阅读说明：本技术 用于混凝土的早强剂 (Early strength agent for concrete ) 是由 葛梦婷 吕雪萍 蓝天 吕东城 班翠云 吴光文 莫仕新 于 2021-11-11 设计创作，主要内容包括：本发明公开了一种用于混凝土的早强剂,主要有以下原料制成：硫酸钙、纳米碳酸钙、改性纳米二氧化硅、三乙醇胺、硼酸、沸石粉、异丙醇和脂肪酸甲脂磺酸钠；所述改性纳米二氧化硅的制备方法如下：在催化剂条件下,将纳米二氧化硅、十二烷基苯磺酸钠、硅烷混合,在65-70℃条件下,转速为400-450r/min,反应0.5-1.5h。本发明用于混凝土的早强剂,各原料组份发挥协同互补作用,能快速的促进普通硅酸盐水泥早期强度,且后期强度不降低或小幅降低。同时还能抑制混凝土的泛霜效应。(The invention discloses an early strength agent for concrete, which is mainly prepared from the following raw materials: calcium sulfate, nano calcium carbonate, modified nano silicon dioxide, triethanolamine, boric acid, zeolite powder, isopropanol and sodium fatty acid methyl ester sulfonate; the preparation method of the modified nano silicon dioxide comprises the following steps: under the condition of a catalyst, mixing the nano silicon dioxide, the sodium dodecyl benzene sulfonate and the silane, and reacting for 0.5 to 1.5 hours at the rotating speed of 400-450r/min at the temperature of between 65 and 70 ℃. The early strength agent for concrete provided by the invention has the advantages that the raw material components play a synergistic and complementary role, the early strength of the ordinary portland cement can be rapidly promoted, and the later strength is not reduced or is slightly reduced. And simultaneously, the frosting effect of the concrete can be inhibited.)

1. An early strength agent for concrete is characterized by mainly comprising the following raw materials: calcium sulfate, nano calcium carbonate, modified nano silicon dioxide, triethanolamine, boric acid, zeolite powder, isopropanol and sodium fatty acid methyl ester sulfonate;

the preparation method of the modified nano silicon dioxide comprises the following steps: under the condition of a catalyst, mixing the nano silicon dioxide, the sodium dodecyl benzene sulfonate and the silane, and reacting for 0.5 to 1.5 hours at the rotating speed of 400-450r/min at the temperature of between 65 and 70 ℃.

2. The early strength agent for concrete according to claim 1, which is mainly prepared from the following raw materials in parts by weight: 20-35 parts of calcium sulfate, 15-20 parts of nano calcium carbonate, 8-18 parts of modified nano silicon dioxide, 5-10 parts of triethanolamine, 2-9 parts of boric acid, 5-10 parts of zeolite powder, 1-5 parts of isopropanol and 1-5 parts of sodium fatty acid methyl sulfonate.

3. The early strength agent for concrete according to claim 1, wherein the catalyst is nitric acid or hydrochloric acid.

4. The early strength agent for concrete according to claim 1, wherein the silane is methyltrimethoxysilane or hexadecyltrimethylsilane.

5. The early strength agent for concrete according to claim 1, wherein the mass ratio of the mixture of the nano-silica, the sodium dodecyl benzene sulfonate and the silane is 10-30:0.5-9: 1-10.

6. The early strength agent for concrete according to claim 1, further comprising: kaolin, calcium formate, sodium hydroxide, sodium nitrite, methacrylic acid and cellulose ether.

7. The early strength agent for concrete according to claim 6, further comprising, in parts by weight: 10-20 parts of kaolin, 5-15 parts of calcium formate, 1-3 parts of sodium hydroxide, 2-9 parts of sodium nitrite, 1-3 parts of methacrylic acid and 1-3 parts of cellulose ether.

8. The early strength agent for concrete according to claim 6, wherein the cellulose ether is one or more of hydroxyethyl methyl cellulose, carboxymethyl cellulose, ethyl cellulose, benzyl cellulose, hydroxyethyl cellulose and hydroxypropyl methyl cellulose.

9. Use of an early strength agent for concrete according to any one of claims 1 to 8, wherein the early strength agent is incorporated in an amount of 3 to 5% by mass of the cementitious material in the concrete.

Technical Field

The invention relates to the technical field of building materials, in particular to an early strength agent for concrete.

Background

The early strength agent is an additive which can improve the early strength of concrete and has no obvious influence on the later strength. The early strength agent has the main functions of accelerating the hydration speed of the cement and promoting the development of the early strength of the concrete. Not only has the early strength function, but also has certain water reducing and enhancing functions.

The concrete early strength agent is one of the earliest used additive varieties in the development history of the additive. Until now, various early strength type additives other than chloride and sulfate, such as nitrite, chromate, etc., have been developed; and organic early strength agents such as triethanolamine, calcium formate, urea, etc. And on the basis of the early strength agent, various compound additives such as an early strength water reducing agent, an early strength antifreezing agent, an early strength pumping agent and the like are produced and applied. Although the production and application history of the early strength agent is long, a great deal of work is needed in the aspect of the early strength agent along with deepening of the understanding degree of potential hazards of chloride ions, sulfate ions, nitrate ions, alkali metal ions and the like to the performance and the long-term stability of concrete and development of concrete with large mixing amount of slag powder or fly ash. The early strength agent is mainly used for increasing the reaction speed of cement and water, shortening the setting and hardening time of the cement and promoting the increase of the early strength of the concrete. The waterproof agent can improve the impermeability of concrete, reduce the mass water absorption rate of the concrete and obviously improve the durability.

The chloride early strength agent has obvious corrosion effect on the reinforcing steel bar, so the chloride early strength agent has little application. The application of the sulfate-series early strength agent is also greatly limited due to the fact that the sulfate-series early strength agent causes concrete to be frosted and has the risk of harming alkali aggregate reaction. Other kinds of early strength agents have the problems of poor early strength effect, influence on later strength, raw material source, difficulty in production cost and the like.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The invention aims to provide an early strength agent for concrete, so as to overcome the defects of concrete frosting, poor early strength effect and great reduction of later strength caused by the existing early strength agent.

In order to realize the purpose, the invention provides an early strength agent for concrete, which is mainly prepared from the following raw materials: calcium sulfate, nano calcium carbonate, modified nano silicon dioxide, triethanolamine, boric acid, zeolite powder, isopropanol and sodium fatty acid methyl ester sulfonate;

the preparation method of the modified nano silicon dioxide comprises the following steps: under the condition of a catalyst, mixing the nano silicon dioxide, the sodium dodecyl benzene sulfonate and the silane, and reacting for 0.5 to 1.5 hours at the rotating speed of 400-450r/min at the temperature of between 65 and 70 ℃.

Preferably, in the above technical scheme, the early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 20-35 parts of calcium sulfate, 15-20 parts of nano calcium carbonate, 8-18 parts of modified nano silicon dioxide, 5-10 parts of triethanolamine, 2-9 parts of boric acid, 5-10 parts of zeolite powder, 1-5 parts of isopropanol and 1-5 parts of sodium fatty acid methyl sulfonate.

Preferably, in the above technical scheme, the catalyst is nitric acid or hydrochloric acid.

Preferably, in the above technical scheme, the silane is methyltrimethoxysilane or hexadecyltrimethylsilane.

Preferably, in the technical scheme, the mass ratio of the nano silicon dioxide to the sodium dodecyl benzene sulfonate to the silane is 10-30:0.5-9: 1-10.

Preferably, in the above technical solution, the early strength agent for concrete further includes: kaolin, calcium formate, sodium hydroxide, sodium nitrite, methacrylic acid and cellulose ether.

Preferably, in the above technical solution, the early strength agent for concrete further includes, in parts by weight: 10-20 parts of kaolin, 5-15 parts of calcium formate, 1-3 parts of sodium hydroxide, 2-9 parts of sodium nitrite, 1-3 parts of methacrylic acid and 1-3 parts of cellulose ether.

Preferably, in the above technical solution, the cellulose ether is one or more of hydroxyethyl methyl cellulose, carboxymethyl cellulose, ethyl cellulose, benzyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose.

The early strength agent for the concrete is used, and the mixing amount of the early strength agent is 3-5% of the mass of the cementing material in the concrete.

Compared with the prior art, the invention has the following beneficial effects: the early strength agent for concrete provided by the invention has the advantages that the raw material components play a synergistic and complementary role, the early strength of the ordinary portland cement can be rapidly promoted, and the later strength is not reduced or is slightly reduced. And simultaneously, the frosting effect of the concrete can be inhibited.

Detailed Description

The following detailed description of the present invention will be given with reference to specific examples, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

Example 1

An early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 30 parts of calcium sulfate, 17 parts of nano calcium carbonate, 12 parts of modified nano silicon dioxide, 7 parts of triethanolamine, 5 parts of boric acid, 8 parts of zeolite powder, 3 parts of isopropanol, 3 parts of sodium fatty acid methyl ester sulfonate, 17 parts of kaolin, 9 parts of calcium formate, 2 parts of sodium hydroxide, 4 parts of sodium nitrite, 2 parts of methacrylic acid and 2 parts of hydroxyethyl methyl cellulose.

The preparation method of the modified nano silicon dioxide comprises the following steps: mixing the nano silicon dioxide, sodium dodecyl benzene sulfonate and methyltrimethoxysilane under the condition of nitric acid, and reacting for 1h at the rotating speed of 430r/min at the temperature of 65 ℃. The mass ratio of the nano silicon dioxide to the sodium dodecyl benzene sulfonate to the methyl trimethoxy silane is 25:3: 4.

When the concrete early strength admixture is used, the cementing material used by the concrete is ordinary portland cement, and the admixture amount of the early strength admixture is 4% of the mass of the ordinary portland cement.

Example 2

An early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 35 parts of calcium sulfate, 15 parts of nano calcium carbonate, 8 parts of modified nano silicon dioxide, 10 parts of triethanolamine, 2 parts of boric acid, 10 parts of zeolite powder, 1 part of isopropanol, 5 parts of sodium fatty acid methyl ester sulfonate, 20 parts of kaolin, 5 parts of calcium formate, 1 part of sodium hydroxide, 9 parts of sodium nitrite, 1 part of methacrylic acid and 1 part of carboxymethyl cellulose.

The preparation method of the modified nano silicon dioxide comprises the following steps: under the condition of hydrochloric acid, mixing the nano silicon dioxide, sodium dodecyl benzene sulfonate and hexadecyl trimethyl silane, and reacting for 1.5h at the temperature of 70 ℃ and the rotating speed of 450 r/min. The mass ratio of the nano silicon dioxide to the sodium dodecyl benzene sulfonate to the hexadecyl trimethyl silane is 30:2: 1.

When the concrete early strength admixture is used, the cementing material used by the concrete is ordinary portland cement, and the admixture amount of the early strength admixture is 3% of the mass of the ordinary portland cement.

Example 3

An early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 20 parts of calcium sulfate, 20 parts of nano calcium carbonate, 18 parts of modified nano silicon dioxide, 5 parts of triethanolamine, 9 parts of boric acid, 5 parts of zeolite powder, 5 parts of isopropanol, 1 part of sodium fatty acid methyl ester sulfonate, 10 parts of kaolin, 15 parts of calcium formate, 3 parts of sodium hydroxide, 2 parts of sodium nitrite, 3 parts of methacrylic acid and 3 parts of ethyl cellulose.

The preparation method of the modified nano silicon dioxide comprises the following steps: mixing the nano silicon dioxide, sodium dodecyl benzene sulfonate and methyl trimethoxy silane under the condition of nitric acid, and reacting for 0.5h at the rotating speed of 450r/min at the temperature of 65 ℃. The mass ratio of the nano silicon dioxide to the sodium dodecyl benzene sulfonate to the methyl trimethoxy silane is 10:0.5: 2.

When the concrete early strength admixture is used, the cementing material used by the concrete is ordinary portland cement, and the admixture amount of the early strength admixture is 3.3% of the mass of the ordinary portland cement.

Example 4

An early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 32 parts of calcium sulfate, 18 parts of nano calcium carbonate, 8 parts of modified nano silicon dioxide, 10 parts of triethanolamine, 3 parts of boric acid, 7 parts of zeolite powder, 3 parts of isopropanol, 1 part of sodium fatty acid methyl ester sulfonate, 13 parts of kaolin, 6 parts of calcium formate, 3 parts of sodium hydroxide, 6 parts of sodium nitrite, 1 part of methacrylic acid and 2 parts of ethyl cellulose.

The preparation method of the modified nano silicon dioxide comprises the following steps: under the condition of nitric acid, mixing the nano silicon dioxide, sodium dodecyl benzene sulfonate and hexadecyl trimethyl silane, and reacting for 0.5-1.5h at the rotating speed of 400-450r/min at the temperature of 65-70 ℃. The mass ratio of the nano silicon dioxide to the sodium dodecyl benzene sulfonate to the hexadecyl trimethyl silane is 20: 4: 3.

when in use, the cementing material used by the concrete is ordinary portland cement, and the mixing amount of the early strength agent is 4.2 percent of the mass of the ordinary portland cement.

Example 5

An early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 26 parts of calcium sulfate, 16 parts of nano calcium carbonate, 11 parts of modified nano silicon dioxide, 6 parts of triethanolamine, 4 parts of boric acid, 7 parts of zeolite powder, 1 part of isopropanol, 5 parts of fatty acid methyl ester sodium sulfonate, 13 parts of kaolin, 12 parts of calcium formate, 2 parts of sodium hydroxide, 6 parts of sodium nitrite, 2 parts of methacrylic acid and 1 part of hydroxyethyl cellulose.

The preparation method of the modified nano silicon dioxide comprises the following steps: under the condition of hydrochloric acid, mixing the nano silicon dioxide, sodium dodecyl benzene sulfonate and hexadecyl trimethyl silane, and reacting for 0.5-1.5h at the temperature of 65-70 ℃ and the rotating speed of 400-450 r/min. The mass ratio of the nano silicon dioxide to the sodium dodecyl benzene sulfonate to the silane is 16:3: 7.

When the concrete early strength admixture is used, the cementing material used by the concrete is ordinary portland cement, and the admixture amount of the early strength admixture is 5% of the mass of the ordinary portland cement.

Example 6

An early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 30 parts of calcium sulfate, 15 parts of nano calcium carbonate, 18 parts of modified nano silicon dioxide, 7 parts of triethanolamine, 3 parts of boric acid, 9 parts of zeolite powder, 5 parts of isopropanol, 1 part of sodium fatty acid methyl ester sulfonate, 13 parts of kaolin, 7 parts of calcium formate, 1 part of sodium hydroxide, 4 parts of sodium nitrite, 2 parts of methacrylic acid and 3 parts of hydroxyethyl methyl cellulose.

The preparation method of the modified nano silicon dioxide comprises the following steps: mixing nano silicon dioxide, sodium dodecyl benzene sulfonate and methyltrimethoxysilane under the condition of hydrochloric acid, and reacting for 1h at the rotating speed of 430r/min at the temperature of 65 ℃. The mass ratio of the nano silicon dioxide to the sodium dodecyl benzene sulfonate to the methyl trimethoxy silane is 24:5: 2.

When the concrete early strength admixture is used, the cementing material used by the concrete is ordinary portland cement, and the admixture amount of the early strength admixture is 3.6 percent of the mass of the ordinary portland cement.

Comparative example 1

An early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 30 parts of calcium sulfate, 17 parts of nano calcium carbonate, 7 parts of triethanolamine, 5 parts of boric acid, 8 parts of zeolite powder, 3 parts of isopropanol, 3 parts of sodium fatty acid methyl sulfonate, 17 parts of kaolin, 9 parts of calcium formate, 2 parts of sodium hydroxide, 4 parts of sodium nitrite, 2 parts of methacrylic acid and 2 parts of hydroxyethyl methyl cellulose.

When the concrete early strength admixture is used, the cementing material used by the concrete is ordinary portland cement, and the admixture amount of the early strength admixture is 4% of the mass of the ordinary portland cement.

Comparative example 2

An early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 30 parts of calcium sulfate, 17 parts of nano calcium carbonate, 7 parts of triethanolamine, 3 parts of isopropanol, 3 parts of fatty acid methyl ester sodium sulfonate, 9 parts of calcium formate, 2 parts of sodium hydroxide, 4 parts of sodium nitrite, 2 parts of methacrylic acid and 2 parts of hydroxyethyl methyl cellulose.

When the concrete early strength admixture is used, the cementing material used by the concrete is ordinary portland cement, and the admixture amount of the early strength admixture is 4% of the mass of the ordinary portland cement.

Comparative example 3

An early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 30 parts of calcium sulfate, 17 parts of nano calcium carbonate, 12 parts of modified nano silicon dioxide, 7 parts of triethanolamine, 3 parts of isopropanol, 3 parts of sodium fatty acid methyl sulfonate, 9 parts of calcium formate, 2 parts of sodium hydroxide, 2 parts of methacrylic acid and 2 parts of hydroxyethyl methyl cellulose.

The preparation method of the modified nano silicon dioxide comprises the following steps: mixing the nano silicon dioxide, sodium dodecyl benzene sulfonate and methyltrimethoxysilane under the condition of nitric acid, and reacting for 1h at the rotating speed of 430r/min at the temperature of 65 ℃. The mass ratio of the nano silicon dioxide to the sodium dodecyl benzene sulfonate to the methyl trimethoxy silane is 25:3: 4.

When the concrete early strength admixture is used, the cementing material used by the concrete is ordinary portland cement, and the admixture amount of the early strength admixture is 4% of the mass of the ordinary portland cement.

Comparative example 4

An early strength agent for concrete is mainly prepared from the following raw materials in parts by weight: 30 parts of calcium sulfate, 17 parts of nano calcium carbonate, 12 parts of nano silicon dioxide, 7 parts of triethanolamine, 5 parts of boric acid, 8 parts of zeolite powder, 3 parts of isopropanol, 3 parts of sodium fatty acid methyl ester sulfonate, 17 parts of kaolin, 9 parts of calcium formate, 2 parts of sodium hydroxide, 4 parts of sodium nitrite, 2 parts of methacrylic acid and 2 parts of hydroxyethyl methyl cellulose.

When the concrete early strength admixture is used, the cementing material used by the concrete is ordinary portland cement, and the admixture amount of the early strength admixture is 4% of the mass of the ordinary portland cement.

The early strength agents of examples 1 to 6 and comparative examples 1 to 4 were used for concrete, and the formulation of the concrete is shown in table 1.

TABLE 1 concrete ratio (kg/m)³)

Cement	Fly ash	Mineral powder	Sand	Stone	Water (W)
						360	76	115	730	990	153

And curing the obtained ordinary portland cement mixture under standard curing conditions, detecting the compressive strength of concrete l, 3 and 7d, the compressive strength of concrete 28d and the mass water absorption rate of the ordinary portland cement mixture in the age of 28d according to the test specification GB/T50081-2002 of the ordinary concrete mechanical property test standard, and taking the concrete without the early strength agent as a blank group. The data obtained in the above examples and comparative examples are shown in the data in table 2.

TABLE 2

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.