CEMENT COMPOSITION ADDITIVE CONTAINING POLYCARBOXYLIC ACID COPOLYMER, ZINC OXIDE PARTICLES AND GLUCONATE

Abstract

Disclosed are a cement composition additive with improved compressive strength and workability, including a polycarboxylic acid copolymer and/or a salt thereof, zinc oxide particles, and a predetermined amount of gluconic acid and/or a salt thereof, and a cement composition containing the same.

Claims

1. A cement composition additive comprising: a polycarboxylic acid copolymer and/or a salt thereof; zinc oxide; and gluconic acid and/or a salt thereof.

2. The cement composition additive according to claim 1, wherein, when the cement composition additive comprises a salt of a polycarboxylic acid copolymer, the salt of the polycarboxylic acid copolymer is obtained by neutralizing the polycarboxylic acid copolymer with an alkaline substance.

3. The cement composition additive according to claim 2, wherein the alkaline substance comprises one or more selected from the group consisting of hydroxides, chlorides, carbonates, ammonia and organic amines of a metal having an oxidation number of +1 or +2.

4. The cement composition additive according to claim 1, wherein, when the cement composition additive comprises a salt of gluconic acid, the salt of gluconic acid is sodium gluconate or potassium gluconate.

5. The cement composition additive according to claim 4, wherein the salt of gluconic acid is sodium gluconate.

6. The cement composition additive according to claim 1, wherein the polycarboxylic acid copolymer is a copolymer of a monomer mixture comprising an alkoxypolyalkylene glycol mono(meth)acrylic acid ester monomer and a (meth)acrylic acid monomer.

7. The cement composition additive according to claim 6, wherein the polycarboxylic acid copolymer is a copolymer of a monomer mixture comprising 60% by weight to 99% by weight of an alkoxypolyalkylene glycol mono(meth)acrylic acid ester monomer and 1% by weight to 40% by weight of an (meth)acrylic acid monomer, based on the total weight of the copolymer.

8. The cement composition additive according to claim 6, wherein the monomer mixture further comprises polyoxyalkylene alkenyl ether sulfate.

9. The cement composition additive according to claim 1, wherein the polycarboxylic acid copolymer has a weight average molecular weight of 30,000 to 70,000.

10. A cement composition comprising the cement composition additive according to claim 1, wherein the cement composition comprises: a polycarboxylic acid copolymer and/or a salt thereof; zinc oxide particles; gluconic acid and/or a salt thereof; and cement.

11. The cement composition according to claim 10, wherein the polycarboxylic acid copolymer is present in an amount of 0.05 parts by weight to 1 part by weight, with respect to 100 parts by weight of the cement.

12. The cement composition according to claim 10, wherein the gluconic acid and/or a salt thereof is present in an amount of 1 part by weight to 7 parts by weight with respect to 100 parts by weight of the cement.

13. The cement composition according to claim 12, wherein the gluconic acid and/or a salt thereof is present in an amount of 2 part by weight to 6 parts by weight, with respect to 100 parts by weight of the cement.

14. The cement composition according to claim 10, wherein the cement is Portland cement.

15. The cement composition according to claim 14, wherein the Portland cement is made of one or more selected from the group consisting of limestone, clay, ganister, marble and pyrite.

16. The cement composition according to claim 14, wherein the Portland cement comprises one or more selected from the group consisting of ordinary Portland cement, moderate heat Portland cement, high initial strength Portland cement, low heat Portland cement, high sulfate resistant Portland cement and white Portland cement.

17. A mortar composition comprising the cement composition according to claim 10, sand and water.

18. A method of preventing deterioration in flowability of the cement composition according to claim 17, the method comprising: supplying an additive including: a polycarboxylic acid copolymer and/or a salt of the copolymer obtained by neutralizing the copolymer with an alkaline substance; zinc oxide particles; and gluconate to prepare a cement composition; and continuously entraining air to the cement composition.

19. A concrete composition comprising the cement composition according to claim 10, sand, rubble and water.

Description

BEST MODE

[0049] Now, the present invention will be described in more detail with reference to the following examples. These examples are provided only to illustrate the present invention and should not be construed as limiting the scope and spirit of the present invention.

[0050] In addition, in the following Example, ingredients constituting the cement composition are designated by trade names of certain manufacturers and detailed information associated therewith can be obtained from the respective products.

Example 1

[0051] A cement composition including 0.2 parts by weight of a water-soluble polycarboxylic acid copolymer (LG Chem. Ltd., under the trade name of CP-WRM50), 3 parts by weight of zinc oxide nano-particles, and 2 parts by weight of sodium gluconate, with respect to 100 parts by weight of cement was prepared.

Example 2

[0052] A cement composition was prepared in the same manner as Example 1, except that the amount of the sodium gluconate added was 4 parts by weight, with respect to 100 parts by weight of the cement.

Example 3

[0053] A cement composition was prepared in the same manner as Example 1, except that the amount of the sodium gluconate added was 6 parts by weight, with respect to 100 parts by weight of the cement.

Comparative Example 1

[0054] A cement composition was prepared in the same manner as Example 1, except that sodium gluconate was not added.

Comparative Example 2

[0055] A cement composition was prepared in the same manner as Example 1, except that zinc oxide nano-particles were not added and the amount of sodium gluconate added was 4 parts by weight, with respect to 100 parts by weight of the cement.

Reference Example 1

[0056] A cement composition was prepared in the same manner as Example 1, except that the amount of sodium gluconate added was 8 parts by weight, with respect to 100 parts by weight of the cement.

[0057] The main ingredients of cement compositions prepared in Examples,

[0058] Comparative Examples and Reference Example are shown in Table 1 below.

TABLE-US-00001 TABLE 1 Amount of CP- Amount of sodium WRM50 Amount of ZnO.sub.2 gluconate Added Added Added Item (parts by weight) (parts by weight) (parts by weight) Example 1 0.2 3 2 Example 2 4 Example 3 6 Comparative 0.2 3 0 Example 1 Comparative 0 4 Example 2 Reference 0.2 3 8 Example 1

Test Example 1

Mortar Flowability Test

[0059] 665 g of ordinary Portland cement (produced by Ssangyong Cement Industrial Co., Ltd.), 1,350 g of sand (standard sand), 332.5 g of water (service water) and each of the cement compositions prepared in Examples, Comparative Examples and Reference Example were kneaded at a medium rate in a mortar mixer for 3 minutes to prepare mortars.

[0060] The respective prepared mortars were charged in empty cones having a diameter of 60 mm and a height of 40 mm and the cones were removed vertically. A mortar flow value (mm) was defined as an average of mortar diameter values measured in two directions and a length decreased in a vertical direction was measured. Results are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Mortar Mortar flow value flow value Concrete Concrete Items (mm) (mm) slump (mm) slump (mm) — Initial stage After 30 min Initial stage After 30 min Example 1 160 142 215 190 Example 2 162 151 215 195 Example 3 163 152 220 205 Comparative 159 127 215 140 Example 1 Comparative 161 150 215 200 Example 2 Reference 162 158 220 210 Example 1

[0061] As can be seen from Table 2, Examples 1 to 3 and Reference Example 1 including zinc oxide particles and sodium gluconate exhibit similar sodium mortar flow value and concrete slump in an initial stage to Comparative Example 1 not including sodium gluconate, while a significant difference in mortar flow value and concrete slump after 30 min therebetween is observed.

[0062] That is, as compared to Examples 1 to 3 and Reference Example 1 including sodium gluconate, Comparative Example 1 not including sodium gluconate exhibits remarkably deteriorated workability because cement or concrete hardens before handled due to excessively high curing rate.

[0063] Meanwhile, Comparative Example 2 including only sodium gluconate with a polycarboxylic acid copolymer exhibits similar flowability and slump values and thus superior workability to Examples and Reference Example, but have problems of excessively thin concrete paste and severe separation of ingredients.

[0064] That is, when sodium gluconate is added, it prevents zinc oxide nano-particles from being rapidly cured, thereby maintaining excellent workability.

Test Example 2

Concrete Test

[0065] 3.53 kg of ordinary Portland cement (produced by Ssangyong Cement Industrial Co., Ltd.), 7.94 kg of sand (standard sand), 10.01 kg of rubble, 1.66 kg of water (service water) and each of the cement compositions prepared in Examples, Comparative Examples and Reference Example were kneaded to prepare concretes.

[0066] The slump, amount of air and compressive strength of respective prepared concretes were measured in accordance with Korean Industrial Standards KSF 2402 and KSF 2449.

TABLE-US-00003 TABLE 3 Amount Com- Amount of of pressive Compressive Compressive air (%) air (%) strength strength strength Item Initial After (MPa) (MPa) (MPa) — stage 30 min 3 days 7 days 28 days Example 1 3.4 3.0 15 20 34 Example 2 3.5 3.1 18 25 40 Example 3 3.7 3.0 17 24 38 Comparative 3.5 2.7 16 21 35 Example 1 Comparative 4.8 4.6 16 22 37 Example 2 Reference 4.9 4.4 12 18 31 Example 1

[0067] Examples 1 to 3 and Comparative Example 1 are similar in terms of the amount of air and compressive strength of concrete shown in Table 3 and Example 2 exhibits high compressive strength over time. This is considered to be due to effects of sodium gluconate on hydration delay and mutual effects of zinc oxide particles.

[0068] On the other hand, Comparative Example 2 not including zinc oxide particles exhibits similar workability to Test Example 1, but disadvantageously has excessively high amount of air.

[0069] Meanwhile, Reference Example 1 exhibits improved workability due to addition of zinc oxide particles and a slightly great amount of sodium gluconate, but exhibits high amount of air and low compressive strength. That is, when the amount of sodium gluconate added exceeds 6 parts by weight, with respect to 100 parts by weight of the cement, curing of specimens is delayed due to hydration delay of sodium gluconate, control of concrete mixing is difficult and compressive strength is lowered.

[0070] Accordingly, sodium gluconate is preferably added in an amount not causing deterioration in compressive strength and an optimal content of sodium gluconate facilitating workability is preferably 1 part by weight to 7 parts by weight, specifically 2 parts by weight to 6 parts by weight, most preferably, 4 parts by weight, with respect to 100 parts by weight of the cement, as shown in Example 2.

[0071] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

INDUSTRIAL APPLICABILITY

[0072] As apparent from the fore-going, the present invention can increase flowability of the composition and thereby obtain enhanced workability and high compressive strength, and can potently prevent deterioration of the cement composition over time even in high water reduction areas of particles by using a cement composition additive prepared by incorporating zinc oxide particles, and gluconic acid and/or a salt thereof in a polycarboxylic acid copolymer and/or a salt thereof.