WO2000024689A1 - Method for improving a binder having hydraulic properties - Google Patents
Method for improving a binder having hydraulic properties Download PDFInfo
- Publication number
- WO2000024689A1 WO2000024689A1 PCT/NL1999/000659 NL9900659W WO0024689A1 WO 2000024689 A1 WO2000024689 A1 WO 2000024689A1 NL 9900659 W NL9900659 W NL 9900659W WO 0024689 A1 WO0024689 A1 WO 0024689A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- binder
- calcium oxide
- weight
- free calcium
- amount
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0032—Controlling the process of mixing, e.g. adding ingredients in a quantity depending on a measured or desired value
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
- C04B22/08—Acids or salts thereof
- C04B22/14—Acids or salts thereof containing sulfur in the anion, e.g. sulfides
- C04B22/142—Sulfates
- C04B22/143—Calcium-sulfate
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions 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
Definitions
- the invention relates to a method for improving a binder having hydraulic properties, which binder contains at least about five weight . % free calcium oxide.
- free calcium oxide means the molecule CaO, and not - as is usual in the cement literature - the total amount of calcium compounds calculated as converted to CaO.
- the hydraulic properties of the binder are obtained in the present invention with a pozzolanic mate- rial, preferably meta-kaolin.
- a binder of the type mentioned in the preamble is for example known from the publication " Study Environmental Science” , 1991, no. 48, pages 233-242 of Rogic, V. et al . From this publication a binder on basis on fly ash is known, comprising a high percentage free calcium oxide. Therefore, this binder is not considered suitable to act on itself as a mixing compound to prepare a binder having hydraulic properties, and it is aimed for to convert the free calcium oxide by hydratation to make it suitable as a component of a hydraulic product, like masonry cement.
- the binder is processed into a mortar by adding sand and water.
- the free calcium oxide withdraws water from the desired cement hydration-reactions, whereby cal- ciumhydroxide is formed. It seems to be obvious to add the amount of withdrawn water, however this deteriorates the quality of the final mortar obtained. If the ratio wa- ter/binder becomes too high, the final strength of the product obtained with the mortar becomes too low. On the other hand the absence of such an addition of the withdrawn water leads to material which is difficult to process . Another problem is that energy emerges in the reaction of the free calcium oxide with water, whereby the mixture binder/sand/water increases in temperature, leading to undesirable tensions in the mortar which may lead to undesired cracks and fractures.
- This object is achieved according to the present invention by adding to the binder a sulphate compound in a proportion depending on the amount of free calcium oxide in the binder.
- the method for improving the binder starts with a binder comprising at least about 1 weight. % meta-kaolin.
- the sulphate compound is calcium sulphate.
- calcium sulphate means CaS0 4 -2 H 2 0, CaS0 4 -_ H 2 0, CaS0 4 and any other mixture of these sulphates.
- gypsum provides very good results. Gypsum is well available and forms a cheap admixture compound for the improvement of the binder .
- the added amount of sulphate compound is set in the range 15-55 weight . % related to the amount of free CaO in the binder. It appears that, regarding effectivity, optimal results are obtained when the added amount of sulphate compound is set in the range of 20-40 weight . % related to the proportion free CaO in the binder.
- the added amount of sulphate compound is set on 1 weight. %, added with an amount equal to at least a tenth part of the weight percentage free calcium oxide in the binder.
- a binder referred to with sample I and sample II, respectively, and with the infra indicated compound data, is improved according to the present invention by adding gypsum and then processing into a final product by admixture of water and, in certain experiments as illustrated in the following, also sand.
- the processability of sample I and II was examined according to the Vicat-method.
- the amount of water added to the mixture of sample I and II respectively, and gypsum is variated in such a way that penetration of a needle, the so-called Vicat- needle, provides in each case the same value.
- This Vicat- needle has a diameter of 10 mm; the force applied on the needle is about 3 N.
- the needle is placed on the mixture to be examined, which mixture is accepted in a container to a height of 40 mm; the penetration in depth to be obtained amounts in each case to 34 mm + 1 mm.
- Figure 1 and 2 show the results of the need for water related to the amount binder depending on the amount added gypsum to sample I and II, respectively. It appears from the results of the Vicat experiment, that adding of gypsum decreases the need of water of the calcium oxide containing sample I and II respectively, and that despite adding of gypsum the processability can be maintained on a similar level, while the amount of water to be added can be decreased.
- a mixture is formed of the samples I and II (in each case 450 gram) , the amount of gypsum added be- ing a variable, with 1350 gram normsand and 562.5 gram water for sample I and 225 gram water for sample II, and then the so-called " shake measure" (Dutch: schudmaat) , determined according to NEN 3534.
- the shaking measure is a measure well known in the cement technology, and is deter- mined using a little column, which is defined in advance.
- This column of a not yet cured mixture of water/sand/ binder is obtained by filling a mould having a diameter of 100 mm and a height of 50 mm in three steps, which mould is ram down 10 times manually at intervals. Then the shaking table is, after removal of the mould, shaken 50 times with an amplitude of 12 to 13 mm, and it is determined whether the column is broadened at its base.
- a high shake measure (broadening of the base) corresponds with a better flow behaviour, and is thereby a measure for a better processability.
- Figures 5 and 6 show the shaking measure for the samples I and II. These figures show that the shaking measure is improved by adding gypsum while adding the same amount of water. This means that when free calcium oxide is present in the binder, the adding of gypsum allows a better flow behaviour to be obtained at a lower ratio of water/binder.
Abstract
The invention relates to a method improving a binder having hydraulic properties, which binder comprises at least about five weight.% free calcium oxide. To the binder a sulphate compound is added in an amount depending on the amount free calcium oxide in the binder. Further the sulphate compound is calcium sulphate selected from the group comprising of CaSO4.2 H2O, CaSO4.1/2 H2O, CaSO4 and any mixture thereof.
Description
Method for improving a binder having hydraulic properties
The invention relates to a method for improving a binder having hydraulic properties, which binder contains at least about five weight . % free calcium oxide. In this application free calcium oxide means the molecule CaO, and not - as is usual in the cement literature - the total amount of calcium compounds calculated as converted to CaO.
The hydraulic properties of the binder are obtained in the present invention with a pozzolanic mate- rial, preferably meta-kaolin.
A binder of the type mentioned in the preamble is for example known from the publication " Study Environmental Science" , 1991, no. 48, pages 233-242 of Rogic, V. et al . From this publication a binder on basis on fly ash is known, comprising a high percentage free calcium oxide. Therefore, this binder is not considered suitable to act on itself as a mixing compound to prepare a binder having hydraulic properties, and it is aimed for to convert the free calcium oxide by hydratation to make it suitable as a component of a hydraulic product, like masonry cement.
The problem relating to the presence of free calcium oxide in a binder of the type mentioned in the preamble can be summarized as follows.
The binder is processed into a mortar by adding sand and water. The free calcium oxide withdraws water from the desired cement hydration-reactions, whereby cal- ciumhydroxide is formed. It seems to be obvious to add the amount of withdrawn water, however this deteriorates the quality of the final mortar obtained. If the ratio wa- ter/binder becomes too high, the final strength of the product obtained with the mortar becomes too low. On the other hand the absence of such an addition of the withdrawn water leads to material which is difficult to process .
Another problem is that energy emerges in the reaction of the free calcium oxide with water, whereby the mixture binder/sand/water increases in temperature, leading to undesirable tensions in the mortar which may lead to undesired cracks and fractures. Moreover the rise in temperature leads to an acceleration of the cement hy- dratation reactions, having a disadvantageous effect on the processability of the mixture binder/sand/water. In general, these problems are countered by inhibiting as much as possible the presence of free calcium oxide, and by hydration of the small amount free calcium oxide yet present . For example it is known from the French application FR-A-2.642.747 to hydrate a construction material comprising free calcium oxide. These known measures yield a binder comprising less than 1 weight. % free calcium oxide. The above mentioned problems are, in case of such low percentages, reduced to acceptable proportions.
From the European application EP-A-0.346.992 a method is known for the forming of a curable mixture of fly ash comprising free calcium oxide and free CaSO4-0 H20. For the removal of the free calcium oxide the fly ash is mixed with another fly ash which is free of free calcium oxide, and to this mixture water is added, and the mixture is heat-treated. This method results in an artificial grind and does not provide an improved binder.
From the German Offenlegungsschrift DE-A-35 37 812 it is known to produce a hydraulic binder by mixing on the one hand industrial residues comprising a high amount free calcium- and/or magnesium oxide, calcium sulphate and/or -sulphite, and on the other hand latent hydraulic and/of pozzolanic compounds. As an industrial residue fly ash is mentioned.
It is an object of the present invention to improve a binder comprising a weight percentage free calcium oxide of at least 5%, so as to make this binder suitable for processing to a mortar not encountering the known problems as mentioned above.
This object is achieved according to the present invention by adding to the binder a sulphate compound in a proportion depending on the amount of free calcium oxide in the binder. This leads in several regards to improved properties of the binder. It appears that the binder, as improved according the present invention, is better proc- essable because of a better consistency and a delayed start of binding. Furthermore it appears that during the curing of the mixture containing the binder no crack form- ing takes place.
It is preferred that the method for improving the binder starts with a binder comprising at least about 1 weight. % meta-kaolin.
In particular the desired results are obtained according to the present invention, when the sulphate compound is calcium sulphate. Herein calcium sulphate means CaS04-2 H20, CaS04-_ H20, CaS04 and any other mixture of these sulphates. Surprisingly it is found that gypsum provides very good results. Gypsum is well available and forms a cheap admixture compound for the improvement of the binder .
It is mentioned that US-A-5.439.518 describes the recycling of fly ashes in a cement mortar, the fly ashes containing at most 30% CaO. However, this publication does not mention clearly whether free calcium oxide is used. To these fly ashes is added between 10 and 80% gypsum in the form of CaS04- H20 to influence the pressure strength of the material .
It is desirable that the added amount of sulphate compound is set in the range 15-55 weight . % related to the amount of free CaO in the binder. It appears that, regarding effectivity, optimal results are obtained when the added amount of sulphate compound is set in the range of 20-40 weight . % related to the proportion free CaO in the binder.
Further it is preferred that the added amount of sulphate compound is set on 1 weight. %, added with an
amount equal to at least a tenth part of the weight percentage free calcium oxide in the binder.
The present invention will be illustrated in the following referring to the following comparative and non- limiting embodiment.
A binder referred to with sample I and sample II, respectively, and with the infra indicated compound data, is improved according to the present invention by adding gypsum and then processing into a final product by admixture of water and, in certain experiments as illustrated in the following, also sand.
TABLE 1
In table 2, infra, the mixtures prepared with samples I and II are illustrated, together with the obtained data of processability. The column "%" given in table 2 , relates to weight percentage added gypsum related to the total amount of the particular sample and gypsum.
TABLE 2
Next, the crack forming of several mixtures of table 2 are examined. To this end little balls were formed of the respective mixtures, which balls were cured during three days in a closed room. After these three days the little balls were air cured at room temperature.
The results are given in table 3, infra.
TABLE 3
Next, the processability of sample I and II was examined according to the Vicat-method. In this measuring method the amount of water added to the mixture of sample I and II respectively, and gypsum is variated in such a way that penetration of a needle, the so-called Vicat- needle, provides in each case the same value. This Vicat- needle has a diameter of 10 mm; the force applied on the needle is about 3 N. The needle is placed on the mixture to be examined, which mixture is accepted in a container
to a height of 40 mm; the penetration in depth to be obtained amounts in each case to 34 mm + 1 mm.
Figure 1 and 2 show the results of the need for water related to the amount binder depending on the amount added gypsum to sample I and II, respectively. It appears from the results of the Vicat experiment, that adding of gypsum decreases the need of water of the calcium oxide containing sample I and II respectively, and that despite adding of gypsum the processability can be maintained on a similar level, while the amount of water to be added can be decreased.
Further it was examined on which moment the start of binding in samples I and II, respectively, was initiated depending on the amount of gypsum added to the sam- pie. The start of binding was examined with a Vicat-needle having a diameter of 1.13 mm, by applying a pressure of 3 N on the needle. This more narrow needle (relating to Vi- cat-processability) contacts at first the bottom of a mould comprising a mortar sample having a height of 40 mm. The moment in time when this more narrow needle stops on a distance of 3 + 1 mm from the bottom is called the 'start of binding' (thus, at a netto penetration of this more narrow needle of 37 ± 1 mm) . The results are shown in Figures 3 and 4. From these results it appears that the add- ing of gypsum delays the start of binding of the material containing calcium oxide, whereby the rise of the development of tensions and cracks is decreased.
Further, a mixture is formed of the samples I and II (in each case 450 gram) , the amount of gypsum added be- ing a variable, with 1350 gram normsand and 562.5 gram water for sample I and 225 gram water for sample II, and then the so-called " shake measure" (Dutch: schudmaat) , determined according to NEN 3534. The shaking measure is a measure well known in the cement technology, and is deter- mined using a little column, which is defined in advance. This column of a not yet cured mixture of water/sand/ binder is obtained by filling a mould having a diameter of
100 mm and a height of 50 mm in three steps, which mould is ram down 10 times manually at intervals. Then the shaking table is, after removal of the mould, shaken 50 times with an amplitude of 12 to 13 mm, and it is determined whether the column is broadened at its base. A high shake measure (broadening of the base) corresponds with a better flow behaviour, and is thereby a measure for a better processability.
Figures 5 and 6 show the shaking measure for the samples I and II. These figures show that the shaking measure is improved by adding gypsum while adding the same amount of water. This means that when free calcium oxide is present in the binder, the adding of gypsum allows a better flow behaviour to be obtained at a lower ratio of water/binder.
Claims
1. Method for improving a binder having hydraulic properties, which binder comprises at least about five weight. % free calcium oxide, characterized, in that to the binder is added a sulphate compound in a proportion that depends on the proportion free calcium oxide in the binder.
2. Method according to claim 1, characterized, in that a binder comprising at least about 1 weight . % meta- kaolin is used.
3. Method according to claim 1 or 2 , characterized, in that the sulphate compound is calcium sulphate selected from the group comprising CaS04-2 H20, CaS04-1 H20, CaS04 and any mixture thereof .
4. Method according to one of the claims 1, 2 or 3, characterized, in that the sulphate compound is gypsum.
5. Method according to one of the claims 1-4, characterized, in that the added amount of sulphate compound is set on at least 15 weight . % and at most 55 weight . % related to the content free CaO in the binder.
6. Method according to claim 5, characterized, in that the added amount sulphate compound is set in the range 20-40 weight. % related to the content free CaO in the binder.
7. Method according to claim 5 or 6 , character- ized, in that the added amount sulphate compound is added in the form of gypsum and is set on 1 weight. %, together with an amount equal to at least a tenth part of the weight percentage of free calcium oxide in the binder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU11881/00A AU1188100A (en) | 1998-10-26 | 1999-10-25 | Method for improving a binder having hydraulic properties |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL1010396A NL1010396C2 (en) | 1998-10-26 | 1998-10-26 | Method for improving a binder with hydraulic properties. |
| NL1010396 | 1998-10-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2000024689A1 true WO2000024689A1 (en) | 2000-05-04 |
Family
ID=19768022
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/NL1999/000659 WO2000024689A1 (en) | 1998-10-26 | 1999-10-25 | Method for improving a binder having hydraulic properties |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU1188100A (en) |
| NL (1) | NL1010396C2 (en) |
| WO (1) | WO2000024689A1 (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4211571A (en) * | 1977-08-31 | 1980-07-08 | Intong Ab | Method of producing gas concrete |
| SU1350138A1 (en) * | 1984-11-05 | 1987-11-07 | Красноярский инженерно-строительный институт | Binder |
| US5439518A (en) * | 1993-01-06 | 1995-08-08 | Georgia-Pacific Corporation | Flyash-based compositions |
| JPH0952746A (en) * | 1995-08-18 | 1997-02-25 | Denki Kagaku Kogyo Kk | Irritant for blended cement and blended cement composition |
| EP0858978A2 (en) * | 1997-02-12 | 1998-08-19 | Mineral Resource Technologies, LLC | Blended hydraulic cement |
-
1998
- 1998-10-26 NL NL1010396A patent/NL1010396C2/en not_active IP Right Cessation
-
1999
- 1999-10-25 WO PCT/NL1999/000659 patent/WO2000024689A1/en active Application Filing
- 1999-10-25 AU AU11881/00A patent/AU1188100A/en not_active Abandoned
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4211571A (en) * | 1977-08-31 | 1980-07-08 | Intong Ab | Method of producing gas concrete |
| SU1350138A1 (en) * | 1984-11-05 | 1987-11-07 | Красноярский инженерно-строительный институт | Binder |
| US5439518A (en) * | 1993-01-06 | 1995-08-08 | Georgia-Pacific Corporation | Flyash-based compositions |
| JPH0952746A (en) * | 1995-08-18 | 1997-02-25 | Denki Kagaku Kogyo Kk | Irritant for blended cement and blended cement composition |
| EP0858978A2 (en) * | 1997-02-12 | 1998-08-19 | Mineral Resource Technologies, LLC | Blended hydraulic cement |
Non-Patent Citations (3)
| Title |
|---|
| CHEMICAL ABSTRACTS, vol. 126, no. 19, 12 May 1997, Columbus, Ohio, US; abstract no. 254537, MORIOKA, MINORU ET AL: "Activator for blended cement and blended cement compositions" XP002130233 * |
| DATABASE WPI Section Ch Week 198823, Derwent World Patents Index; Class A93, AN 1988-159658, XP002130234 * |
| MATKOVIC B ET AL: "Hydrated fly ash with SiO2 fume and/or Portland cement addition. Reactions in pastes and strength development in mortars", CEM CONCR RES;CEMENT AND CONCRETE RESEARCH MAY 1990, vol. 20, no. 3, May 1990 (1990-05-01), pages 475 - 483, XP000874750 * |
Also Published As
| Publication number | Publication date |
|---|---|
| AU1188100A (en) | 2000-05-15 |
| NL1010396C2 (en) | 2000-04-27 |
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