic meters because the volume of air voids inside the mixture are decreased to 0.125 cubic meters. Accordingly, when the same quantity of water, X, is added to the new mixture having a density of 0.8, the slump is increased because the water that was initially used to fill the air voids is now used to surround the particles and decrease their friction force.
  • cement is generally the most expensive element in a concrete mixture.
  • sufficient cement must be added to coat all aggregates and to preferably fill the voids within the concrete mixture. (A higher strength is obtained by filling the voids between the aggregates with cement as opposed to just water.)
  • the surface area of the particles and the voids between the particles are minimized, thus, minimizing the amount of cement needed. Accordingly, the cost of the concrete is also minimized.
  • determining what mixture is the least expensive depends on the cost of the different components . At times, mixtures having a lower packing density may be less expensive. For example, sand is often the least expensive component .
  • mixtures having a low concentration of cement and a high concentration of sand may be the least expensive mixture.
  • percent of sand increases, so as to move away from the point of maximum packing density, the porosity increases, thereby decreasing the durability of the mixture.
  • System rheology refers in part to the viscosity and yield stress of a mixture and is a function of both macro-rheology and micro-rheology.
  • the macro-rheology is the relationship of the solid particles with respect to each other as defined by the particle packing. That is, by selectively regulating the particle size distribution of a mixture while holding the water or lubricating component constant, the yield stress and viscosity of the mixture can be selectively controlled.
  • Control over the system rheology of a mixture is important in the economic mass production of thin-walled container and particles such as those disclosed in the patent application entitled "Hydraulically Settable Containers and Other Articles for Storing, Dispensing, and Packaging Food and Beverages and Methods For Their Manufacture” that was previously incorporated by reference.
  • Mixtures having a low viscosity are more easily fashioned into a desired shape and thus are usually preferred during the forming step of a container.
  • the mixture once the container is formed, it is preferred that the mixture have a sufficient high yield stress to permit the container to be form stable in a self-supporting posture, thereby permitting mass production of the containers. Control over particle packing can be used in optimizing the viscosity and yield stress of a mixture.
  • the micro-rheology is a function of the lubricant fraction of the system that fills or more than fills the spaces between the "macro" particles.
  • the lubricants which may be water, rheology-modifying agents, plasticizer, or other materials
  • the micro- rheology can also be modified physically by changing the shape and size of the particles e.g. , the use of chopped fibers, plate-like mica, round-shaped silica fume, or crushed rough cement particles will interact with the lubricants differently.
  • the theory of particle packing is understood, the difficulty is in determining with speed, accuracy, and consistency what size and proportions of defined components will result in a maximum packing density.
  • the present invention resolves this problem by defining a model that accurately determines the packing density for a defined percent volume mixture of at least one type of aggregate, and cement. To determine the maximum packing density, the packing density is calculated for all percent volume combinations of the feedstock. II. Design Optimization Process
  • Step 1 discusses the process for ascertaining the maximum packing density and corresponding composition of a dry concrete mixture having cement and one or more types of aggregate.
  • Step 2 discusses the process for determining the initial optimal concrete mixture that is closest to the maximum packing density and has the desired strength, slump, and cohesion at a specific fine-to-coarse-aggregate ratio.
  • Step 3 discusses the process for comparing the unit cost for each optimal mixture at defined fine-to-coarse- aggregate ratios so as to determine the overall optimal mixture.
  • Steps 4-7 discuss the processes for calculating the effects of combining different admixtures including fly ash, silica fume, water reducers, and fillers, respec- tively, independently to the standard concrete mixture.
  • Step 8 outlines the flow diagram and iterative loops used in determining the best optimal mixture having desired properties and minimal cost.
  • the mixture includes fine aggregate, cement, coarse aggregate, mixing water, fly ash, water reducers, air entraining agents, silica fume, and pozzolans with desired properties and minimum cost.
  • Step 9 modifies the resulting mixture to insure that it reflects the proper concentration of air-entraining agent so as to have the proper air content .
  • Step 10 describes how to determine a correction factor to be applied to the optimization process so as to obtain improved slump results thereby, further optimizing the results .
  • Step 11 provides a means for determining the durabilityi ⁇ ty of a mixture to insure that the selected mixture has sufficient durability for its intended use.
  • Step 12 discloses how to accurately determine what volume or weight of the various components of a mixture are needed to produce a desired yield of the mixture.
  • the first step in the optimization process is deter ⁇ mining the maximum packing density and corresponding volume for each component in a dry concrete mixture.
  • cementitious mixture and “mixture” as used in the specification and appended claims are intended to include a composition having at least one type of cement and at least one type of aggregate and to which may be added water and various admixtures.
  • mortar as used in the specification and appended claims is intended to include a mixture having only cement and one type of aggregate.
  • Other mixtures which can be formed from the present invention include plaster and wall board.
  • aggregate or “aggregates” as used in the specification and appended claims are intended to include a variety of crushed and naturally occurring rock and mineral. For use in the present invention, however, they should be sound and conform to certain standards for optimum engineering use: they should be clean, hard, dense, strong, durable particles free of absorbed chemicals, coatings of clay, humus, and other fine material that could affect hydration and bond of the cement paste. In some mix designs it may be desirable to add aggre ⁇ gates that decrease weight or increase the insulation ability of the mixture.
  • useful aggregates include perlite, vermiculite, sand, gravel, rock, limestone, sandstone, glass beads, aerogels, xerogels, seagel, mica, clay, synthetic clay, alumina, silica, fly ash, silica fume, tabular alumina, kaolin, microspheres, hollow glass spheres, porous ceramic spheres, gypsum dihydrate, calcium carbonate, calcium aluminate, cork, seeds, lightweight polymers, xonotlite (a crystalline calcium silicate gel) , lightweight expanded clays, unreacted cement particles, pumice, exfoliated rock, and other geologic materials. Reacted and unreacted cement particles may also be considered to be "aggregates" in the broadest sense of the term.
  • the term "aggregate” will often be defined in terms of a fine aggregate and a coarse aggregate. To obtain an improved packing density it is desirable that the ratio of the average particle size of the coarse to fine aggregate be about 3:1, with about 5:1 being preferred, and about 7:1 being most preferred.
  • sand is used as a fine aggregate.
  • Sand includes compositions of particles that have diameters ranging from about 8 mm and smaller.
  • Conventional coarse aggregate usually includes compositions of particles that have diameters ranging from about 2 mm to about 165 mm. In the embodiments where thin-walled articles are being formed, it may be preferable that the aggregate size be less than twenty times the cement particle size. Such aggregate is generally less than 2mm in diameter.
  • fine aggregate and coarse aggregate as used in the specification and appended claims are not intended to be limited by any size range but are simply used to designate that one type of aggregate is larger than another.
  • coarse aggregate in a cement mixture containing two types of sand, the sand with the larger diameter would be referred to as the coarse aggregate.
  • type as used in the specification and appended claims with regard to aggregate, cement, and other solid particles is intended to include both the kind of material used and the ranges of the particle sizes.
  • coarse aggregate usually includes particles having a range from 2 mm to 165 mm
  • one type of coarse aggregate may have a particle size range from 2 mm to 8 mm while a second type may have a particle size range from 8 mm to 16 mm.
  • optimal particle packing of a mixture can be obtained by selectively combining different types of aggregates. Studies have found that types of aggregates have a defined average particle size but a large gradation will usually have improved packing.
  • the cement used in the present invention comes from the family of cements known as hydraulic cements.' Hydraulic cement is characterized by the hydration products that form upon reaction with water. Hydraulic cements are to be distinguished from other cements such as polymeric organic cements.
  • powdered hydraulic cement includes clinker, crushed, ground, and milled clinker in various stages of pulverizing and in various particle sizes.
  • hydraulic cements examples include: the broad family of portland cements (including ordinary portland cement without gypsum) , calcium aluminate cements (including calcium aluminate cements without set regulators) , plasters, silicate cements (including ⁇ - dicalcium silicates, tricalcium silicates, and mixtures thereof) , gypsum cements, phosphate cements, and magnesium oxychloride cements.
  • the term hydraulic cement also includes other cements, such as ⁇ -dicalcium silicate, which can be made hydraulic under hydrating conditions within the scope of the present invention.
  • cement is also intended to include fillers, fly ash, silica fume and other pozzolans. Hydraulic cements generally have particle sizes ranging from 0.1 ⁇ m to 100 ⁇ m.
  • total solids as used in the specification and appended claims is intended to include cement, aggregate, and, where relevant, fillers, fly ash, silica fume, and other pozzolans. Accordingly, the volume of aggregate and cement in a standard mixture always add up to 1.0.
  • the volume measurements of water and air in the mixture are also based on a fraction of the volume of total solids. Thus, a value of 0.3 for a volume of water in a mixture corresponds to a volume of water equal to 30% of the total volume of solids in a mixture. Accordingly, the total volume of the mixture including the water would be 1.3.
  • the types of aggregate and cement of the present invention are further defined by the average diameter size (d 1 ) and the natural packing density ( ⁇ ) of the types of particles. These values are experimentally determined and are necessary for calculating the theoretical packing density of the resulting concrete mixture.
  • the average diameter size is determined by plotting the particle size distribution of each material according to the Rosin- Rammler-Sperling-Bennett distribution described by the equation:
  • d is the particle diameter
  • R(D) is the cumulative probability that the diameter is less than d
  • n is the slope of the line defined by plotting the percent of particles retained on a sieve versus the sieve size.
  • the packing density of each type of material, ⁇ is determined by filling the material into a cylinder having a diameter of at least 10 times the largest particle diameter of the material . The cylinder is then tapped against a hard surface until the material is fully compacted. By reading the height of compacted material in the cylinder and the weight of material, the packing density is calculated according to the formula:
  • W M weight of the material
  • FIG. 1 is a packing density chart for the ternary mixture of cement, quartz sand (0-2 mm) , and crushed granite (8-16 mm) .
  • Side (A) of the chart defines the volume percent of fine aggregate (sand) ;
  • side (B) defines the volume percent of cement;
  • the bottom or side (C) defines the volume percent of coarse aggregate
  • the packing density values within the chart are evaluated from the Toufar, Klose, and Born model (hereinafter "Toufar model") used in connection with a correction factor.
  • the Toufar model is a formula for calculating the packing densities of binary mixtures:
  • P r 0 . 9940 P ⁇ - 0 . 00895 ( 4 )
  • the variable P c designates the corrected packing density and P ⁇ designates the theoretical or modeled packing density obtained by the Toufar model. Accordingly, by inputing values obtained from the Toufar model in for P ⁇ and solving for P c , one obtains a corrected theoretical packing density value of the concrete mixture within 2% of the actual packing density.
  • the composition of the mixture includes only coarse aggregate and fine aggregate, no cement is added.
  • the corresponding composition for the packing density on line (C) where the percent volume of coarse aggregate reads 50% is: 50% coarse aggregate, 50% fine aggregate, and 0% cement.
  • the packing density along line (C) is first calculated by varying the mixtures of coarse aggregate and fine aggregate at 1% increments.
  • is initially determined using the Toufar model (equation (3)) where r is 0.01 representing 1% volume fine aggregate, r 2 is 0.99 representing 99% volume coarse aggregate, d x is the experimentally predetermined value of d' for the fine aggregate, d 2 is the experimentally predetermined value of d' for the coarse aggregate, x is the experimentally predetermined value of ⁇ for the fine aggregate, and ⁇ 2 is the experimentally predetermined value of ⁇ for the coarse aggregate.
  • a morter is a binary mixture comprising a cement and one type of aggregate.
  • line (A) to represent the percent volume cement
  • line (C) to represent the percent volume of aggregate and then inputing incrementally varied amounts of cement and aggregate into the Toufar model.
  • all possible packing density value for the binary mixture can be defined along line (C) .
  • the highest packing density value on line (C) then corresponds to the composition of the defined cement and aggregate having the maximum packing density.
  • the Toufar model is used to calculate the values within the triangle. Since the Toufar model can only calculate packing densities for binary mixtures, pseudo-particles are defined that represent the combination of various ratios of fine aggregate to coarse aggregate along the base line. Packing densities within the triangle can then be calculated by using the pseudo- particle and cement as the binary mixture.
  • Each mixture of the pseudo-particles and cement is represented by a pseudo-particle line drawn inside the triangle.
  • Figure 5 shows a series of pseudo-particle lines 26 extending from an apex 28 of the triangle to a percent volume of coarse aggregate on line (C) . Since the percent volume of coarse aggregate ranges from 0% to 100%, there are 100 individual pseudo-particle lines.
  • Each line represents a pseudo-particle having a ratio of fine-to- coarse-aggregate defined by the intersecting coarse aggregate value. For example, the line connected to the 1% coarse aggregate value represents a pseudo-particle having a ratio of 1% coarse aggregate and 99% fine aggregate.
  • the percent volume of cement increases and the percent volume of the pseudo-particle decreases proportionally; however, the ratio of fine aggregate to coarse aggregates remains constant .
  • the packing density chart is then completed by calcu- lating and plotting the packing density for each 1% increase in the percent volume of cement along each of the pseudo-particle lines. These positions are best located on the packing density chart by drawing a horizontal line 30
  • each percent volume cement such that each horizontal line 30 intersects with each pseudo-particle line 26.
  • the intersecting points 32 are the positions at which the packing densities are calculated. The values necessary to determine the packing densities from the Toufar model can be ascertained using the previously discussed method for reading the packing density chart .
  • the first pseudo-particle line is drawn from the apex of the triangle to the point representing 1% volume coarse aggregate on line (C) .
  • the packing density is then determined on the pseudo-particle line where there is a 1% volume of cement.
  • the Toufar model is used to calculate the packing density, where r x is the percent volume of the smaller particle (cement) and equals 0.01; r 2 is the percent volume of the pseudo-particle 0.99; ⁇ p ⁇ is the experimentally predetermined packing density of the cement; ⁇ 2 is the packing density of the pseudo-particle and equals the previously corrected and calculated packing density for a mixture of 1% coarse aggregate and 99% fine aggregate; d ⁇ equals the experimentally predetermined d' value for the cement; and finally, d 2 equals the average particle diameter of the pseudo-particle.
  • x x and r 2 equal the volume of fine aggregate and coarse aggregate, respectively, in the mixture for which the packing density is being determined.
  • the values of 1 and r 2 are determined by simply reading the values from the packing density chart as previously discussed.
  • the values for d x ' and d 2 ' represent the experimentally predetermined values for d' of the fine aggregate and the coarse aggregate, respectively.
  • contour lines inside the triangle can be made by connecting those points where the packing density is the same.
  • the maximum density and corresponding percent volume mixture can then be determined by locating the highest packing density on the chart and reading the corresponding mixture as previously discussed.
  • the procedure is to use the Toufar model to produce a pseudo-particle having a packing density and average diameter size that represents both of the types of fine aggregate or coarse aggregate.
  • the pseudo-particle can then be used as the fine aggregate or coarse aggregate component in the previously discussed method for determining the maximum packing density of a ternary mixture.
  • the packing density of the pseudo-particle corresponds to the maximum packing density of the two fine aggregates or coarse aggregates.
  • the maximum packing density is determined by comparing all packing densities for the various percent volume ratios of the two components. This is the same process used to determine the packing densities of the fine aggregate and coarse aggregate along line (C) of the packing density chart.
  • the average diameter, d p ', of the pseudo-particle is obtained using the formula:
  • r x and r 2 correspond to the percent volume of the two types of coarse aggregate or fine aggregate for the mixture at maximum packing density
  • the values for d ⁇ ' and d 2 ' correspond to the average diameter of the two types of fine aggregate or coarse aggregate, respectively.
  • a pseudo-particle having a packing density and average diameter can be used to represent the various types of fine aggregate or coarse aggregate.
  • the packing density of the pseudo-particle corresponds to the maximum packing density of the ternary mixture of the fine aggregates or coarse aggregates and is determined in the same process used to calculate the maximum packing density for the ternary mixture of cement, fine aggregate, and coarse aggregate.
  • the r values correspond to the percent volume of each of the types of fine aggregate or coarse aggregate in the mixture having maximum packing density and the d p ' values correspond to the average diameter sizes of each of the types of fine aggregate and coarse aggregate, respectively.
  • the approach is to first define the packing density and average diameter size of a pseudo-particle that represents the two coarsest materials. The pseudo-particle is then combined with the next finer particle creating a binary packing which is again defined by a new pseudo-particle having a new packing density and average diameter size. The new pseudo-particle is then combined with next finer particle and the process continues until one pseudo-particle is defined to represent all of the different types of coarse aggregate or fine aggregate.
  • two or more types of cement may also be added to a mixture.
  • the particle size of the cement is so small, however, that the combination of different types of cement generally does not significantly affect the packing density of the mixture. Nevertheless, in some situations, such as powder packing or finely divided mortars, .the combination of types of cements may be relevant. In these situations, the types of cement can be represented as a pseudo-particle in the same manner as for fine aggregate and coarse aggregate.
  • the above described process teaches a method for determining the packing density for all possible combinations of a given feedstock. One is thus able, through a comparison process, to determine what components result in a maximum packing density. By varying the types of feedstock entered into the process over a large range of materials, a database can be obtained which permits one to select the types of components that will give the highest maximum packing density.
  • Step 2 Property Optimization
  • the second step in the optimization process is to determine the optimal concrete mixture that has desired strength and slump properties for a specific fine-to- coarse-aggregate ratio. Almost any fine-to-coarse- aggregate ratio can obtain a desired strength and slump by adding sufficient cement and water.
  • the present invention provides a method for determining the minimum amount of cement and water to be added to a specified fine- to-coarse-aggregate ratio to produce a concrete mixture with desired properties.
  • the present invention can be used to calculate the least expensive mixture by calculating and comparing the unit cost for each mixture at varying fine-to-coarse-aggregate ratios.
  • the current step describes how the optimal design mixture is determined for a specific fine-to-coarse-aggregate ratio.
  • Step 3 describes how the cost for each optimal mixture at varying fine-to-coarse-aggregate ratios are compared.
  • the composition of the concrete mixture having desired strength and slump properties is determined by first ascer ⁇ taining the amount of water needed to produce the desired slump in a preselected mixture. Once the amount of water is known, the resulting strength of the concrete can be obtained.
  • the resulting strength is lower or higher than the desired strength, an estimate of the amount of cement needed to obtain the desired strength is obtained, thereby producing a new mixture.
  • the amount of water needed to produce the desired slump in the new mixture is then determined and the process is repeated until the desired strength corresponds to the theoretical strength. By this process, only the minimal amount of cement needed .to obtain the desired strength is used, thereby minimizing the cost of the concrete.
  • An initial mixture that is sufficiently close to the maximum packing density to optimize concrete proper- ties without segregating or bleeding is selected by first, as discussed in Step 1, locating the maximum packing density on the packing density chart and the corresponding volume composition.
  • the volume of the corresponding cement, fine aggregate, and coarse aggregate at the point of maximum packing are respectively defined by the vari ⁇ ables V C(MP) , V F(MP , , and V ⁇ p, which add up to 1.0.
  • the volume of cement is held constant while the volume of fine aggregate is increased by a quantity defined as the cohesion safety factor, and the volume of coarse aggregate is decreased by the same quantity.
  • the mixture is thus moved horizontally left on the packing density chart.
  • the corresponding mixture is defined as the initial mixture.
  • volume of the components in the initial mixture are defined by the equations:
  • V c V C(MP) (8)
  • V F V F(MP) + CF (9)
  • V CA V ⁇ (MP
  • the variable CF represents the cohesion safety factor and is typically about 0.05.
  • the cohesion safety factor insures that the mixture has sufficient fine aggregate to make a cohesive mixture that will not segregate or bleed. Mixtures to the right of the initial mixture on the packing density chart will typically segregate or bleed.
  • the cohesion safety factor can vary in a range between about 0 to about 0.15 depending on the type of concrete. A low strength concrete requires a high cohesion factor up to about 0.15, while a high strength concrete requires a low cohesion factor of less than about 0.5.
  • the fine-to-coarse-aggregate ratio of the initial mixture is defined by a pseudo-particle line extending from the apex of the packing density chart, through the position of the initial mixture, and to the coarse aggregate line. The remainder of this step will discuss how to ascertain the optimal concrete mixture along this defined pseudo- particle line. 2 (b) .
  • the packing density of the composition of the initial concrete mixture is determined as described in Step 1.
  • the amount of mixing water required to provide the initial concrete mixture with a predetermined desired slump is ascertained. Determining this amount of water is a two-step process. First, the amount of water needed to provide the mixture with a 1 cm slump is determined using the following formula:
  • the packing density of the mixture, as defined in Step 2 (b) .
  • W- L the volume of water required to give the mixture a 1 cm slump.
  • VI 1 is a fraction of the volume of the solids in the mixture.
  • equation (11) is typically most accurate for determining the amount of water required to give a mixture a 1 cm slump.
  • the actual slump has been found to vary up to about 2.5 cm, the designation of a 1 cm slump is not critical since Step 9 of the present invention corrects for discrepancies between the amount of water added and the actual slump.
  • W x the volume of water needed for a 1.0 cm slump as previously defined
  • W 2 the volume of water needed to give the mixture a desired slump, .
  • Feret 's constant is not a true constant but depends on the type of mixing apparatus being used.
  • the constant has been found to typically be in the range from about 250-600.
  • the constant typically has been found to have a value of 280; for a counter rotational mixer, typically about 340; and for a high shear mixer, about 340-450.
  • High shear energy mixers and their methods of use are described in United States Patent No. 4,225,247 entitled "Mixing and Agitating Device" and United States Patent No.
  • K K for a given mixer
  • V A the volume of air in the mixture and is defined by the following equation:
  • %AIR estimated percent volume of air in the mixture.
  • the volume of air in a mixture varies based on the type of mixer used, the volume of fine aggregate in a mixture, and the types of admixtures combined with the mixture.
  • the percent volume of air can be estimated by those skilled in the art and is generally between about 1% to 2% for a slump greater than 10 cm and between about 2% to 4% for slump less than 10 cm.
  • Figure 6 shows a comparison of the 28 day compressive strength of a concrete mixture estimated with Feret ' s equation and the actual 28 day compressive strength of the concrete. As seen from Figure 6, the best fit line does not follow the line of direct proportionality. Using the correlation between the theoretically calculated strength and the experimental or actual strength a more precise estimation of the strength can be obtained using the following correction equation:
  • correction equation (15) are based in part on experimental strength results and, thus, may vary depending on the number and accuracy of the tests. Furthermore, equation (13) for 28-day strength is based on the assumption that the coarse aggregate and fine aggregate have a higher strength than the cured cement paste, which is generally true using sound aggregate. An exception to this would be the use of limestone which is a very weak aggregate.
  • Feret' s equation also assumes the use of standard or normal mixing, placing, finishing, and curing of the concrete as defined by the American Concrete Institute in Guide for Measuring, Mixing. Transporting, and Placing
  • ACI 304-85 ACI Committee 304 Report, (American Concrete Institute, 1985) ; and Standard Practice for Curing Concrete.
  • ACI 308-81 ACI Committee 308 Report, (American Concrete Institute revised 1986) , which are incorporated herein by specific reference.
  • Steps 2 (b) - 2 (e) are repeated by replacing the initial mixture with a new mixture and corresponding new packing density.
  • the composition of the new mixture is obtained by increasing or decreasing the volume of cement in order to obtain the desired strength.
  • An estimate of the volume of cement needed to obtain the desired strength is determined by inputing the desired strength into Feret ' s equation and solving for the corresponding volume of cement according to the following equation:
  • V C(N) volume of cement in the new mixture
  • W 2 volume of water needed to obtain the desired slump in the initial or previous mixture
  • %AIR estimated percent volume of air in the mixture
  • ⁇ D the desired strength in MPa.
  • the volume of fine aggregate and coarse aggregate must be normalized so that the volume of fine aggregate, coarse aggregate, and cement sum up to 1.0.
  • the ratio of fine-to-coarse-aggregate remains constant. Accordingly, the volume of fine aggregate and coarse aggregate in the new mixture are defined by the equations:
  • V F(N) r F • (1-V C(N) ) (17)
  • r F and r ffl are the ratios of fine aggregate and coarse aggregate, respectively, and are constants for each pseudo- particle line.
  • This new mixture corresponds to the position on the packing density chart defined by the intersection of the pseudo-particle line described in step 2 (a) and a horizon ⁇ tal line extending from new volume of cement determined by equation (16) .
  • Steps 2 (b) -2 (d) are continually repeated until the theoretical strength of the mixture equals the desired strength.
  • the resulting mixture for the defined fine-to-coarse-aggregate ratio has the desired slump and strength using a minimal amount of cement and water. Typically, the desired mixture is found within ten iterations.
  • the necessary volume of cement may be very low.
  • the mixture should generally comprise at least about 10% cement by volume. Accordingly, the volume cement can only be decreased until the obtained strength equals the desired strength or the volume cement is equal to 10%. As will be discussed below, however, the volume of cement can be less than 10% when fillers are used.
  • the above process can also be used for a morter by simply replacing the values used for the fine-to-coarse aggregate with the corresponding values for the defined aggregate in the morter.
  • the resulting composition of the cement aggregate and water produces a morter with a desired slump and strength using a minimal amount of cement . It is also assumed that the resulting morter mixture will be cost optimized. Although mixtures having an increase in the percent volume of cement and a decrease in percent volume coarse aggregate can be formed having the desired slump and at least the desired strength, such mixtures are seldom, if ever, less expensive due to the relatively high cost of cement .
  • Step 3 Cost Optimization
  • this step describes the method for determining and comparing the unit cost of the optimal concrete mixture for each fine-to-coarse-aggregate ratio so as to determine the most overall cost efficient mixture. In general, this is accomplished by first calculating the unit cost of the initial optimal mixture determined in Step 2. An optimal composition and resulting unit price is then determined for a second optimal mixture defined by a new fine-to-coarse-aggregate ratio.
  • the new fine-to-coarse-aggregate ratio is obtained by decreasing the percent volume of coarse aggregate by 1% and increasing the percent volume of fine aggregate respectively.
  • the unit price of the second optimal mixture is then compared with the unit price initial mixture. If the price of the initial mixture is less than the price of the second mixture, the composition of the initial mixture is the most economical and the process is over. If the second mixture is less than the price of the initial mixture, the fine-to-coarse-aggregate ratio is again varied so as to obtain a third optimal mixture. The cost comparison is then repeated until the least expensive mixture is obtained. More specifically, cost optimization has the following steps :
  • Step 3 (a) . Determine the unit cost for the resulting optimal mixture of Step 2 based on the unit cost of the cement, fine aggregate, and coarse aggregate used in the mixture.
  • Step 2 Using the same packing density chart as for Step 2, define a new fine-to-coarse-aggregate ratio by decreasing the volume of coarse aggregate by 0.01 and increasing the volume of fine aggregate by 0.01.
  • This new fine-to-coarse-aggregate ratio can be defined by a pseudo- particle line connecting the apex of the triangle and the value for the percent volume coarse aggregate 1% less or left of the initial mixture.
  • 3 (c) Repeat Step 2 along the new pseudo-particle line until the optimal mixture for the new fine-to-coarse- aggregate ratio is determined. This is referred to as the second optimal mixture.
  • the initial mixture used on the new pseudo-particle line has a volume of cement equal to the optimal mixture on the previous pseudo-particle line.
  • Step 3 (d) Ascertain the unit price for the second optimal mixture determined in Step 3 (c) . If the unit price of the second optimal mixture is more than the unit price of the initial optimal mixture, the initial optimal mixture is the most economical mixture, and the process is over. If the price of the second optimal mixture is less than the price of the initial optimal mixture, the fine-to-coarse- aggregate ratio is again varied as discussed in Step 3 (b) , and a third optimal mixture is obtained according to Steps 2 (b) -2 (e) . The cost of the third optimal mixture is then compared to the previous or in this case the second optimal mixture to determine which is the least expensive. The process is continued until the most economical composi ⁇ tion is determined or the maximum percent volume of fine aggregate is reached.
  • the percent volume of sand in a mixture should not be greater than about 80% for concrete even if such a compositions would be less expensive. This is because as one moves farther left on the packing density chart by increasing the volume of fine aggregate or sand, the porosity in the resulting concrete increases, thus, decreasing the durability of the mixture. At 80% sand, the durability of the concrete is so low as to make the concrete impracticable for almost all situa ⁇ tions except extremely low strength applications and mortars where no aggregates are included. Accordingly, the overall optimal mixture for concrete is defined by the mixture having the desired properties and the lowest unit price or the mixture having the desired properties and a 80% volume of sand.
  • the present system can be varied for designing mortars which contain only cement and one aggregate.
  • the volume of sand may be greater than 80%.
  • the available amount of fine aggregate in a mixture can be set by the user of the system based on the required durability of the concrete and the size of the aggregate.
  • the combination of Steps 1-3 reveals methods for designing a mixture of cement, water, and aggregate having a desired strength and slump.
  • the amount of water added to the mixture can be minimized to maximize strength.
  • the proportions of fine aggregate, coarse aggregate, and cement can be optimized to minimize the cost of the mixture.
  • mixtures having desired properties can be consistently and accurately produced independent of the variations in the feedstock.
  • Steps 1-3 can also be used to determine the mixture of highest durability.
  • the mixture with highest durability is defined as the mixture with the lowest possible total porosity. This is because, in general, as the porosity increases the durability of the mixture decreases. Studies have deter- mined that the porosity of a mixture decreases as the packing density increases. Thus, mixtures closest to the maximum packing density have the highest durability.
  • Step 4 Fly Ash Admixtures are those ingredients in concrete other than cement, fine aggregate, coarse aggregate, and water that are added to the mixture either before or during mixing to alter the properties or cost of the concrete.
  • the present invention provides models for representing the affects of adding the following admixtures to a concrete mixture: pozzolans (such as fly ash and silica fume) , water reducers, air-entraining agents, and fillers. By incorpo ⁇ rating these models into the previously disclosed optimization process, optimal concrete mixtures can be determined where such admixtures are included.
  • a pozzolan is a siliceous or aluminosiliceous material that in itself possesses little or no cementitious value but will, in finely divided form and in the presence of water, chemically react with the calcium, sodium, and potassium hydroxide released by the hydration of cement to form compound cementitious properties.
  • the two pozzolans that are most commonly used in the industry and that are incorporated into the present invention include fly ash and silica fume.
  • Fly ash is a mineral admixture that results from the combustion of pulverized coal in electric power generating plants.
  • fly ash comprises silicate glass containing silica, alumina, iron, and calcium. Minor constituents include magnesium, sulfur, sodium, potassium, and carbon.
  • ground particles such as cement, that have angular particles
  • fly ash is made of spherical parti ⁇ cles. The particles vary in size from l ⁇ m to more than lOO ⁇ m with a typical particle size under 20 ⁇ m.
  • fly ash can be a substitute for cement to increase slump and workability of the mixture without increasing the amount of water added.
  • fly ash can be substitu ⁇ ted for cement to decrease the amount of water added to the mixture while maintaining the same slump, thereby decreasing the water-cement ratio.
  • fly ash has some hydraulic cementitious properties that contribute to the strength of the resulting concrete.
  • the process includes first repeating Steps 1 and 2 so as to determine the optimal mixture (without an admixture) having desired strength and slump properties for a defined fine-to-coarse-aggregate ratio. Based on the composition of the resulting optimal mixture, a percent volume of cement is incrementally replaced with fly ash. As the percent volume of fly ash is increased, the unit price of each mixture is calculated and compared to the previous mixture to determine the least expensive mixture for the defined fine-to-coarse-aggregate ratio.
  • the fine-to-coarse-aggregate ratio is then varied by moving 1% to the left on the packing density chart.
  • the above process is then repeated to determine the least expensive mixture using fly ash with the new fine-to- coarse-aggregate ratio.
  • the unit price for the optimal mixtures at the different fine-to-coarse-aggregate ratios are then compared to determine the least expensive mixture.
  • the process continues to move to the left on the packing density chart until the overall optimal mixture having fly ash and the desired properties is obtained.
  • the specific process for cost optimization when the mixture includes fly ash comprises the following steps: 4 (a) . Determine the optimal mixture (with no admixtures) having the desired slump and strength at the initial fine-to-coarse-aggregate ratio -- this is the same process as defined in Steps 1 and 2.
  • the cement can be represented by a pseudo particle, as discussed in Step 1, that corresponds to the combination of the cement and fly ash.
  • a pseudo particle as discussed in Step 1
  • silica fume, fillers, and other pozzolans that will be discussed later.
  • W FA is a reduction, as a result of the fly ash, in the volume of water needed to produce a mixture with a desired slump and is determined by the equation:
  • VS X the volume of mixing water required for a 1.0 cm slump in a standard mixture as previously defined
  • %FA the percent volume of fly ash in the combination of fly ash and cement.
  • fly ash has some hydraulic properties, per equal volume of cement, fly ash contributes a lower strength to the mixture. Accordingly, the modified
  • Feret formula for determining the resulting 28-day strength of concrete using fly ash is :
  • K 2 a constant known as the strength reactivity that describes the strength development per volume of fly ash comparable to the same volume of cement. Typically, this value is between 0.3 and 0.6 and can be determined for the actual fly ash used,
  • Step 2 (d) the volume of fly ash in the mixture and is calculated according to the following equation: ⁇ - ⁇ • ( ⁇ 10 ⁇ ⁇ 24>
  • V C+FA the total volume of cement and fly ash and can be read off the packing density chart as the volume of cement
  • V c the volume of cement in the mixture and is calculated according to the following equation:
  • V C V C* FA V F.A
  • ⁇ D desired strength in MPa
  • K, K 2 , V A , W 2 and %FA are as previously defined in Step 4 (b) .
  • the volume of fly ash in the new mixture is calculated from the equation: FA 100 - %FA C ( 27 )
  • Steps 4(b) and 4(c) are then repeated until a mixture is obtained wherein the calculated strength equals the desired strength. 4 (d) .
  • Steps 4 (b) -4 (d) are continued to be repeated for increased values of fly ash until the least expensive mixture including fly ash is obtained or the percent volume of fly ash is greater than 30%. For mixtures with fly ash greater than 30%, there is insuffi- cient gelling of the cement to prevent segregation and bleeding of the concrete. Furthermore, as the hydration of fly ash has to be initiated by hydroxyl ions from the cement, higher dosages of fly ash cannot be recommended for proper strength development. 4(e) . As with Step 3, the process is now continued by changing the fine-to-coarse-aggregate ratio by decreasing the percent volume of coarse aggregate by 1%, thereby moving 1% to the left on the packing density chart . Using mixtures based on the new fine-to-coarse-aggregate ratio, repeat Steps 4 (a) -4 (d) so as to determine the least expensive mixture including fly ash and having the desired strength and slump properties.
  • Step 4(f) Calculate and compare the unit cost of the mixture in Step 4 (e) with the mixture in Step 4 (d) . If the mixture in Step 4(e) is less, Step 4(e) is again repeated by moving another 1% to the left on the packing density chart so as to vary the fine-to-coarse-aggregate ratio. The process continues by varying the fine-to-coarse- aggregate ratio so as to move left on the packing density chart until the overall least expensive mixture is obtained using fly ash or the percent fine aggregate reaches 80% as previously discussed.
  • pozzolans will behave similar to fly ash when combined with a concrete mixture.
  • such pozzolans include blast-furnace slag, pyrex, diatomaceous earth, opaline cherts, clays, shales, volcanic tuffs and pumicites.
  • Such pozzolans can be incorporated into the above optimization process by using the above equations with the appropriate water reduction and strength reactivity values.
  • not more than two pozzolans are added to a concrete mixture as there is seldom an economic benefit or an improvement in the material properties.
  • Silica fume also referred to as microsilica, is also a pozzolanic admixture but is distinguished from other pozzolans by its extremely large specific surface area and the way it affects concrete mixtures.
  • Silica fume is a result of the reduction of high-purity quartz with coal in an electrical arc furnace in the manufacturing of silicon or ferrosilicon alloy.
  • silica fume is silicon dioxide in amorphous form. Since it is formed as an air born particle, silica fume has a spherical shape like fly ash.
  • Silica fume particles are extremely fine having diameters less than l ⁇ m and an average diameter of 0.l ⁇ m.
  • the optimal mixture using silica fume can be ascertained in the same manner used in determining the proper amount of fly ash in Step 4; however, the formulas for the required amount of water and resulting strength are different. In contrast to fly ash, silica fume requires more water for a given slump, but silica imparts a greater strength to the cement mixture. With regard to the packing density chart, the volume of silica fume is also considered as part of the volume of cement in the mixture. If desired, a pseudo particle can be used to represent the combination of the cement and silica fume.
  • W SF is an increase, as a result of the silica fume, in the volume of water needed to produce a mixture with a desired slump and is determined by the equation:
  • %SF the percent volume of silica fume in the combination of silica fume and cement.
  • the value for W 2 can then be used to calculate the 28- day strength of the concrete.
  • the modified Feret formula for determining the resulting 28-day strength of concrete using silica fume is:
  • V SF the volume of silica fume in the mixture and is calculated according to the following equation:
  • V C+SF the total volume of cement and silica fume and can be read off the packing density chart as the volume of cement
  • V c the volume of cement in the mixture and is calculated according to the following equation:
  • Step 4 (c) an estimate for the volume of cement and silica fume needed ' to obtain the desired strength can be calculated.
  • the new volume of cement is calculated according to the following equation:
  • ⁇ D desired strength in MPa
  • K, K 3 , V A , W 2 and %SF are as previously defined.
  • Step 2 (e) The corresponding normalized volumes of fine aggregate and coarse aggregate can be calculated according to the equations in Step 2 (e) . Similar to fly ash, the volume of silica fume should not exceed 20% by volume of the combination of cement and silica fume. Concentrations in excess of 20% can limit the strength development of the mixture and result in drying shrinkage cracks due to the high specific surface area of the silica fume.
  • Water reducing admixtures are used to reduce the quantity of mixing water required to produce a concrete with a desired slump or workability.
  • Normal water reducers typically comprise 30% by weight an active component including lignosulfonates, hydroxylated carboxylic acids, and sulfonated naphthalene formaldehyde condensates, that can reduce the required amount of water needed to obtain a desired slump by approximately 15%.
  • High-range water reducers also referred to as superplasticizers, typically comprise 40% by weight an active component including sulfonated melamine formaldehyde condensates, sulfonated naphthalene formaldehyde condensates, and lignosulfonates, that can reduce the required amount of water ne" ed to obtain a desired slump by about 30%.
  • Water reducers also contain a retarding agent that retards the rate of strength development of the concrete. Unlike fly ash, however, water reducing admixtures have no cementitious properties and, thus, generally only affect the strength of the concrete by affecting the water-cement ratio.
  • Water reducers generally work by being adsorbed onto the surface of the cement particles . This creates a negative charge on the surfaces of the particles, causing them to repel each other. Because of this mechanism, water reducers can be thought of as dispersants. Normal water reducers and high-range water reducers have been found to lead to the same water reduction for equivalent concentra- tions of active ingredients.
  • the main difference between normal and high-range water reducers is that the high-range water reducers sold in commercial products simply have higher concentrations of the active dispersing ingredient and less of the retarding agent. Accordingly, the type of water reducing agent used in a mixture can be accounted for in the optimization process through a normalizing process discussed below.
  • the water reducers contain a retarding agent, no more than 1% of the solution of normal water reducers and 2% of the solution of high-range water reducers (by weight of cement) are generally added to a concrete mixture. Exceeding these concentrations of water reducers can inhibit the concrete from ever hardening. Higher concentrations of the high-range water reducers can be used since they contain less retarding agent.
  • the process for obtaining the optimal mixture is the same as that used for Step 4 to obtain the optimal mixture using fly ash. The only difference is that the formulas for determining the required amount of mixing water and the resulting strength are modified.
  • the process includes determining the optimal mixture for the first fine-to-coarse-aggregate ratio. Incremental amounts of water reducers are then added to the mixture. The unit cost of these mixtures are calculated and compared so as to determine the optimal mixture having water reducers at the initial fine-to-coarse-aggregate ratio. The fine-to-coarse-aggregate ratio is then varied and the process is repeated. By comparing the unit cost for the optimal mixtures at each fine-to-coarse-aggregate ratio, the overall optimal mixture using water reducers can be determined.
  • Step 4 Since the general process for obtaining an optimal mixture using a water reducing agent is the same as that discussed in Step 4, only the modified formulas to Step 4 will be discussed below in detail.
  • a water reducer is added in the amount of 0.1% by weight of cement in the optimal mixture.
  • the resulting strength is calculated using Feret ' s Equation. To calculate the resulting strength, however, the amount of water needed to obtain a desired slump in the mixture using the water reducer must be determined.
  • a high range water reducer typically has a concentration of active ingredient of about 40% by weight.
  • a 2% (by weight of cement) addition of such a water reducer to a cement mixture results in a 30% reduction in the amount of water required to obtain a desired slump.
  • Studies have found that the relationship between the addition of a water reducer and the reduction in the amount of water required is substantially linear.
  • all water reducers can be normalized accordingly. For example, the addition of 1% of a water reducer with only a 30% concentration of active ingredient is considered the same as adding 0.75% of the standard water reducer. This is because there is 25% less active ingredient in the new water reducer.
  • the percent volume of water needed to produce a mixture including a water reducer with a desired slump is determined by the following equation:
  • W WR is a reduction, as a result of the water reducer, in the volume of water needed to produce a mixture with a desired slump and is determined by the equation:
  • W x the volume of mixing water required for a 1.0 cm slump as previously defined
  • %WR the percent quantity of water reducer in the mixture by weight of the cement .
  • the value for W 2 can then be used to calculate the 28-day strength.
  • the same formulas used in Step 2 can be used for calculating 28-day strength and for estimating the volume of cement needed to obtain the desired strength.
  • the volume of water reducer in a mixture is so small that the quantity is not considered to change the volume of the mixture. If desired, however, the volume of water reducer can be accounted for.
  • the portion of water in the water reducer typically between about 60%-70% of the admixture, can be subtracted from the amount of water added to the mixture.
  • the remaining portion of the water reducer is a solid which can be substituted for a portion of the cement similar to how the fly ash and silica fume were substituted for the cement in Steps 4 and 5, respectively.
  • the amount of water required for the desired slump is decreased by using a water reducing agent, the water-cement ratio in the mixture is decreased, thereby, increasing the strength of the resulting mixture. Accordingly, the amount of cement can be reduced until a mixture is defined possessing the desired strength and slump and having the initial 0.1% water reducing agent. A cost comparison is then performed and if the mixture with the water reducer is cheaper, an additional 0.1% water reducer is added to the mixture . The above process is then again repeated according to the format in Step 4 until the optimal mixture including a water reducer is determined. As previously discussed, however, water reducers are generally only added up to approximately 2% of the weight of cement. Quantities above that amount increase the setting time of the concrete to an impractical duration.
  • water-reducing admixtures will not be added to low strength concrete. Since only a minimal amount of cement is required for such mixtures, the addition of expensive water reducers is cost prohibitive. However, in high strength concrete, the addition of a water reducer can significantly reduce the amount of cement re- quired, thus, making the water reducing agent economical to use.
  • Fillers are another admixture that can be included in the optimization process.
  • a concrete mixture generally requires at least 10% cement by volume of the cement, fine aggregate, and coarse aggregate to produce a cohesive mixture that prevents segregation and bleeding of concrete.
  • Some low strength concretes however, can obtain the desired strength with less than 10% cement.
  • inexpensive fillers having particles substantially the same size as cement particles can be used to make up the difference between the required amount of cement necessary to obtain the desired strength and the 10% cement necessary to obtain a cohesive mixture.
  • Fillers generally do not possess cementitious proper ⁇ ties and, thus, do not directly contribute to the strength of the resulting concrete. Similar to fly ash, however, fillers do decrease the amount of mixing water required to obtain a desired slump as compared to cement and, accordingly, can indirectly affect the slump and strength of the resulting concrete.
  • fillers can include calcium carbonate, dolo ⁇ mite, granite, basalt, and ore that are crushed to have a particle size similar to fly ash -- diameters less than 100 ⁇ m. The reduction in the amount of water need to obtain a desired slump is a result of the approximately spherical shape of the fillers and lack of hydraulic activity.
  • Fillers are typically incorporated in a concrete mixture independent of pozzolans or other admixtures. Since fillers are only used in low strength mixtures, the addition of pozzolans, which generally have half the strength, but more than twice the cost of cement, only serves to increase the cost of the mixture.
  • the minimum percent volume of cement needed in a mixture to prevent segregation and bleeding is about 10%.
  • the percent volume of cement can continue to be decreased by replacing the cement with a filler.
  • the packing density chart even though fillers are replacing cement, the percent volume of cement remains constant at 10% since fillers have the same packing characteristics as cement.
  • the combination of fillers and cement can be represented as a pseudo particle.
  • the volume of water needed to produce a mixture including a filler with a desired slump is determined by the following equation:
  • W F is a reduction, as a result of the filler, in the volume of water needed to produce a mixture with a desired slump and is determined by the equation:
  • %FIL the percent volume of filler in the combination of filler and cement.
  • the value for W 2 can then be used to calculate the 28-day strength.
  • the same formulas used in Step 2 can be used for calculating the 28-day strength and for estimating the volume of cement needed to obtain the desired strength.
  • Step 8 Combined Design Optimization System
  • box 34 requests a list of all types of cement, fine aggregate, and coarse aggregate that are to be incorporated into the mixture.
  • the types of components are classified by their average diameter size, d' , and packing density, ⁇ , as shown in box 36.
  • d' average diameter size
  • packing density
  • the system then asks in box 40 whether silica fume is to be a possible component in the mixture. If no silica fume is to be used, the maximum amount of silica fume is set equal to zero in box 42. If silica fume can be used, the maximum amount is defined in box 44. As discussed in Step 5, the volume of silica fume should typically not exceed 20% of the volume of cementitious material. With regard to the presently described system, the term "cementitious materials" includes cement, fly ash, and silica fume. Boxes 46-50 request the same information for water reducers while boxes 52-56 request the information on the use of fly ash.
  • the initial parameters are defined by setting the heretofore best mixture cost, X BEST ' equal to infinite and setting the amount of water reducer, fly ash, and silica fume equal to zero as shown respectively in boxes 58-62.
  • the system is now ready to determine the composition and cost of the initial mixture having the desired strength and slump properties. This process is performed in tree 64 which is depicted in Figure 9.
  • Box 66 begins the optimization process by calculating the maximum packing density for the given cement, fine aggregate, and coarse aggregate.
  • the maximum packing density is determined according to the process described in Step 1.
  • the cohesion safety factor, shown in box 68, is then applied to the composition of the mixture at the maximum packing density so as to define an initial mixture, as shown in box 70, that will not segregate or bleed.
  • Box 69 initially sets the optimal cost mixture equal to infinity for later comparison with the actual cost.
  • box 72 the volume of water needed for the mixture to obtain the desired slump is calculated. Based on the required amount of water, the resulting strength of the mixture is determined in box 74. Box 76 then compares the calculated strength with the desired strength. Assuming the calculated strength does not equal the desired strength, an estimated volume of cement necessary to obtain the desired strength is calculated in box 78. Furthermore, box 78 renormalizes the volume of fine aggregate and coarse aggre ⁇ gate so that the volume of cement, fine aggregate, and coarse aggregate in the new mixture sum to 1.0 while the fine-to-coarse-aggregate ratio remains constant. The above calculations are all performed according to the equations in Step 2.
  • the system then returns to box 72 through loop 79 where the process is repeated for the new mixture by calculating the required water and resulting strength and then comparing the calculated strength to the desired strength. Loop 79 continues until the calculated strength equals the desired strength, at which point the cost of the defined mixture is calculated in box 80. Box 82 then compares the cost of the mixture from box 80 with the cost of the optimal mixture. Since the cost of the optimal mixture is initially set to infinity, the first mixture having the desired properties is defined as the optimal mixture and the values for volume of cement, fine aggregate, and coarse aggregate, along with the cost of the mixture are so defined in box 84.
  • the system compares in box 86 the volume of fine aggregate in the mixture with the maximum volume of fine aggregate allowed. As discussed in Step 2, this is typically about 80% by volume of the solids. If the volume of fine aggregate in the mixture is less than the allowable fine aggregate, the system moves to box 88 where a new fine-to-coarse-aggregate ratio is defined by increasing the volume of fine aggregate by 1% and decreasing the volume of coarse aggregate respectively; the volume of cement is held constant. The system then returns to box 70 through loop 89 where the process is repeated by determining what composition of cement, fine aggregate, and coarse aggregate, at the newly defined fine-to-coarse-aggregate ratio, will result in a mixture that has a calculated strength equal to the desired strength.
  • the mixture having the desired properties at the new fine-to-coarse-aggregate ratio is determined, its cost is calculated in box 80 and compared to the previously defined optimal mixture. If the cost of the new mixture is less, the new mixture becomes the optimal mixture and loop 89 continues by defining a new fine-to-coarse- aggregate ratio in box 88. Loop 89 continues until it is exited through either box 82 or 86. Loop 89 exits through box 86 when the volume of fine aggregate of the newly defined optimal mixture is equal to or greater than the defined maximum volume of fine aggregate. Loop 89 can also exit through box 82 if the cost of the new mixture is found to be more expensive than the cost of the defined optimal mixture.
  • the optimal mixture corresponds to the overall best composition of cement, fine aggregate, and coarse aggregate that has the desired strength and slump with a minimal cost.
  • Box 90 compares the cost of the optimal mixture defined by box 84 to the best cost mixture. Since the best cost is initially set to infinity in box 58, the best cost in box 92 is initially set to the optimal mixture defined in box 84 at the time loop 89 is exited. Box 92 stores the composition and cost of the best mixture.
  • the system enters a series of embedded "do loops" which incrementally increase the volume of silica fume, fly ash, and water reducer.
  • the cost for each of the optimal mixtures are compared, and the best mixture is stored in box 92.
  • Box 94 asks whether the amount of silica fume in the mixture is less than the defined allowable amount of silica fume. If yes, the volume of silica fume in the cementitious material is increased by 1% as shown in box 96. The system then returns via loop 97 to tree 64.
  • tree 64 now determines the composition and cost of mixtures having silica fume and desired properties for varying fine-to- coarse-aggregate ratios; the ratio of silica fume to cementitious materials being held constant for each mixture.
  • Loop 89 continues to vary the fine-to-coarse-aggregate ratio until a new mixture is more expensive than a previous mixture as compared in box 82 or the maximum volume of fine aggregate is reached.
  • the system returns to box 90 and the cost of the optimal mixture in box 84 is compared to the cost of the previous best mixture. If the cost of the optimal mixture is less expensive, the composition of optimal mixture becomes the best mixture.
  • the system then checks to see if the maximum amount of silica fume has been reached, if not, an additional 1% of the volume of the cementitious material is substituted for silica fume. Loop 98 is then repeated to find the new optimal mixture at the new set silica fume to cementitious material ratio. Loop 98 is continually repeated until the amount of silica fume in the mixture reaches the maximum amount of silica f me.
  • the system asks in box 100 whether the maximum amount of fly ash in the mixture has been reached. If not, 1% of the volume of cementitious material is replaced by fly ash in box 102. Loop 104 then returns the system to box 62 where the volume of silica fume is reset to zero and tree 64 is entered again.
  • Tree 64 now uses the formulas as disclosed in Step 4 to determine the optimal mixture having cement, 1% fly ash (based on the volume of cementitious material) , fine aggregate and coarse aggregate. Once this mixture is obtained, its cost is compared to the cost of the best mixture in box 90. The silica fume is then incrementally added to mixture as loop 98 is repeated. As loop 98 incrementally increases the value of silica fume, the system determines the optimal mixture for compositions having cement, 1% fly ash, silica fume, fine aggregate, and course aggregate. Once the allowable amount of silica fume equals the maximum amount of silica fume, loop 98 is exited and the percent volume of fly ash is again increased by 1%. The volume of silica fume is then again set to zero and incrementally increased as loop 98 is repeated with a 2% volume of fly ash. This cycle continues until the volume of fly ash in the mixture equal the maximum amount of fly ash.
  • the system then asks in box 106 if the volume of water reducer is greater than the allowable amount of water reducer. If not, a water reducer is added to the mixture in the amount of 0.1% by weight of the cementitious material. Loop 110 then returns the system back to box' 60. The system then repeats loops 98 and 104 for each incremental increase of water reducer.
  • the cost is compared to the best mix cost stored in box 92. According- ly, when the amount of water reducer is equal to the maximum amount of water reducer and the system ends by exiting to box 112, the best mixture stored in box 92 corresponds to the least expensive mixture having the desired properties of slump and strength based on all possible combinations of cement, fly ash, silica fume, water reducers, fine aggregate, and coarse aggregate.
  • the calculations for the amount of water required and the resulting strength of a mixture can be calculated according to the formulas in Step 4 and 5 respectively.
  • the cement, fly ash, and silica fume are combined in a single mixture, the following equations are to be used.
  • the amount of water required to give a mixture including silica fume and fly ash a desired slump is determined from the equation:
  • W SF and W FA are as defined in Steps 4 and 5.
  • ⁇ v sF ⁇ : % o SF r ' ( -V V ⁇ T / '1 ⁇ 0 U 0- J )I (41) V F . - %FA - (V /100) ( 42 )
  • V ⁇ the total volume of cement, silica fume, and fly ash in the mixture.
  • the other variables are as previously defined in Step 4 and 5. Should the desired strength not equal the calculated strength, the estimated values for the new volumes of cement, fly ash, and silica fume can be calculated from the following equations, respectively:
  • V SF(N) 100 - % £ S iUF (46)
  • the required amount of water for a desired slump in a mixture containing cement, fly ash, silica fume, water reducer, fine aggregate, and coarse aggregate is determined by the following equation:
  • Air-entraining agents are not modeled into the optimization process and thus must be corrected after the fact.
  • Air-entraining agents are admixtures that stabilize bubbles formed during the mixing process. This is accomplished by lowering the surface tension of the water.
  • the air-entraining agent forms a water repelling film that is sufficiently strong to contain and stabilize air bubbles.
  • air bubbles formed through the use of an air-entraining agent are extremely small and have a diameter size ranging from about 10 to about 1000 ⁇ m.
  • the primary benefits to increasing the percent volume of air voids in a concrete mixture are the improved resistance to freezing and thawing of hardened concrete in moist condition and the increased workability of the concrete mixture.
  • the air voids relieve these pressures by acting as empty chambers in which the freezing water can expand without exerting undue internal pressures on the concrete structure.
  • Air-entraining agents slightly increase the slump and workability of a concrete mixture by providing air bubbles over which the particles of the mixture can travel, thereby decreasing the friction force between the particles.
  • Typical air entraining agents include salts of wood resins (vinsol resin) , some synthetic detergents, salts of sulfonated lignin, salts of petroleum acids, salts of proteinaceous material, fatty and resinous acids and their salts, alkylbenzene sulfonates, and salts of sulfonated hydrocarbons.
  • air-entraining agents are added in amounts of about 0.02% to about 0.2% by weight of the cement (depending on the type and amount of solids in the air- entraining agents) to introduce an air content from about 4% to about 10% by volume of the concrete.
  • concentration of an air-entraining agent depends on the co esiveness of the concrete mixture.
  • the dosage added to the mixtures in the optimization process is typically the recommended dosage from the sales company.
  • the air- entraining agent Sika Aer ® from the Sika company should be dosaged in a concentration of 0.04% of the cement weight to give an air content of about 5% by volume of the concrete.
  • the actual air content in the mixture can be determined. If the air content for a given slump after completion of the optimization process is too low or too high compared to the assumed air content used in Step 2 (c) , the optimization process can be recalculated using the corrected value for the content of air or the mixture can be reformed with the appropriate amount of air-entraining agent.
  • the air content can also modeled according to the discussion in Step 10. As with water reducers, the percent volume of an air entraining agent in a mixture is typically so small that the agent itself is not taken into account as affecting the volume of the mixture. However, the resulting amount of air incorporated into the mixture is taken into consideration in determining the strength of the mixture.
  • a linear regression analysis can be used to improve the accuracy of the system results. In general, this is accomplished by plotting the theoretically determined amount of mixing water required to obtain a desired slump versus the actual amount mixing water required to obtain a desired slump. The relationship between the plotted values is then defined and incorporated into Popovic ' s formula so as to increase the accuracy of the theoretical amount of water required to obtain a desired slump.
  • the above process includes the following steps : 10 (a) .
  • Step 10(c) Using Popovic's formula, solve for the amount of water, W 2 , needed to give the defined mixture the actual slump determined in Step 10(b) .
  • Steps 10(b) and 10(c) now give the actual and theoretical amounts of water, respec ⁇ tively, required to give a specific mixture a specific slump.
  • Step 10(d) Repeat Steps 10 (a) -10(d) for different desired slumps. The steps should be repeated at least three times with the accuracy of the final results improving the more the steps are repeated. This provides two sets of values corresponding to the actual and theoretical amounts of water required to obtain a defined slump. 10(e) . Plot the values of Step 10(d) with the actual amount of water required for a specific slump on the y-axis and the theoretical amount of water required for a specific slump on the x-axis. Studies have shown that such a plot will reveal a linear relationship. 10(f) . Define the linear relationship of Step 10(e) in the following form:
  • W 2c actual amount of water for a defined slump (in use, the value represents the corrected theoretical amount of water for a defined slump) ,
  • AIR ACT the volume of air in a mixture based on the corresponding slump
  • SLUMP the slump for a given mixture
  • m slope of the plot of actual slump versus correspond air content
  • b the y intercept of the slope
  • Step 10(h) The formula of Step 10(f) is then incorporated into the design optimization process such that after the theoretical amount of mixing water required for a desired slump is solved for from Popovic' s formula, the resulting value for W 2 is inputed into equation (48) in Step 10(f) .
  • W 2c is then solved for providing an improved or corrected value for the amount of water required to obtain a desired slump.
  • the desired slump is then incorporated into equation (49) to obtain the volume of air in the mixture.
  • the resulting volume of air and corrected water volume are then used in the Feret equation to solve for the strength of the mixture.
  • the optimization process then continues as previously discussed. In this way the slump can be estimated within plus or minus 2 cm.
  • Step 11 Durability
  • Durability is the ability of a concrete structure to maintain its integrity over an extended period of time and is measured in this patent in terms of porosity. Mixtures with a high porosity typically have an excessively high concentration of water or fine aggregate and as such have low durability. Total porosity of a mixture can be determined by the following equation, where it is assumed 80% of the hydration of the cement has already occurred.
  • W w weight of water per cubic meter of concrete
  • W c weight of cement per cubic meter of concrete
  • %Air percent volume of air in mixture based on volume of solids in mixture.
  • the above equation can thus be used with the slump and strength to insure that a mixture has desired properties. That is, once a mixture has been found to have sufficient strength and slump, the total porosity can be calculated to determine if it satisfies the desired porosity. If the desired porosity is insufficient, the percent volume of cement can be increased, thereby decreasing the porosity of the structure and insuring that it has sufficient durability.
  • Step 12 Yield Once the proportions of the best overall mixture are determined, it is desirable to be able to calculate what volumes of the components will produce a desired yield or volume of the mixture.
  • the present manufacturing processes generally overestimate the yield of a mixture.
  • the volume of a proposed mixture is typically calculated by dividing the weight of each component by its respective density to obtain the volume of each component .
  • the volume of each of the components are then added together to obtain the sum volume of the resulting mixture.
  • the present invention discloses a method for determining the yield of a mixture in which the volume of air in the mixture is taken into consideration.
  • the process entails dividing the volume of each component (as determined by the previously discussed optimization process) by the total volume of the mixture and then multiplying the corresponding fractions by the desired volume of the mixture. These calculations determine the actual volume of each component that should be added to produce a mixture of a desired volume.
  • the volume of the components can be multiplied by their respective specific gravity to determine what weight of each component should be added to a mixture to obtain a desired yield of a mixture.
  • the volume of cement needed to produce 100 cubic meters of a defined mixture can be determined by the following equation:
  • V c the volume of cement in the mixture determined in Step 10 of the optimization process and is represented as a fraction of the solids in the mixture.
  • the solids i.e., cement, fine aggregate, coarse aggregate and, when relevant, fly ash and silica fume) summing to 1.0.
  • V ⁇ the total volume of the optimized mixture defined in Step 8.
  • V ⁇ is obtained by adding the volume of water, w, in the mixture to the volume of solids (which sum to 1.0) and dividing the sum by the volume of air in the mixture.
  • the total volume is represented by the following equation:
  • the percent air, %Air, in the mixture can be empirically determined by a trial mix. Using the above equation for each of the components in the mixture, the volume of each of the components needed to produce a mixture with a desired yield can be accurately determined.
  • Example 1 Sand and pea gravel were mixed with Type 1 portland cement in the design of a pea gravel foundation concrete mix. The aggregates were characterized to determine the d' and packing density of each component :
  • FIG. 10 shows the correlation between the corrected theoretical packing density and the experimental packing density of the sand and the pea gravel. As the best fit line follows the line of direct proportionality, the behavior indicates a perfect model description.
  • Figure 11 shows the correlation between the corrected theoretical ternary packing density and the experimental ternary packing density of the cement, sand and pea gravel. It is seen from the Figure 11 that an accurate model is obtained for estimating the packing properties.
  • the advantage over conventional design methods is that it basically requires only two mix designs to perfect the model and predict a concrete with the correct strength, air content and slump at the lowest possible materials cost.
  • Example 2 Sand and pea gravel were mixed with Type 1 portland cement in the design of a pea gravel foundation concrete mix.
  • the previously described were used to estimate the design of a pea gravel mix containing a maximum of 50 volume % sand of the total volume of cement, sand, and pea gravel and a strength of 25 MPa.
  • a slump of 5 cm and an air content of 2.5 volume % was anticipated.
  • the following first optimized mix design was predicted:
  • the result is a concrete with the correct strength, air content, and slump at the lowest materials cost.
  • Example 3 Sand and pea gravel were mixed with Type 1 portland cement and fly ash in the design of a pea gravel foundation concrete mix.
  • the previously described models for fly ash were used to estimate the design of a pea gravel mix containing a maximum of 60 volume % sand of the total volume of cement, sand, and pea gravel; a maximum of 30% fly ash of the weight of cement; and a strength of 30 MPa.
  • a slump of 5 cm and an air content of 2.0 volume % was anticipated: The following first optimized mix design was predicted:
  • This equation is now used in predicting the actual air content for use in determining the strength of the mixture.
  • the derived models can now be used for a precise estimation of the slump of concrete.
  • Example 4 Sand and pea gravel were mixed with Type 1 portland cement and an air entraining agent in the design of a pea gravel foundation concrete mix.
  • the previously described models in Steps 9 and 10 were used to estimate the design of a pea gravel mix containing a maximum of 60 volume % sand of the total volume of cement, sand and pea gravel, 0.04% air entraining agent of the weight of cement, and a strength of 25 MPa.
  • a slump of 20 cm and an air content of 3.0 volume % was anticipated.
  • the following first optimized mix design was predicted:
  • a low strength concrete was to be designed with the use of a calcium carbonate filler.
  • the concrete was designed for 15 MPa and 60% maximum sand of the total volume of cement, filler, sand and pea gravel. To insure a good cohesion, a minimum of 10% by volume of the cement and filler of the total volume of cement, filler, sand and pea gravel was to be used. After setting up the model with the first two mixes as described in Example 1 and Example 2, the following mix was designed for a slump of 3.5 cm:
  • filler With the use of filler, only the necessary amount of cement for the desired strength is used; the cohesiveness is obtained with the addition of the filler. If filler was not used, additional cement would be used to insure cohesiveness and would give an optimal concrete with a strength of 20.7 MPa. Comparing the two mixes, the materials cost reduction with the use of filler is $3.60/m 3 .
  • Example 6 Sand and pea gravel were mixed with Type 1 portland cement and superplasticizer in the design of a pea gravel foundation concrete mix.
  • the previously described models in Step 8 for water reducers were used to estimate the design of a pea gravel mix containing a maximum of 50 volume % sand of the total volume of cement, sand and pea gravel, a maximum of 2% WRDA-19 of the weight of cement, and a strength of 35 MPa.
  • a slump of 2 cm and an air content of 9.0 volume % was anticipated.
  • the following first optimized mix design was predicted: cement 383 . 0 kg/m 3
  • Example 7 A contractor requested concrete to be transported to a building site with a slump loss of no more than 5.0 cm in a 1/2 hour period.
  • the concrete was to be of a 35 MPa strength with a slump on site of 10.0 cm.
  • the concrete was designed according to Example 6, however instead of using a maximum superplasticizer of 2% WRDA-19, a combination of normal water reducer and superplasticizer was used to reduce the slump loss. According to the following mix design, the maximum recommended dosage of 1.0% of normal plasticizer (WRDA-79) was used together with 1.0% of superplasticizer (WRDA-19) which was added to achieve the total maximum design concentration of 2.0%. Cement 414 kg/m3
  • the example demonstrates the predictability of the slump behavior with the use of both normal water reducers and high range water reducers.
  • Example 8 A concrete mixture was designed according to the ACI 211.1.89 standard, "Recommended Practice for Selecting Proportions for Normal, Heavyweight and Mass Concrete” for a compressive strength of 25 MPa and a slump of 5 cm. The cost of the materials used was :
  • the coarse aggregate had a maximum size of 10 mm and the sand a fineness modules of 2.34 -2.4.
  • the advantage of using the described method over the ACI standard is that the actual slump and strength is accomplished while simultaneously incurring a cost savings of 2.79 $/m 3 .
  • Example 9 A concrete mixture was designed according to the ACI 211.1.89 standard, "Recommended Practice for Selecting Proportions for Normal, Heavyweight and Mass Concrete” for a compressive strength of 25 MPa and a slump of 10 cm. The cost of materials used was:
  • the coarse aggregate has a maximum size of 10 mm and the sand a fineness modules of 2.34 2.4.
  • the following mix was designed according to ACI recommendations:
  • the advantage of using the described method over the ACI standard is that the actual slump and strength is accomplished while simultaneously incurring a cost savings of 4.24 $/m 3 .
  • the coarse aggregate has a maximum size of 10 mm and the sand a fineness modules of 2.34 -2.4.
  • the following mix was designed:
  • the advantage of using the described method over the ACI standard is that the actual slump and strength is accomplished while simultaneously incurring a cost savings of 6.30 $/m 3 .
  • EXAMPLE 11 A ready mix concrete plant was producing a pumpable pea gravel foundation mix with a slump of 10 cm and a com ⁇ pressive strength of 13.8 MPa with the following mix design:
  • the strength was slightly over designed as a safety precaution.
  • a ready mix concrete plant was producing a pumpable pea gravel foundation mix with a slump of 10 cm and a compressive strength of 17.2 MPa with the following mix design:
  • the concrete was designed according to the above system for a slump of 10 cm and a strength of 20.0 MPa (an increase of 2.8 MPa) .
  • the strength was slightly over designed as a safety precaution.
  • a ready mix concrete plant was producing a pumpable pea gravel foundation mix with a slump of 10 cm and a compressive strength of 20.7 MPa with the following mix design:
  • the concrete was redesigned according to the above system for a slump of 10 cm and a strength of 23.5 MPa. The strength was slightly over designed as a safety precaution. Cement 307 kg/m 3
  • EXAMPLE 14 A ready mix concrete plant was producing a 1" rock mix with a slump of 10 cm and a compressive strength of 13.8 MPa.
  • the typical mix was:
  • EXAMPLE 15 A ready mix concrete plant was producing a 1" rock mix with a slump of 10 cm and a compressive strength of 17.2 MPa.
  • the typical mix was:
  • EXAMPLE 16 A ready mix concrete plant was producing a 1" rock mix with a slump of 10 cm and a compressive strength of 20.7 MPa.
  • the typical mix was:
  • EXAMPLE 17 A ready mix concrete plant was producing a 1" rock mix with a slump of 10 cm and a compressive strength of 27.6 MPa.
  • the typical mix was:
  • EXAMPLE 18 In conventional concrete batching, the weighing of the individual components has become more and more precise. Using state of the art equipment, the amount of water today can be weighed with a precision of 1 liter of water per m 3 . However, when recording the ' slump, large variations are observed from batch to batch of concrete even though all components are weighed very precisely. If too low a slump is recorded then more water is typically added, resulting in too high a water-to-cement ratio and hence, an uncontrolled decrease in the compressive strength. If however, too high a slump is recorded then excessive bleeding and/or segregation may lead to detrimental internal defects and an overall low quality of concrete.
  • Figure 27 shows the packing density for a pea gravel tested once per day. The figure shows lines indicating the average, the minimum and the maximum packing densities.
  • Figure 28 shows the d' of the same samples of pea gravel as shown in Figure 27. Again the average, minimum and maximum d' is shown by lines in the figure. Based on Figure 18 and Figure 19, it can be concluded that the observed variations in the pea gravel are large and account for the observed variations in slump in the production. The results indicate the need for a continuous control of the materials variation to improve the overall concrete quality.
  • EXAMPLE 21 The materials variations shown in Examples 18, 19, and 20 have been found to have a dramatic effect on the slump of the actual concrete and therefore also on the necessary amount of water to be added for a given slump and the necessary cement content for a given strength.
  • EXAMPLE 22 The materials variations shown in Examples 18, 19 - and 20 have been found to have a dramatic effect on the slump of the actual concrete and therefore also on the necessary amount of water to be added for a given slump and hence also on the necessary cement content for a given strength. In designing the pea gravel mix discussed in
  • Example 12 it was found that if the sand and pea gravel are combined according to the variation shown in Figures 27-32, that is combining the highest and lowest packing of the two components, then the designed concrete with a 10 cm slump and a strength of 17.2 MPa would cost:
  • EXAMPLE 25 The materials variations shown in Examples 18, 19 and 20 have been found to have a dramatic effect on the slump of the actual concrete and therefore also on the necessary amount of water to be added for a given slump and hence also on the necessary cement content for a given strength.
  • EXAMPLE 26 The materials variations shown in Examples 18, 19 and 20 have been found to have a dramatic effect on the slump of the actual concrete and therefore also on the necessary amount of water to be added for a given slump and hence also on the necessary cement content for a given strength.
  • the 1" rock mix discussed in Example 16 it was found that if the sand and rock are combined according to the variation shown in Figures 27-32, that is combining the highest and lowest packing of the two components, then the designed concrete with a 10 cm slump and a strength of 20.7 MPa would cost:
  • EXAMPLE 27 The materials variations shown in Examples 18, 19 and 20 have been found to have a dramatic effect on the slump of the actual concrete and therefore also on the necessary amount of water to be added for a given slump and hence also on the necessary cement content for a given strength.
  • EXAMPLE 28 The results disclosed in Examples 21-27 have demon ⁇ strated that an on-line monitoring of the variations of d' and the packing density of concrete materials have shown:
  • EXAMPLE 31 The concretes designed in Examples 11-17 showed good cohesiveness and negligible bleeding and segregation when compared to the normal mix designs at the ready mix plant .
  • EXAMPLE 32 Three types of coarse aggregates: granite in the range of 2-8 mm, granite in the range of 8-16 mm, and granite in the range of 16-32 mm, were to be used for a concrete bridge construction with high durability and an expected life span of 100 years. For this reason the porosity had to be minimized and the concrete had to be workable at the minimum water content.
  • the aggregates were therefore packing optimized to increase the workability of the concrete.
  • the aggregates had the following packing densities and average particle sizes : d' ⁇ '
  • the present invention provides novel processes and manufac ⁇ turing techniques for consistently and predictably producing uniform cementitious compositions and products which can be assured to meet predetermined quality characteristics and to meet predetermined performance criteria.
  • the present invention also provides consistent and predictable novel cementitious composition and products which would meet the predetermined design and performance criteria while minimizing the need to overdesign the cementitious materials and thereby minimizing the cost of manufacture.
  • the present invention also provides methods to produce consistently and predictably such uniform cementitious compositions and products even though feedstocks (e . g. , cement, sand, gravel, aggregates, water, and admixtures) having variable qualities and attributes are utilized.
  • feedstocks e . g. , cement, sand, gravel, aggregates, water, and admixtures
  • the present invention also provides novel compositions and processes for producing cementitious compositions and products being assured that the resultant product was such that the truck driver would not need to modify the mix specifications .
  • the present invention provides methods to produce cementitious compositions and products that have sufficient durability for their intended use.
  • the present invention provides novel processes for designing concrete such that the cementitious compositions meet the required strength, slump, and durability characteristics.
  • the present invention also provides novel compositions and processes for designing concrete such that trial and error approximation is eliminated.
  • the present invention provides novel compositions and processes for designing concrete such that the mix design for a certain concrete having a variety of components and admixtures will be known to be optimal and at the same time the most cost effective.
  • the present invention provides novel processes for modifying in "real time” the manufacturing processes of cementitious compositions and products in response to changes on site of the feedstock materials.

Abstract

Procédé de production d'un mélange de ciment à conception optimisée comprenant les étapes suivantes: calcul de la densité de tassement maximum du ciment, granulat fin et granulat grossier (66); établissement d'un mélange (69) à coût optimum; calcul du volume d'eau pour un affaissement souhaité (72); détermination de la résistance (74) du mélange de ciment; comparaison de la résistance calculée et de la résistance souhaitée (76); calcul du coût (80) du mélange; comparaison avec le coût (82) optimum de mélange; comparaison du volume de granulat fin au volume maximum de granulat fin autorisé.
EP94927185A 1993-08-18 1994-08-18 Compositions optimisees et procedes de conception microstructurelle de melanges de ciment Ceased EP0714383A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US109100 1987-10-16
US10910093A 1993-08-18 1993-08-18
PCT/US1994/009328 WO1995005350A1 (fr) 1993-08-18 1994-08-18 Compositions optimisees et procedes de conception microstructurelle de melanges de ciment

Publications (2)

Publication Number Publication Date
EP0714383A1 EP0714383A1 (fr) 1996-06-05
EP0714383A4 true EP0714383A4 (fr) 1998-04-01

Family

ID=22325767

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94927185A Ceased EP0714383A4 (fr) 1993-08-18 1994-08-18 Compositions optimisees et procedes de conception microstructurelle de melanges de ciment

Country Status (15)

Country Link
EP (1) EP0714383A4 (fr)
JP (1) JPH08511486A (fr)
CN (1) CN1100395A (fr)
AU (1) AU679784B2 (fr)
BR (1) BR9407168A (fr)
CA (1) CA2168643A1 (fr)
CO (1) CO4520143A1 (fr)
EG (1) EG20631A (fr)
IL (1) IL110605A (fr)
NZ (1) NZ273435A (fr)
PE (1) PE33195A1 (fr)
RU (1) RU2135427C1 (fr)
WO (1) WO1995005350A1 (fr)
ZA (1) ZA945497B (fr)
ZW (1) ZW10394A1 (fr)

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994012328A1 (fr) * 1992-11-25 1994-06-09 E. Khashoggi Industries Compositions a charge elevee de substances inorganiques
DE19857728C2 (de) * 1998-12-12 2001-11-29 Maxit Holding Gmbh Fließestrich-, Putz-, Beton- oder Mörteltrockenmischung mit wenigstens zwei pulverförmigen Mehlkornanteilen und Verfahren zu deren Herstellung
US6379031B1 (en) * 2000-01-20 2002-04-30 Aggregate Research Industries, Llc Method for manufacturing concrete
ATE340779T1 (de) * 2002-02-16 2006-10-15 Schlumberger Technology Bv Zementzusammensetzungen für hochtemperaturanwendungen
CN1321787C (zh) * 2004-05-14 2007-06-20 上海交通大学 混凝土搅拌车搅拌筒内搅和料流固两相流的建模方法
EP2026224A2 (fr) * 2005-06-17 2009-02-18 iCrete, LLC Procédés et systèmes pour la fabrication de béton optimisé
RU2446123C1 (ru) * 2010-11-30 2012-03-27 Юлия Алексеевна Щепочкина Бетонная смесь
RU2448214C1 (ru) * 2011-02-07 2012-04-20 Василий Петрович Ягин Узел сопряжения грунтовой плотины с бетонной водосливной плотиной
RU2474493C1 (ru) * 2011-07-19 2013-02-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Самарский государственный архитектурно-строительный университет" (СГАСУ) Способ производства ячеисто-бетонной смеси
RU2513372C1 (ru) * 2013-02-19 2014-04-20 Юлия Алексеевна Щепочкина Сырьевая смесь для изготовления материала, имитирующего природный камень
RU2540426C1 (ru) * 2013-08-13 2015-02-10 Федеральное государственное автономное образовательное учреждение высшего профессионального образования "Северный (Арктический) федеральный университет имени М.В. Ломоносова" (САФУ) Способ определения состава сухой строительной смеси для бетона
RU2578700C1 (ru) * 2014-11-17 2016-03-27 Общество с ограниченной ответственностью "Химком" Способ определения состава бетонной смеси
RU2633623C1 (ru) * 2016-05-31 2017-10-16 Федеральное государственное бюджетное образовательное учреждение высшего образования "Тульский государственный университет" (ТулГУ) Бетонная смесь
WO2018156122A1 (fr) 2017-02-22 2018-08-30 Halliburton Energy Services, Inc. Régulation de la chaleur d'hydratation par caractérisation de constituants cimentaires
WO2019053495A1 (fr) * 2017-09-13 2019-03-21 Saroj Vanijya Private Limited Procédé de production de matières premières destinées à être utilisées dans la production d'un matériau de construction à mélange sec
CA3129740A1 (fr) * 2019-02-11 2020-08-20 Construction Research & Technology Gmbh Systemes et procedes permettant de formuler ou d'evaluer un adjuvant de construction
CN114790093B (zh) * 2021-01-26 2022-12-02 中国石油天然气股份有限公司 一种水泥浆的确定方法
CN113813839A (zh) * 2021-02-24 2021-12-21 晋江华宝石业有限公司 一种方料快速级配方法及其级配装置
US11703499B2 (en) * 2021-09-24 2023-07-18 X Development Llc Method to produce evolving concrete mixture heuristic
CN114357723A (zh) * 2021-12-10 2022-04-15 江苏中利集团股份有限公司 多组分聚合物生产中辅料对材料结构的评估方法和系统

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3754954A (en) * 1971-08-10 1973-08-28 Gabriel Willis Ass Altering the properties of concrete by altering the quality or geometry of the intergranular contact of filler materials
US3917781A (en) * 1969-12-19 1975-11-04 Lester H Gabriel Altering the properties of concrete by altering the quality or geometry of the intergranular contact of filler materials
US3927163A (en) * 1969-01-21 1975-12-16 Gabriel Willis Associates Altering the properties of concrete by altering the quality or geometry of the intergranular contact of filler materials
WO1981003170A1 (fr) * 1980-05-01 1981-11-12 Aalborg Portland Cement Article forme et materiau composite et leur procede de production
JPS63166424A (ja) * 1986-12-27 1988-07-09 Daiyu Kensetsu Kk 自動粒度配合管理装置
WO1991017875A1 (fr) * 1990-05-18 1991-11-28 E. Khashoggi Industries Compositions de ciment agglomere hydrauliquement et procedes de fabrication et d'utilisation associes
WO1992002344A1 (fr) * 1990-08-10 1992-02-20 E. Khashoggi Industries Compositions de ciment de faible densite a liaison hydraulique et procedes pour leur fabrication et leur utilisation
EP0495098A1 (fr) * 1989-09-28 1992-07-22 Hoei Sangyo Kabushiki Kaisha Procede et dispositif de regulation de melanges de materiaux granulaires tels que due sable, de materiaux poudreux tels que du ciment et de liquide
RU2004515C1 (ru) * 1992-08-04 1993-12-15 Sviridov Nikolaj V Бетонна смесь
WO1994004330A1 (fr) * 1992-08-11 1994-03-03 E. Khashoggi Industries Recipients a prise hydraulique
WO1994012328A1 (fr) * 1992-11-25 1994-06-09 E. Khashoggi Industries Compositions a charge elevee de substances inorganiques
WO1994019172A1 (fr) * 1993-02-17 1994-09-01 E. Khashoggi Industries Melanges durcissables hydrauliquement
WO1994020274A1 (fr) * 1993-03-08 1994-09-15 E. Khashoggi Industries Barrieres isolantes a matrice durcissable hydrauliquement

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2250107A (en) * 1939-09-02 1941-07-22 Detroit Edison Co Concrete

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3927163A (en) * 1969-01-21 1975-12-16 Gabriel Willis Associates Altering the properties of concrete by altering the quality or geometry of the intergranular contact of filler materials
US3917781A (en) * 1969-12-19 1975-11-04 Lester H Gabriel Altering the properties of concrete by altering the quality or geometry of the intergranular contact of filler materials
US3754954A (en) * 1971-08-10 1973-08-28 Gabriel Willis Ass Altering the properties of concrete by altering the quality or geometry of the intergranular contact of filler materials
WO1981003170A1 (fr) * 1980-05-01 1981-11-12 Aalborg Portland Cement Article forme et materiau composite et leur procede de production
JPS63166424A (ja) * 1986-12-27 1988-07-09 Daiyu Kensetsu Kk 自動粒度配合管理装置
EP0495098A1 (fr) * 1989-09-28 1992-07-22 Hoei Sangyo Kabushiki Kaisha Procede et dispositif de regulation de melanges de materiaux granulaires tels que due sable, de materiaux poudreux tels que du ciment et de liquide
WO1991017875A1 (fr) * 1990-05-18 1991-11-28 E. Khashoggi Industries Compositions de ciment agglomere hydrauliquement et procedes de fabrication et d'utilisation associes
WO1992002344A1 (fr) * 1990-08-10 1992-02-20 E. Khashoggi Industries Compositions de ciment de faible densite a liaison hydraulique et procedes pour leur fabrication et leur utilisation
RU2004515C1 (ru) * 1992-08-04 1993-12-15 Sviridov Nikolaj V Бетонна смесь
WO1994004330A1 (fr) * 1992-08-11 1994-03-03 E. Khashoggi Industries Recipients a prise hydraulique
WO1994012328A1 (fr) * 1992-11-25 1994-06-09 E. Khashoggi Industries Compositions a charge elevee de substances inorganiques
WO1994019172A1 (fr) * 1993-02-17 1994-09-01 E. Khashoggi Industries Melanges durcissables hydrauliquement
WO1994020274A1 (fr) * 1993-03-08 1994-09-15 E. Khashoggi Industries Barrieres isolantes a matrice durcissable hydrauliquement

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 9414, Derwent World Patents Index; Class L02, AN 94-116188, XP002042996 *
PATENT ABSTRACTS OF JAPAN vol. 012, no. 444 (C - 545) 22 November 1988 (1988-11-22) *
See also references of WO9505350A1 *

Also Published As

Publication number Publication date
EP0714383A1 (fr) 1996-06-05
IL110605A0 (en) 1994-11-11
AU679784B2 (en) 1997-07-10
JPH08511486A (ja) 1996-12-03
WO1995005350A1 (fr) 1995-02-23
ZA945497B (en) 1995-06-07
ZW10394A1 (en) 1994-09-28
CN1100395A (zh) 1995-03-22
CA2168643A1 (fr) 1995-02-23
EG20631A (en) 1999-10-31
CO4520143A1 (es) 1997-10-15
IL110605A (en) 1998-08-16
RU2135427C1 (ru) 1999-08-27
NZ273435A (en) 1997-10-24
BR9407168A (pt) 1996-09-17
AU7670994A (en) 1995-03-14
PE33195A1 (es) 1995-11-23

Similar Documents

Publication Publication Date Title
US5527387A (en) Computer implemented processes for microstructurally engineering cementious mixtures
AU679784B2 (en) Design optimized compositions and processes for microstructurally engineering cementitious mixtures
Phoo-Ngernkham et al. A mix design procedure for alkali-activated high-calcium fly ash concrete cured at ambient temperature
Jiao et al. Mixture design of concrete using simplex centroid design method
Bonavetti et al. Limestone filler cement in low w/c concrete: A rational use of energy
Myadraboina et al. Pozzolanic Index and lime requirement of low calcium fly ashes in high volume fly ash mortar
Makul Combined use of untreated-waste rice husk ash and foundry sand waste in high-performance self-consolidating concrete
Alexandra et al. Mix design of self-compacting concrete with limestone filler versus fly ash addition
Makul et al. Influences of fine waste foundry sand from the automobile engine-part casting process and water-cementitious ratio on the properties of concrete: A new approach to use of a partial cement replacement material
Kwan et al. Packing density and filling effect of limestone fines
CN110186954A (zh) 一种高强度低绝热温升混凝土及其绝热温升值的分析方法
Lotfy Lightweight Self-consolidating Concrete: Statistical Modelling, Mixture Design And PerformanceEvaluation
CN112645621A (zh) 无机增强掺合料、混凝土及其应用
Karim et al. Ready mixed concrete behavior of granulated blast furnace slag contained cement
Meyerson Compressive creep of prestressed concrete mixtures with and without mineral admixtures
GEBEYEHU OPTIMIZATION OF SUPERPLASTICIZER DOSAGE AND EFFECTS WITH LOCALLY PRODUCED CEMENTS ON READY-MIX CONCRETE PROPERTIES
Janamian A comprehensive method for concrete mix design
Fu et al. Expansion characteristics of a compounded-expansive additive and pre-hydrated high alumina cement based expansive additive
Gao Assessing the Compressive Strength and Elastic Modulus of High-Performance GGBS Concrete
Panda et al. Material Design, Additive Manufacturing, and Performance of Cement-Based Materials
Soutsos et al. Portland cements
Jiang Mix Design of Concrete with Manufactured Sand
Chapman et al. Materials of Lightweight Concrete Research
Moes Precast, Prestressed Concrete Made with Alternative Supplementary Cementitious Materials
Nguyen et al. Chloride diffusion resistance of limestone calcined clay cement (LC3) concrete based on calcined clay reactivity

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19960308

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE

A4 Supplementary search report drawn up and despatched

Effective date: 19980210

AK Designated contracting states

Kind code of ref document: A4

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE

17Q First examination report despatched

Effective date: 19990715

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: E. KHASHOGGI INDUSTRIES, LLC

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED

18R Application refused

Effective date: 20011122