GB2359550A - Retarder for calcium sulfoaluminate cements - Google Patents
Retarder for calcium sulfoaluminate cements Download PDFInfo
- Publication number
- GB2359550A GB2359550A GB0109340A GB0109340A GB2359550A GB 2359550 A GB2359550 A GB 2359550A GB 0109340 A GB0109340 A GB 0109340A GB 0109340 A GB0109340 A GB 0109340A GB 2359550 A GB2359550 A GB 2359550A
- Authority
- GB
- United Kingdom
- Prior art keywords
- carboxylic acid
- calcium
- alkyl carboxylic
- phosphono
- sulfbaluminate
- 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.)
- Withdrawn
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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
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/003—Phosphorus-containing compounds
-
- 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
- C04B28/06—Aluminous cements
- C04B28/065—Calcium aluminosulfate cements, e.g. cements hydrating into ettringite
-
- 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
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/20—Retarders
- C04B2103/22—Set retarders
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
A set-retarding admixture for calcium sulfoaluminate cements, comprising at least one phosphorus alkyl carboxylic acid and/or salt thereof, the phosphono alkyl carboxylic acid having the structure <EMI ID=1.1 HE=32 WI=28 LX=545 LY=711 TI=CF> <PC>wherein R is independently selected from -H, <EMI ID=1.2 HE=18 WI=28 LX=1290 LY=958 TI=CF> <PC>, or <EMI ID=1.3 HE=27 WI=30 LX=525 LY=1148 TI=CF> <PC>and n is an integer from 3 to 6, with the proviso that at least one R is PO(OH)<SB>2</SB>. The admixture may also contain a carboxylic acid or a salt thereof.
Description
MBC-0353/Div 2359550 1 RETARDER FOR CALCIUM SULF0ALUMINATE CEMENTS
FIELD OF THE INVENTION
The present invention is. directed to a retarder for calcium sulfoaluminate cements. More particularly, the present invention is directed to a retarder for calcium sulfoaluminate cements comprising phosphono alkyl carboxylic acid and/or its salts.
BACKGROUND OF THE INVENTION
Calcium sulfbaluminate (CSA) cements generally comprise cements containing the components 4Ca.0.3A1203.SO3, CaSO4, and CaO. When CSA cements are hydrated, ettringite is formed by the following reaction:
4CaO.3A1203'SO3 + 8CaSO4 + 6CaO +93H20 --> 3(CaOcAI203-3CaSO4.3 1H20) The formation of ettringite is very fast. This reaction provides for high early compressive strength of a cementitious formulation; however, this reaction causes the loss of workability of the cementitious formulation. To slow down the reaction and provide increased workability, retarders have been added to slow the hydration reaction in CSA cements. Typically, the retarders chelate the calcium and thus slow the hydration reaction.
While it has been known to use carboxylic acids, such as citric acid or tartaric acid, as retarders in calcium sulfbaluminate cements, these carboxylic acids require a large dose to be effective at retarding the reaction. At higher doses, not only is the set retarded, but the compressive strength of a resulting cement is also reduced. Increased workability is achieved at the cost of decreased compressive strengtIL To overcome the problems with decreased compressive strength, carboxylic acids have been used in combination with other additives to seek to recapture some of the lost compressive strength. It has also been known to use phosphono butane tricarboxylic acids and phosphono aliphatic carboxylic acids as set retarders, but not in connection with calcium sulfoaluminate cements.
MBC-0353/Div 2 What is needed in the industry is a set retarder for calcium sulfoaluminate cements that retards the set of the cement without a significant reduction in the compressive strength of a resulting cement.
It is therefore an object of the present invention to provide an admixture that retards the hydration of calcium sulfbaluminate cements without a significant reduction in the compressive strength of the cement.
It is another object of the present invention to provide a calcium sulfbaluminate cement formulation containing a retarder that retards the hydration of the calcium sulfoaluminate cement without a significant reduction in the compressive strength of the cement.
SUMMARY OF THE RWENTION
The present invention is directed to a set retarding admixture for calcium sulfoaluminate cements comprising at least one of a phosphono alkyl carboxylic acid and a salt of a phosphono alkyl carboxylic acid.
The present invention is also directed to a cementitious formulation comprising a calcium sulfbaluminate cement and a retarder, wherein the retarder comprises a component being at least one of a phosphono alkyl carboxylic acid and a salt of a phosphono alkyl carboxylic acid.
The present invention is also directed to a method of retarding the set of a calcium sulfbaluminate cementitious formulation without substantially reducing achievable compressive strength, comprising providing in said cementitious formulation, a retarder comprising a component being at least one of a phosphono alkyl carboxylic acid and a salt of a phosphono alkyl carboxylic acid, and wherein the calcium sulfbaluminate cementitious formulation comprises a calcium sulfbaluminate cement.
MBC-0353/Div 3 BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a graph comparing the retarding properties of selected retarders for calcium sulfoaluminate cements.
Figure 2 is a graph of setting time versus dosage of the retarder and a graph of the two hour compressive strength versus dosage of the retarder.
DETAILED DESCRIPTION OF THE INVENTION
For simplification in writing, as used herein, the term acid/salt refers to the acid and/or the salt form of the chemical.
One embodiment of the present invention is directed to a set retarding admixture 15 for calcium sulfoaluminate cements comprising a component that is at least one of a phosphono alkyl carboxylic acid and a salt of a phosphono alkyl carboxylic acid.
The salt of the phosphono alkyl carboxylic acid is selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, ammonium, and 20 mixtures thereof. The preferred salts are sodium and potassium.
The preferred phosphono alkyl carboxylic acid/salt is 2-phosphono-1,2,4butane tricarboxylic acid (PBTC).
The phosphono alkyl carboxylic acid has the general structure shown below:
MBC-0353/Div 4 R 1 G R 1 R n 0 11 wherein R is independently selected from -H, -C-OH or R 1 H1 -,, 0---- P' 0 H 1 0 and n is an integer from 3 to 6, with the proviso that at least one R is PO(OH)2.
The preferred 2-phosphono-1,2,4-butane tricarboxylic acid is represented by the following structure:
11 0 0 0 11 11 HO-C C-OH C-OH 1 1 H2 1 H2C-C-C-CH2 1 P"'OH HO 11 0 It has been found that the acid form of the phosphono alkyl carboxylic acid is generally more effective at retarding the calcium sulfbaluminate cement than are the corresponding salts.
Another embodiment of the present invention is directed to a Cementitious formulation comprising a calcium sulfoaluminate cement and a retarder, wherein the retarder comprises a component being at least one of a phosphono alkyl carboxylic acid and a salt of a phosphono alkyl carboxylic, acid. The salt of phosphono alkyl carboxylic MBC-0353/Div acid is selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, ammonium, and mixtures thereof The preferred salts are sodium and potassium.
The preferred phosphono alkyl carboxylic acid is 2-phosphono-1,2,4-butane tricarboxylic acid.
The retarder is present in the cementitious formulation in an amount from greater than 0% to about 1% based on the dry weight of the calcium sulfoalurninate cement. Preferably, the retarder is present in an amount of from about 0. 2% to about 0.8% based on the dry weight of the calcium sulfbaluminate cement.
The phosphono alkyl carboxylic acid/salt component of the retarder is present in the cementitious formulation in an amount from greater than 0% to about 0.4% based on the dry weight of the calcium sulfbaluminate cement. Preferably, the phosphono alkyl carboxylic acid/salt component is present in an amount from about 0.05% to about 0.3% based on the dry weight of the calcium sulfoaluminate cement.
The amount of phosphono alkyl carboxylic acid/salt is preferably kept low because of its low threshold value. The threshold value is the minimum amount needed to be effective. Carboxylic acids/salts have a higher threshold value as compared to a phosphono alkyl carboxylic acid/salt. When carboxylic acids/salts are used alone at high levels, not only is the cement retarded, but also the compressive strength of a resulting cement is reduced. The effective dose of phosphono alkyl carboxylic acid/salt is lower than the effective dose of a carboxylic acid/salt, which results in retardation of the calcium sulfbaluminate cement without a significant reduction in the compressive strength of a resulting cement.
In comparison, it has also been found that conventional chelators, such as hydroxyethylidenediphosphonic acid (HEDP) and ethylenediaminetetraacetic acid (EDTA) have no ability to retard the formation of ettringite in calcium sulfoaluminate cements.
MBC-0353 iv 6 The cementitious formulation of the present invention can further comprise other cements used in combination with the calcium sulfbaluminate cement. Examples of these other cements include, but are not limited to, portland, pozzolanic, and mixtures thereof These other cements can replace up to about 70 to 80% of the calcium sulfoaluminate cement, without altering the effect of the retarder of the present invention.
The cementitious formulation of the present invention may further comprise aggregate. Examples of aggregate include, but are not limited to, silica, quartz, crushed round marble, glass spheres, granite, limestone, calcite, feldspar, alluvial sands, any other sands, any other durable aggregate, and mixtures thereof.
The cementitious formulation of the present invention may additionally comprise any cement additive that does not adversely affect the advantageous results obtained by the present invention. Examples of additives include, but are not limited to, dispersants, defoaming agents, air-entraining or air detraining agents, corrosion inhibitors, water reducing agents, pigments, and mixtures thereof The cementitious formulation of the present invention is activated upon the addition of water. The water to cement ratio (W/C) generally ranges from about 0.28 to about 0.5 based on the dry weight of all cements in the cementitious formulation.
Another embodiment of the present invention provides a method of retarding the set of a calcium sulfbaluminate cementitious formulation without substantially reducing achievable compressive strength. The method includes providing in the cementitious formulation, a retarder comprising at least one of a phosphono alkyl carboxylic, acid and a salt of a phosphono alkyl carboxylic acid. The calcium sulfbaluminate cementitious formulation contains a calcium sulfbaluminate cement and may contain other cements, aggregates, and additives that do not adversely affect the advantageous results obtained by the present invention. Water is added to the calcium sulfbaluminate cementitious formulation to cause the formulation to set.
MBC-0353/Div 7 The preferred phosphono alkyl carboxylic acid is 2-phosphono-1,2,4-butane tricarboxylic acid.
The retarder in the method of the present invention may further comprise a second component that is at least one of a carboxylic acid and a salt of a carboxylic acid, as described above.
EXAMPLES
Exam-ple 1 A comparison of set retarders is performed. The set of a control mixture of calcium sulfbaluminate cement is compared to those of calcium sulfbaluminate cement mixtures containing tartaric acid at 0.5%, citric acid at 0.5%, and 2-phospono-1,2,4butane tricarboxylic acid (BAY111BIT (trade mark) AM from Bayer Corporation, Pittsburgh, Pennsylvania) at 1% based on the dry weight of the calcium sulfbaluminate cement. The calcium sulfbaluminate cement used is sold under the trademark ULTIMAX from Ultimax Corp., Huntington Beach, California. The results of the comparison, determined by calorimetry, are shown in Figure 1. The units of measurement in Figure 1 are gg/calorie/second which is proportional to the heat of hydration of the samples.
As shown in Figure 1, it can be seen that all three acids reduce the intensity, but not the sharpness of the first major peak of the pure calcium sulfbaluminate cement. In theory, this peak indicates the heat release due to the setting of the cement. The second peak in the curve is more rounded and is believed to indicate an increase in strength development. In all cases, the acids reduce the intensity of this curve and significantly broaden the curve out. The tartaric acid and citric acid behave comparably, while the height for the PBTC curve is maintained over a greater time. It is believed that this is why PBTC has higher strength development for a given retardation.
MBC-0353/Div ExIMple 2 8 Mixtures of calcium sulfbaluminate cements are prepared with various combinations of the retarders of the present invention. The setting time and the 2 hour compressive strength are measured.
Cementitious Formulation Calcium Sulfbaluminate Cement (ULTEVIAX) Dry Sand water water to cement ratio Components added by weight percent of dry cement Component A: 2-phospono- 1,2,4-butane tricarboxylic acid Component B: Tartaric Acid The results of the above mixtures are listed below in Table 1. Table 1 1600 g (32%) 3400 g (68%) 480 mI 0.3 Mix Component (wt.%) Setting 2 Hour Compressive Strength Number (A) (B) Time (Mpa) (min) 1 0.0 0.0 17 41.06 2 0.1 0.0 35 38.45 3 0.4 0.0 38 3.03 4 0.0 0.2 25 26.55 0.0 0.8 40 1.20 6 0.2 0.1 40 19.77 7 0.1 0.2 41 20.62 Example 3
The dosages of PBTC and tartaric acid are varied to determine the set time of a calcium sulfbaluminate cement. ULTEVIAX cement is used.. Also, the 2 hour compressive strength of the mixture with PBTC and the mixture with tartaric acid is measured. The results are shown in Figure 2.
MBC-0353/Div 9 As is shown in Figure 2, as the dosage of retarder increases, the 2 hour compressive strength decreases showing that the mixture is retarded and not yet fully set.
It should be appreciated that the present invention is not limited to the specific embodiments described above, but includes variations, modifications and equivalent embodiments defined by the following claims.
MBC-0353/Div
Claims (7)
1. A set retarding admixture for calcium sulfbaluminate cements comprising at least one of a phosphono alkyl carboxylic acid and a salt of a phosphono alkyl carboxylic acid, wherein the phosphono alkyl carboxylic acid has the general structure shown below:
R 1 R G 1 R n R 11 wherein R is independently selected from -H, -C-OH or 1 p H 0--' 11 OH D and n is an integer from 3 to 6, with the proviso that at least one R is PO(OH)2.
2.
An admixture according to claim 1, wherein the phosphono alkyl carboxylic acid is 2-phosphono-1,2,4-butane tricarboxylic acid.
3. An admixture according to claim 1 or claim 2, wherein the salt of a phosphono alkyl carboxylic acid is selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, ammonium, and mixtures thereof.
4.
A cementitious formulation comprising a calcium sulfbaluminate cement and a retarder, wherein the retarder comprises a component being at least one of a phosphono alkyl carboxylic acid and a salt of a phosphono alkyl carboxylic acid, and wherein the phosphono alkyl carboxylic acid has the general structure shown below:
MBC-0353/Div R 1 R- fX R n 0 11 wherein R is independently selected from -H, -C-OH, or 1 p H 0--"' 1 1" 0 H 0 and n is an integer from 3 to 6, with the proviso that at least one R is PO(OH)2.
5. A cementitious formulation according to claim 4, wherein the component is present in an amount from greater than 0% to about 0.4% based on the dry weight of the calcium sulfbaluminate cement.
6. A cementitious formulation according to claim 5, wherein the salt of phosphono alkyl carboxylic acid is selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, ammonium, and mixtures thereof.
7. A method of retarding the set of a calcium sulfbaluminate cementitious formulation without substantially reducing achievable compressive strength, comprising providing in said cementitious formulation, a retarder comprising a component being at least one of a phosphono alkyl carboxylic acid and a salt of a phosphono alkyl carboxylic acid, and wherein the calcium sulfoaluminate cementitious formulation comprises a calcium sulfbaluminate cement, and wherein the phosphono alkyl carboxylic acid has the general structure shown below:
MBC-0353/Div 12 R 1 R cR 1 R n wherein R is independently selected from -H, -C-OH or 0 1 1-11 P'- HO 11 OH 0 and n is an integer from 3 to 6, with the proviso that at least one R is PO(OH)2.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US12243299P | 1999-03-02 | 1999-03-02 | |
| GB0004725A GB2347415A (en) | 1999-03-02 | 2000-02-29 | Set-retarding admixture for calcium sulfoaluminate cements |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0109340D0 GB0109340D0 (en) | 2001-05-30 |
| GB2359550A true GB2359550A (en) | 2001-08-29 |
Family
ID=26243757
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0109340A Withdrawn GB2359550A (en) | 1999-03-02 | 2000-02-29 | Retarder for calcium sulfoaluminate cements |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2359550A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102617061A (en) * | 2012-03-21 | 2012-08-01 | 中建商品混凝土有限公司 | Ultra retarder for concrete and preparation method for ultra retarder |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0508158A2 (en) * | 1991-04-12 | 1992-10-14 | Sika AG, vorm. Kaspar Winkler & Co. | Set retarder for wet spraying |
| US5398759A (en) * | 1993-12-21 | 1995-03-21 | Halliburton Company | Set retarded ultra fine cement compositions and methods |
| GB2327417A (en) * | 1997-07-22 | 1999-01-27 | Albright & Wilson Uk Ltd | Cement setting modifiers |
-
2000
- 2000-02-29 GB GB0109340A patent/GB2359550A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0508158A2 (en) * | 1991-04-12 | 1992-10-14 | Sika AG, vorm. Kaspar Winkler & Co. | Set retarder for wet spraying |
| US5398759A (en) * | 1993-12-21 | 1995-03-21 | Halliburton Company | Set retarded ultra fine cement compositions and methods |
| GB2327417A (en) * | 1997-07-22 | 1999-01-27 | Albright & Wilson Uk Ltd | Cement setting modifiers |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102617061A (en) * | 2012-03-21 | 2012-08-01 | 中建商品混凝土有限公司 | Ultra retarder for concrete and preparation method for ultra retarder |
| CN102617061B (en) * | 2012-03-21 | 2013-10-02 | 中建商品混凝土有限公司 | Ultra retarder for concrete and preparation method for ultra retarder |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0109340D0 (en) | 2001-05-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |