GB1575450A - Process and composition for accelerating the setting of portland cement compositions - Google Patents
Process and composition for accelerating the setting of portland cement compositions Download PDFInfo
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- GB1575450A GB1575450A GB7634/77A GB763477A GB1575450A GB 1575450 A GB1575450 A GB 1575450A GB 7634/77 A GB7634/77 A GB 7634/77A GB 763477 A GB763477 A GB 763477A GB 1575450 A GB1575450 A GB 1575450A
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- 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
- C04B28/04—Portland cements
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Abstract
The hardening time of Portland cement masses is shortened by addition of an alpha -hydroxycarbonyl compound. Together with the alpha -hydroxycarbonyl compound or water-soluble salts thereof, a water-soluble carbonate is added.
Description
(54) A PROCESS AND COMPOSITION FOR ACCELERATING THE SETTING
OF PORTLAND CEMENT COMPOSITIONS
(71) We, SIKA FINANZ AG, a Swiss Company, of Baarerstrasse 12, 6300 Zug,
Switzerland do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:
The invention relates to a process and composition for accelerating the setting of portland cement compositions, for example concretes and mortars containing portland cement.
Additivies for modifying the setting time and other properties of portland cement compositions have been employed virtually since the beginning of cement technology in the 1870's, and the history of such additives is set forth in detail in the complete specification of our U.K. Patent Specification Nos. 1,522,501 and 1,522,502.
). In the aforesaid complete specification, it is shown that previously-known additivies are either inadequate for certain applications (such as shotcreting) because they fail to accelerate the setting of the composition sufficiently or else reduce the ultimate strength of the set composition too much. The specification also discloses that certain a-hydroxycarbonyl compounds can be used to produce portland cement compositions having very short setting times and high ultimate strength. The setting times of the portland cement compositions described and claimed in the specification, as measured by the Proctor Needle
Test (carried out in accordance with ASTM C 403), are often less than 15 minutes and sometimes less than 5 minutes.
For many applications other than shotcreting, such extremely short setting times are a disadvantage because they do not permit enough time for mixing and applying the cement.
For example, it may take thirty minutes to mix, apply and smooth a concrete patch to repair a pothole in a road, so that concrete with a much shorter setting time would be unsuitable for this application.
Whilst it is normally possible to obtain setting times longer than fifteen minutes by carefully selecting the concentration of the oi-hydroxy-carbonyl accelerator used in according with the aforementioned U.S. Patent Specification Nos. 1,522,501 and 1,522,502, such a procedure is not always practical since the setting time may vary very rapidly with accelerator concentration; for example, in mortars having a setting time of more than a few minutes, the variation of setting time with sodium hydroxyacetate concentration is so rapid as to preclude obtaining uniform setting times under commercial production conditions.
The setting times of the compositions also vary with cement-water ratios and other parameters, thus further complicating the attainment of uniform setting times of sufficient magnitude.
We have now discovered that if there is added to a portland cement composition both an a-hydroxy-carbonyl compound and a water-soluble sodium or potassium carbonate compound, the setting time of the composition is reduced to a value which makes the composition useful for many applications.
Accordingly the present invention provides a process for accelerating the setting time of a predetermined quantity of a portland cement composition for a predetermined watercement ratio by admixing with the composition an amount of a chemical admixture so as to produce an accelerated portland cement composition, said portland cement composition having for said predetermined water-cement ratio, in the absence of said admixture, a final setting time as measured by the Vicat Needle test corresponding to a first control setting time, said chemical admixture containing:: (a. 1) a first amount of an a-hydroxy carbonyl compound selected from the group consisting of hydroxyacetic acid, lactic acid, 2-methyllactic acid, dl-mandelic acid and their water-soluble salts, a control sample of the portland cement composition and the a-hydroxy carbonyl compound in proportions equivalent to the ratio of the predetermined quantity of the portland cement composition to the first amount of a-hydroxy carbonyl compound, having, at said predetermined water-cement ratio, a final setting time as measured by the
Vicat Needle test corresponding to a second control setting time, the first amount of a-hydroxy carbonyl compound being sufficient to accelerate the setting time of the predetermined quantity of portland cement composition so that the second control setting time is shorter than the first control setting time; and
(a.2) a second amount of a water-soluble carbonate compound selected from the group consisting of sodium carbonate and potassium carbonate; and optionally
(a.3)a third amount of a water-soluble organic retardant selected from the group consisting of retarding organic compounds having a plurality of hydroxy groups, citric acid, and the sodium, potassium and calcium salts of citric acid; said accelerated portland cement composition having, for said predetermined water-cement ratio, a final setting time measured by the Vicat Needle test corresponding to a test setting time, said amounts of the components of the chemical admixture being effective in combination to accelerate the setting time of the composition such that said test setting time is shorter than said first control setting time, the only constituents of the accelerated portland cement composition capable of appreciably affecting the setting time of a said portland cement composition being the carbonate compound, the a-hydroxy carbonyl compound, and said optional organic retardant, the portland cement, and, where present, water.
The invention also provides an admixture for use in a process of the invention, the admixture consisting essentially of a mixture of:
(a) a first amount of an a-hydroxy carbonyl compound selected from the group consisting of dl-mandelic acid and the water-soluble salts of hydroxyacetic acid, lactic acid, 2-methyllactic acid and dl-mandelic acid;
(b) a second amount of water-soluble carbonate compound selected from the group consisting of sodium carbonate and potassium carbonate; and
(c) a third amont of a water-soluble organic retardant selected from the group consisting of retarding organic compounds having a plurality of hydroxy groups, citric acid, and the sodium, potassium, and calcium salts of citric acid.
In a further aspect the present invention provides a fast-setting premixed portland cement composition produced by a process of the invention which composition consists essentially of:
(a) portland cement;
(b) aggregate;
(c) a first amount of a-hydroxy carbonyl compound selected from the group consisting of dl-mandelic acid and the water-soluble salts of hydroxyacetic acid, lactic acid, 2-methyllactic acid, and dl-mandelic acid, the first amount being sufficient to accelerate the portland cement and aggregate mixture; and
(d) a second amount of water-soluble carbonate compound selected from the group consisting of sodium carbonate and potassium carbonate; and optionally
(e) a third amount of water-soluble organic retardant selected from the group consisting of retarding organic compounds having a plurality of hydroxy groups, citric acid, and the sodium potassium, and calcium salts of citric acid; the first and the second amounts together with the optional third amount being effective in combination to accelerate the portland cement and aggregate mixture, essentially the only constituents of the accelerated portland cement composition capable of affecting the setting time of a said portland cement composition being the hydroxy carbonyl compound, the carbonate compound and the portland cement, and said optional organic retardant.
For the avoidance of doubt it should be noted that the expression "cement composition" as used herein includes compositions containing cement with and without aggregate, and with and without water. Like expressions should be construed correspondingly.
As is pointed out in the complete specification of our aforementioned U.K. Patent
Specification Nos. 1,522,501 and 1,522,502, it is difficult to make generalizations about the effects of broad classes of compounds on the setting times of portland cement compositions.
The problems of making such generalizations are compounded if more than one additive is used and each additive has a differing effect on the setting time. In general, it is not possible to decide if any particular mixture of additives will accelerate or retard the setting rate of any given composition.
The difficulties in making such predictions stem from the fact that the changing of setting times is a catalytic process and, as in many other fields of chemistry, the catalytic mechanism involved is poorly understood. Even the basic reactions involved in the setting of the compositions are not fully understood and without an understanding of the catalytic process, theoretical prediction of the effect of mixtures of additives is impossible. Thus, to determine the effect of such mixtures, resort has to be had to empirical tests.
Sodium carbonate is known to accelerate the setting of portland cement compositions when used alone. Thus "The Chemistry of Cement and Concrete" by Lea and Desch (Edward Arnold, 1956) states that the addition of 1 to 2% alkali metal carbonate to such compositions reduces the setting time thereof to a few minutes. It is thus very surprising that the addition of both a water-soluble carbonate compound and an a-hydroxy-carbonyl compound to a portland cement composition should accelerate the setting of the composition less than the latter compound when used alone.Needless to say, the setting time of a composition to which the two compounds have been added is still substantially shorter than one to which no accelerators have been added, and it has also been found that the early strength development of a composition accelerated with both compounds is more rapid than that of unaccelerated compositions.
The water-soluble carbonate compound used in the process and composition of the present invention is sodium or potassium carbonate, the former being preferred on economic grounds. The carbonate compound is preferably present in an amount of from 0.06 to 2 percent by weight of the cement, though the amount used will naturally vary with the desired setting time. Preferably, the a-hydroxy-carbonyl compound used is hydroxyacetic acid, lactic acid, 2-methyllactic acid, dl-mandelic acid or the sodium, potassium, calcium, lithium, zinc or triethanolamine salt of one of these acids, the especially preferred compound being sodium hydroxyacetate. It is preferred that the amount of a-hydroxycarbonyl compound added be from 0.06 to 5 percent by weight of the cement, though again the amount used will vary with the desired setting time.
The use of a combination of a water-soluble sodium or potassium carbonate compound and an a-hydroxy-carbonyl compound as an additive in portland cement compositions reduces the dependency of setting time on additive concentration, especially for setting times which are only a few minutes longer than those resulting from the use of the a-hydroxy-carbonyl compound alone. At longer setting times, however, the setting times of compositions accelerated with the mixture of the two compounds are somewhat erratic and concentration-dependent. This leads to difficulties in producing mortars and other compositions with predictable setting times, and also renders it difficult to produce large batches of compositions all parts of which have the same setting time.We have found that longer setting times, which are less dependent on additive concentration, can be achieved if there is added to the composition of the invention or to the portland cement composition a water-soluble organic compound containing a plurality of hydroxyl groups, and preferably selected from the group consisting of gluconic acid, lignosulphonic acid, heptogluconic acid and the sodium, potassium and calcium salts of these acids. The especially preferred polyhydroxyl compound is sodium gluconate, and it is preferred that the water-soluble compound containing a plurality of hydroxyl groups comprise from 0.008 to 3 percent by weight of the cement.Very low concentrations of polyhydroxyl compound have been found to have surprisingly large effect in lengthening the setting time and reducing the additive concentration dependence of portland cement compositions accelerated with the mixture of water-soluble carbonate and a-hydroxy-carbonyl compound in accordance with the invention. Polysaccharides may also be used as the polyhydroxyl compounds. Beneficial effects similar to those discussed above for polyhydroxyl compounds can also be obtained by using the monohydroxyl compound citric acid or its sodium potassium or calcium salts.
The above preferred percentage composition ranges for the constituents specified correspond approximately to a weight ratio of the second amount to the first amount of 0.01 to 33 and of the third amount to the second amount of 0.004 to 50.
The setting time of a portland cement composition accelerated in accordance with the invention will vary with a number of factors including the exact compositions of the cement composition and the additive, the water/cement ratio, the nature and quantity of the aggregate used, the order in which the constituents are mixed and the temperature and other conditions under which mixing is effected. However, the necessary amounts of the additives required can be established by simple empirical tests.
Preferably, the additives used in accordance with the invention are selected so that an additive mixture to be added to the cement composition is of substantially neutral pH, so that the additive mixture can be handled without the special precautions required for certain highly caustic prior-art mixtures.
Portland cement compositions accelerated in accordance with the present invention do not react with ferrous metal and do not promote the formation of bimetallic cells where two different metals are joined or lie adjacent one another. Thus, the compositions may safely be used to form reinforced and prestressed concretes as well as in other applications involving a cement, mortar or concrete/metal interface.
The invention naturally extends to a portland cement composition accelerated by a process of the invention, especially when set.
As stated above, it is surprising that the setting time of a portland cement composition accelerated with a mixture of a water-soluble sodium or potassium carbonate compound and an a-hydroxy-carbonyl compound should be longer than that of one accelerated with the latter compound alone, having regard to the fact that the carbonate compound itself is an accelerator when used alone, and certainly this result could not have been predicted in advance. The explanation for this result is believed to be as follows, though it should be noted that the invention is in no way limited by this belief.
Portland cement normally comprises three principle components, namely C3A (tricalcium aluminate), C3S (tricalcium silicate) and C2S (dicalcium silicate), and these three components harden at differing rates; in addition, the three components are affected differently by additives. Since the C3A component hardens most rapidly, it is the hardening of this component which determines the setting time of the cement composition. The early strength development, on the other hand, is due mainly to the hardening -of the C3S component. Since a-hydroxy-carbonyl compounds-accelerate both setting time and early strength development, they apparently accelerate the setting of both C3A and C3S.
However, water-soluble sodium or potassium carbonate compounds appear to accelerate the setting of QS whilst retarding that of CXA: the acceleration of C3S alone is sufficient to reduce the overall setting time of the composition relative to one without any accelerator.
Thus, the effect of mixing with the composition both an a-hydroxy-carbonyl compound and a water-soluble sodium or potassium carbonate compound is to moderate the effect of the former compound on C3A but not on C3S. Accordingly, the setting time of the composition is lengthened but the early strength development unaffected relative to a composition using the former compound alone.
Compounds possessing a plurality of hydroxyl groups moderate the effect of the two accelerators on both C3A and C3S, thereby delaying both setting and early strength development. The water-soluble polyhydroxy organic compounds appear to retard the setting of portland cement by coating the particles thereof with a film, thereby hindering access of water to the particles. However, the use of such organic compounds in the process and compositions of the invention still results in cement compositions which exhibit early strengths substantially greater than those obtained using prior art accelerators.
The following Examples are now given, though by way of illustration only, to show details of especially preferred processes and compositions of the invention.
Example I
The following dry mortars were prepared:
A B C
(parts by weight)
Atlas Type I Cement 78.0 77.8 77-.5
Federal Fine Sand 20.0 19.9 19.8
Sodium Hydroxyacetate 2.0 1.9 1.9
Sodium Carbonate 0.0 0.4 0.8
The final setting time of these mortars as measured by Vicat Needle test (using a water-cement weight ratio of 0.30 and carried out according to ASTM C 191) and the compressive strengths after one or five hours were as follows:
Setting time Compressive strength
Mortar A (control) 1'15" 1710 psi (5 hours)
Mortar B 3'30" 990 psi (1 hour)
Mortar C 17'30" 1080 psi (1 hour)
It is apparent that the addition of sodium carbonate lengthens the setting time of the mortar accelerated with sodium hydroxyacetate.
Example II
The following mortars were prepared:
D (control) E
(parts by weight)
Atlas Type I Cement 77.7 75.5
Federal Fine Sand 19.4 18.9
Sodium Lactate 2.9 2.8
Sodium Carbonate 0.0 2.8
The following final setting times were measured using the Vicat Needle test:
Setting Time Water-Cement Weight Ratio
Mortar D 1' 0.28
Mortar E 17' 0.29
Thus adding sodium carbonate to a mortar accelerated with sodium lactate is seen to increase the setting time significantly.
Example III
The following dry mortar was prepared:
Atlas Type I cement 600 g
Federal Fine Sand 400 g
Sodium Hydroxyacetate 5 g
From this mortar the following six samples were prepared for which the corresponding initial setting times were measured by the Gillmore Needle test (carried out in accordance with ASTM C 266)
Sodium Carbonate Sodium Gluconate Setting
Sample (weight percent) (weight percent) Time
F 0.2 0.0 3' 5"
G 0.5 0.0 4'10"
H 0.8 0.0 5'40"
I 0.2 0.02 17'15"
J 0.5 0.02 16'50"
K 0.8 0.02 3'30"
The weight percentages are relative to the total weight of the mortar sample. The water-cement weight ratio was 0.35.
Note that as the concentration of sodium carbonate increases from 0.2 to 0.5 weight percent. the setting time remains essentially constant for samples I and J, which include 0.02 weight percent of sodium gluconate. Over this concentration range, therefore, the setting time of the mortar is quite insensitive to the concentration of sodium carbonate.
Over the same concentration range the addition of sodium gluconate also has the effect of lengthening the initial setting time from about three or four minutes to about seventeen minutes. As the concentration of sodium carbonate is increased to 0.8 weight percent, the initial setting time drops to less than four minutes for the samples containing sodium gluconate. At this concentration, the usual accelerating effect of sodium carbonate apparently predominates over its retarding effect in combination with sodium hydroxyacetate.
Example IV
The following fast-setting, premixed mortar was prepared:
Parts by weight
Hercules Type I cement 79.270
Mason's Sand (ASTM C-144) 19.818
Sodium Hydroxyacetate 0.664
Sodium Carbonate 0.198
Sodium Gluconate 0.005
Stone Dust 0.045
The initial setting time of this mortar was between five and ten minutes as measured by the
Gillmore Needle test with a water-cement weight ratio of 0.3. This mortar is suitable as a quick-setting mortar compound.
WHAT WE CLAIM IS:
1. A process for accelerating the setting time of a predetermined quantity of a portland cement composition for a predetermined water-cement ratio by admixing with the composition an amount of a chemical admixture so as to produce an accelerated portland cement composition, said portland cement composition having for said predetermined water-cement ratio, in the absence of said admixture, a final setting time as measured by the
Vicat Needle test corresponding to a first control setting time, said chemical admixture containing::
(a.1) a first amount of an a-hydroxy carbonyl compound selected from the group consisting of hydroxyacetic acid, lactic acid, 2-methyllactic acid, dl-mandelic acid and thelr water-soluble salts, a control sample of the portland cement composition and the a-hydroxy carbonyl compound in proportions equivalent to the ratio of the predetermined quantity of the portland cement composition to the first amount of a-hydroxy carbonyl compound, having, at said predetermined water-cement ratio, a final setting time as measured by the
Vicat Needle test corresponding to a second control setting time, the first amount of a-hydroxy carbonyl compound being sufficient to accelerate the setting time of the predetermined quantity of portland cement composition so that the second control setting time is shorter than the first control setting time; and
(a.2) a second amount of water-soluble carbonate compound selected from the group consisting of sodium carbonate and potassium carbonate; and optionally
(a.3) a third amount of a water soluble organic retardant selected from the group consisting of retarding organic compounds having a plurality of hydroxy groups, citric acid, and the sodium, potassium and calcium salts of citric acid; said accelerated portland cement composition having, for said predetermined water-cement ratio, a final setting time measured by the Vicat Needle test corresponding to a test setting time, said amounts of the components of the chemical admixture being effective in combination to accelerate the setting time of the composition such that said test setting time is shorter than said first control setting time, the only constituents of the accelerated portland cement composition capable of appreciably affecting the setting time of a said portland cement composition being the carbonate compound, the a-hydroxy carbonyl compound, and said optional organic retardant, the portland cement, and, where present, water.
2. A process according to Claim 1 wherein the only constituents of the accelerated portland cement composition capable of affecting the setting time of a said portland cement composition are the carbonate compound, and the hydroxy carbonyl compound, and portland cement.
3 A process according to Claim 1 wherein the only constituents of the accelerated portland cement composition capable of affecting the setting time of said portland cement composition are the carbonate compound, the a-hydroxy carbonyl compound, portland cement, and water.
4. A process according to Claim 1 wherein the chemical admixture includes a third amount of a water-soluble organic retardant selected from the group consisting of retarding organic compounds having a plurality of hydroxy groups, citric acid, and the sodium, potassium, and calcium salts of citric acid; the first amount of a-hydroxy carbonyl compound, the second amount of carbonate compound, and the third amount of organic retardant being effective in combination to accelerate the portland cement composition
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (29)
1. A process for accelerating the setting time of a predetermined quantity of a portland cement composition for a predetermined water-cement ratio by admixing with the composition an amount of a chemical admixture so as to produce an accelerated portland cement composition, said portland cement composition having for said predetermined water-cement ratio, in the absence of said admixture, a final setting time as measured by the
Vicat Needle test corresponding to a first control setting time, said chemical admixture containing::
(a.1) a first amount of an a-hydroxy carbonyl compound selected from the group consisting of hydroxyacetic acid, lactic acid, 2-methyllactic acid, dl-mandelic acid and thelr water-soluble salts, a control sample of the portland cement composition and the a-hydroxy carbonyl compound in proportions equivalent to the ratio of the predetermined quantity of the portland cement composition to the first amount of a-hydroxy carbonyl compound, having, at said predetermined water-cement ratio, a final setting time as measured by the
Vicat Needle test corresponding to a second control setting time, the first amount of a-hydroxy carbonyl compound being sufficient to accelerate the setting time of the predetermined quantity of portland cement composition so that the second control setting time is shorter than the first control setting time; and
(a.2) a second amount of water-soluble carbonate compound selected from the group consisting of sodium carbonate and potassium carbonate; and optionally
(a.3) a third amount of a water soluble organic retardant selected from the group consisting of retarding organic compounds having a plurality of hydroxy groups, citric acid, and the sodium, potassium and calcium salts of citric acid; said accelerated portland cement composition having, for said predetermined water-cement ratio, a final setting time measured by the Vicat Needle test corresponding to a test setting time, said amounts of the components of the chemical admixture being effective in combination to accelerate the setting time of the composition such that said test setting time is shorter than said first control setting time, the only constituents of the accelerated portland cement composition capable of appreciably affecting the setting time of a said portland cement composition being the carbonate compound, the a-hydroxy carbonyl compound, and said optional organic retardant, the portland cement, and, where present, water.
2. A process according to Claim 1 wherein the only constituents of the accelerated portland cement composition capable of affecting the setting time of a said portland cement composition are the carbonate compound, and the hydroxy carbonyl compound, and portland cement.
3 A process according to Claim 1 wherein the only constituents of the accelerated portland cement composition capable of affecting the setting time of said portland cement composition are the carbonate compound, the a-hydroxy carbonyl compound, portland cement, and water.
4. A process according to Claim 1 wherein the chemical admixture includes a third amount of a water-soluble organic retardant selected from the group consisting of retarding organic compounds having a plurality of hydroxy groups, citric acid, and the sodium, potassium, and calcium salts of citric acid; the first amount of a-hydroxy carbonyl compound, the second amount of carbonate compound, and the third amount of organic retardant being effective in combination to accelerate the portland cement composition
such that said test setting time is shorter than the first control setting time.
5. A process according to Claim 4, wherein the only constituents of the accelerated portland cement composition capable of affecting the setting time of a said portland cement composition are the carbonate compound, the hydroxy carbonyl compound, the organic retardant, and portland cement.
6. A process according to Claim 4, wherein the only constituents of the. accelerated portland cement composition capable of affecting the setting time of a said portland cement composition are the carbonate compound, the a-hydroxy carbonyl compound, the organic retardant, portland cement, and water.
7. A process according to any one of Claims 1 to 6, wherein the test setting time is longer than the second control setting time.
8. A process according to any of Claims 1 to 7, wherein the carbonate compound is sodium carbonate and the a-hydroxyl carbonyl compound is sodium hydroxyacetate.
9. The process according to any one of Claims 4 to 8 wherein the organic retardant is sodium gluconate.
10. A process according to any one of Claims 4 to 7, in which:
(a) the carbonate compound is sodium carbonate, the ratio of the weight of the sodium carbonate to the weight of the cement being in the range of from 6 x 10-4 to 2 x 10-2; (b) the a-hydroxy carbonyl compound is sodium hydroxyacetate, the ratio of the weight of the sodium hydroxyacetate to the weight of the cement being in the range of from 6 x 10 to 5 x 102; and
(c) the organic retardant is sodium gluconate, the ratio of the weight of the sodium gluconate to the weight of the cement being in the range of from 8 x 10S to 3 x 10-2.
11. A fast-setting, premixed portland cement composition produced by a process according to any one of Claims 1 to 10, which consists essentially of:
(a) portland cement;
(b) aggregate;
(c) a first amount of an a-hydroxy carbonyl compound selected from the group consisting of dl-mandelic acid and the water-soluble salts of hydroxyacetic acid, lactic acid, 2-methyllactic acid, and dl-mandelic acid, the first amount being sufficient to accelerate the portland cement and aggregate mixture; and
(d) a second amount of water-soluble carbonate compound selected from the group consisting of sodium carbonate and potassium carbonate; and optionally
(e) a third amount of water-soluble organic retardant selected from the group consisting of retarding organic compounds having a plurality of hydroxy groups, citric acid, and the sodium potassium-, and calcium salts of citric acid; the first and the second amounts together with the optional third amount being effective in combination to accelerate the portland cement and aggregate mixture, essentially the only constituents of the accelerated portland cement composition capable of affecting the setting time of a said portland cement composition being the a-hydroxy carbonyl compound the carbonate compound and the portland cement, and said optional organic retardant.
12. A composition according to Claim 11 which composition contains said third amount of said water-soluble organic retardant.
13. A composition according to Claim 12 wherein the only constituents of the accelerated portland cement composition capable of affecting the setting time of a said portland cement composition are the a-hydroxy carbonyl compound, the carbonate compound, the organic retardant, and the portland cement.
14. A composition according to any one of Claims 11 to 13, wherein the first amount of the a-hydroxy carbonyl compound and the second amount of the water-soluble carbonate compound are such that the final setting time of the portland cement composition containing the first and second amounts is greater than the final setting time of a corresponding control portland cement composition in which the water-soluble carbonate compound is omitted, the final setting times being measured by the Vicat Needle test.
15. A composition according to any one of Claims 11 to 14 wherein the carbonate compound is sodium carbonate.
16. A composition according to any one of Claims 11 to 15 wherein the a-hydroxy carbonyl compound is sodium hydroxyacetate.
17. A composition according to any one of Claims 11 to 16, wherein the organic retardant is sodium gluconate.
18. A composition according to any one of Claims 11 to 17, wherein the a-hydroxy carbonyl compound is sodium hydroxyacetate, the ratio of the weight of the sodium hydroxyacetate to the weight of the cement being in the range of from 6 x 10-4 to 5 x 10-2; the carbonate compound is sodium carbonate, the ratio of the weight of the sodium carbonate to the weight of the cement being in the range of from 6 x 10-4 to 2 x 10-2, and the organic retardant is sodium gluconate. the ratio of the weight of the sodium gluconate to the weight of the cement being in the range of from 8 x 10-5 to 3 x 10-2.
19. A composition according to Claim 18, wherein the composition consists essentially of the following ingredients in approximately the proportions recited:
80 parts by weight of portland cement;
20 parts by weight of sand; 0.7 parts by weight of sodium hydroxyacetate;
0.2 parts by weight of sodium carbonate; and
0.005 parts by weight of sodium gluconate.
20. A composition of Claim 19 wherein the composition further includes approximately 0.05 parts by weight of stone dust.
21. An admixture for use in a process for accelerating the setting time of a portland cement composition according to any one of Claims 1 to 10 wherein the admixture consists essentially of a mixture of:
(a) a first amount of an a-hydroxy carbonyl compound selected from the group consisting the dl-mandelic acid and the water-soluble salts of hydroxyacetic acid, lactic acid, 2-methyllactic acid, and dl-mandelic acid;
(b) a second amount of a water-soluble carbonate compound selected from the group consisting of sodium carbonate and potassium carbonate; and
(c) a third amount of a water-soluble organic retardant selected from the group consisting of retarding organic compounds having a plurality of hydroxy groups, citric acid, and the sodium, potassium, and calcium salts of citric acid..
22. An admixture according to Claim 21 wherein the admixture consists of a mixture of the three components recited in Claim 21.
23. An admixture according to Claim 21 or Claim 22 wherein the water-soluble carbonate compound is sodium carbonate, and the a-hydroxy carbonyl compound is sodium hydroxyacetate.
24. An admixture according to Claim 23, wherein the organic retardant is sodium gluconate, and the weight ratio of the second amount of the first amount is in the range of from 0.01 to 33, and the weight of the third amount to the second amount is in the range of from 0.004 to 50.
25. A process for accelerating the setting time of a portland cement composition according to Claim 1 and substantially as herein described, with reference to any one of the
Examples.
26. The product of a process as claimed in any one of the Claims 1 to 10 and 25.
27. A product as claimed in Claim 26, when set.
28. A fast-setting premixed portland cement composition according to Claim 11 and substantially as herein described with particular reference to the Examples.
29. An admixture for use in a process for accelerating the setting time of a portland cement composition according to Claim 21 and substantially as herein described, with particular reference to the Examples.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US66308976A | 1976-03-02 | 1976-03-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1575450A true GB1575450A (en) | 1980-09-24 |
Family
ID=24660424
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7634/77A Expired GB1575450A (en) | 1976-03-02 | 1977-02-23 | Process and composition for accelerating the setting of portland cement compositions |
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| Country | Link |
|---|---|
| CA (1) | CA1078415A (en) |
| CH (1) | CH636327A5 (en) |
| DE (1) | DE2708808A1 (en) |
| GB (1) | GB1575450A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4746367A (en) * | 1986-12-17 | 1988-05-24 | The Dow Chemical Company | Superplasticizer composition for use with hydraulic cements |
| US5591259A (en) * | 1994-09-20 | 1997-01-07 | Sandoz Ltd. | Rapid setting cementitious compositions and method |
| US5629048A (en) * | 1994-09-20 | 1997-05-13 | Sandoz Ltd. | Rapid setting cementitious compositions and method |
| US5792252A (en) * | 1995-06-07 | 1998-08-11 | Mbt Holding Ag | Cement compositions and admixtures thereof |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6136183A (en) * | 1984-07-30 | 1986-02-20 | ミサワホ−ム株式会社 | Manufactre of foamed concrete |
| YU43948B (en) * | 1984-11-08 | 1989-12-31 | Centoedei Formzo Es Segedanyag | Protection method against water, for structure materials especially concrete and bricks |
| JPH0712963B2 (en) * | 1984-12-26 | 1995-02-15 | 電気化学工業株式会社 | Cement admixture for dam concrete and manufacturing method of dam concrete |
| DE4242107C1 (en) * | 1992-12-14 | 1994-06-01 | Heidelberger Zement Ag | Fast curing binder mixture and its use |
-
1977
- 1977-02-17 CA CA272,004A patent/CA1078415A/en not_active Expired
- 1977-02-23 GB GB7634/77A patent/GB1575450A/en not_active Expired
- 1977-03-01 DE DE19772708808 patent/DE2708808A1/en not_active Withdrawn
- 1977-03-01 CH CH257577A patent/CH636327A5/en not_active IP Right Cessation
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4746367A (en) * | 1986-12-17 | 1988-05-24 | The Dow Chemical Company | Superplasticizer composition for use with hydraulic cements |
| US5591259A (en) * | 1994-09-20 | 1997-01-07 | Sandoz Ltd. | Rapid setting cementitious compositions and method |
| US5629048A (en) * | 1994-09-20 | 1997-05-13 | Sandoz Ltd. | Rapid setting cementitious compositions and method |
| US5895525A (en) * | 1994-09-20 | 1999-04-20 | Mbt Holding Ag | Rapid setting cementitious compositions and method |
| US5792252A (en) * | 1995-06-07 | 1998-08-11 | Mbt Holding Ag | Cement compositions and admixtures thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CA1078415A (en) | 1980-05-27 |
| DE2708808A1 (en) | 1977-09-08 |
| CH636327A5 (en) | 1983-05-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930223 |