阅读说明：本技术 一种混凝土防碳化抑制剂及其制备方法 (Concrete anti-carbonization inhibitor and preparation method thereof ) 是由 张欣 文家新 王婧 冒朝静 于 2021-08-17 设计创作，主要内容包括：本发明公开了一种混凝土防碳化抑制剂及其制备方法,涉及混凝土表面防护技术领域。所述防碳化抑制剂包括成膜剂、成膜促进剂、CO-(2)吸收剂、封孔剂和渗透剂；其中成膜剂是氟硅酸镁、氟硅酸钠和γ-(2,3-环氧丙氧)丙基三甲氧基硅烷中的一种或几种；成膜促进剂是硅酸锂、硅酸钠及硅酸钾中的一种或几种；CO-(2)吸收剂为碳酸钾、碳酸钠、三乙醇胺和2,2-二羟基二乙胺中的一种或几种；封孔剂为改性硅溶胶；渗透剂为十六烷基三甲基溴化铵、十六醇聚氧乙烯醚二甲基辛烷基氯化铵和十八烷基二甲基苄基氯化铵中的一种或几种。本发明所述的混凝土防碳化抑制剂原料易得、制备工艺简单,既可以将CO-(2)物理隔离,又可以吸收扩散至混凝土表面的CO-(2),实现了混凝土碳化抑制双重保护。(The invention discloses a concrete anti-carbonization inhibitor and a preparation method thereof, and relates to the technical field of concrete surface protection. The anti-carbonization inhibitor comprises a film forming agent, a film forming promoter and CO 2 Absorbents, hole sealing agents, and penetrants; wherein the film-forming agent is one or more of magnesium fluosilicate, sodium fluosilicate and gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane; the film forming promoter is one or more of lithium silicate, sodium silicate and potassium silicate; CO 2 2 The absorbent is one or more of potassium carbonate, sodium carbonate, triethanolamine and 2, 2-dihydroxyl diethylamine; the hole sealing agent is modified silica sol; the penetrating agent is one or more of cetyl trimethyl ammonium bromide, cetyl polyoxyethylene ether dimethyl octane ammonium chloride and octadecyl dimethyl benzyl ammonium chloride. The concrete anti-carbonization inhibitor has easily obtained raw materials and simple preparation process, and can be used for not only adding CO 2 Physically isolating and absorbing CO diffused to the surface of concrete 2 And double protection of concrete carbonization inhibition is realized.)

1. The concrete anti-carbonization inhibitor is characterized by comprising the following components: film forming agent, film forming promoter, CO₂Absorbents, hole sealing agents, and penetrants;

wherein the film-forming agent is one or more of magnesium fluosilicate, sodium fluosilicate and gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane; the film forming promoter is one or more of lithium silicate, sodium silicate and potassium silicate; CO 2₂The absorbent is one or more of potassium carbonate, sodium carbonate, triethanolamine and 2, 2-dihydroxyl diethylamine; the hole sealing agent is modified silica sol; the penetrating agent is one or more of cetyl trimethyl ammonium bromide, cetyl polyoxyethylene ether dimethyl octane ammonium chloride and octadecyl dimethyl benzyl ammonium chloride.

2. The concrete anti-carbonation inhibitor according to claim 1, wherein said CO is selected from the group consisting of₂The absorbent comprises two types of inorganic absorbent and organic absorbent, the total mass concentration of the inorganic absorbent and the organic absorbent is 7-15%, and the inorganic absorbent and the organic absorbent are inorganic CO and organic CO₂The mass ratio of the absorbent is 1: 3-1: 1.

3. The concrete anti-carbonization inhibitor as claimed in claim 1, wherein the mass ratio of the film-forming agent to the film-forming accelerator is 1:1 to 3: 1.

4. The concrete anti-carbonization inhibitor as claimed in claim 1, wherein the mass concentration of the penetrant is 0.2-1%.

5. The preparation method of the concrete anti-carbonization inhibitor is characterized by comprising the following specific steps:

s1, slowly adding 100mL of sodium metaaluminate solution with a certain concentration into 250g of acidic silica sol to obtain a mixed solution, carrying out reflux reaction on the mixed solution at a certain temperature for a certain time, and after the reaction solution is cooled to room temperature, adjusting the pH value of the reaction solution to 3.0 by using 1mol/L hydrochloric acid solution to obtain a modified silica sol solution hole sealing agent;

s2. theFilm forming agent, film forming promoter and inorganic CO₂Adding an absorbent into deionized water, heating and stirring at a certain temperature until a colorless and transparent solution A is obtained;

s3, organic CO is added₂Adding an absorbent into a small amount of absolute ethyl alcohol to prepare a colorless transparent solution B;

s4, adding the hole sealing agent solution prepared by the solution B, S1 prepared by the S3 and a small amount of penetrating agent into the solution A prepared by the S2, adding water to dilute to a certain volume, and stirring until the hole sealing agent solution and the small amount of penetrating agent are completely dissolved to obtain the milky anti-carbonization inhibitor.

6. The method for preparing the concrete anti-carbonization inhibitor according to claim 5, wherein: the concentration of the sodium metaaluminate solution in the S1 is 2-10%, the heating temperature of the reaction is 100-150 ℃, and the heating time is 50-100 min.

7. The method for preparing the concrete anti-carbonization inhibitor according to claim 5, wherein: the heating temperature in the S2 is 35-70 ℃.

Technical Field

The invention relates to the technical field of novel building materials, in particular to a concrete anti-carbonization inhibitor and a preparation method thereof.

Background

The formation of concrete is mainly due to cementThe chemical reaction with water, and the hydration reaction between the two can generate higher strength hydrate in the substance. The basic materials such as stones, sand and admixture are added, so that the sand and stones in a dispersed state can be coagulated and bonded into a pile by virtue of hydrate with higher strength, and the concrete required by construction engineering is formed. The carbonization of concrete is caused by chemical action of hydrate formed by reaction of cement and water when contacting carbon dioxide in the air, and is also called as a neutralization process of concrete. Generally, the mineral content in cement is more than tricalcium silicate and dicalcium silicate, which account for about 75% of the total weight, the hydrated calcium silicate gel produced after the cement is completely hydrated accounts for about 50% of the total volume, the calcium hydroxide accounts for about 25%, the strength of the set cement mainly depends on the hydrated calcium silicate, and the content of the set cement in concrete accounts for 25% of the total volume. CO permeating into inner pores of concrete₂The calcium carbonate and the like interact with hydrated calcium silicate, calcium hydroxide and the like generated in the hydration process of the cement to generate products such as calcium carbonate and the like until the pH value of the pore liquid in the concrete is reduced to 8.5-9.0. The main chemical reactions of the concrete carbonization process can be expressed as:

CO₂+H₂O→H₂CO₃

Ca(OH)₂+H₂CO₃→CaCO₃+2H₂O

2CaCO·2SiO₂·3H₂O+3H₂CO₃→CaCO₃+2SiO₂+6H₂O

2CaCO·2SiO₂·4H₂O+2H₂CO₃→2CaCO₃+2SiO₂+6H₂O

the carbonization of concrete is a very complex multiphase physical and chemical continuous process in gas phase, liquid phase and solid phase of concrete, which can lead to the continuous consumption of alkaline substances in the concrete and the reduction of the alkalinity of the concrete, which can increase the number of hydrogen ions in a concrete pore solution, and lead to the weakening of the protective effect of the concrete on reinforcing steel bars. When the carbonization depth exceeds the thickness of the concrete protective layer, under the condition of the existence of water and air, the concrete loses the protective effect on the reinforcing steel bars, so that the reinforcing steel bars begin to corrode, and the strength and the comprehensive performance of the reinforced concrete structure are gradually reduced.

Concrete carbonation has the saying that concrete "cancer" must be effectively inhibited. In recent years, concrete carbonization inhibition methods mainly include concrete proportioning optimization, development of carbonization-resistant cement and additives, improvement of concrete curing measures and the like, but the methods also generally have the problems of poor carbonization inhibition effect, high cost, complex implementation procedure and the like. Therefore, in order to solve the problem of concrete carbonization, it is necessary to develop a novel concrete carbonization inhibitor and a preparation method thereof.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a novel concrete anti-carbonization inhibitor and a preparation method thereof, which solve the problems that the alkalinity of concrete is reduced after the concrete is carbonized, the protective effect of the concrete on reinforcing steel bars is weakened, and the overall strength and the comprehensive performance of a reinforced concrete structure are reduced, and improve the durability of the reinforced concrete structure.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme: a concrete anti-carbonization inhibitor comprises the following components: film forming agent, film forming promoter, CO₂Absorbents, hole sealing agents, and penetrants;

wherein the film-forming agent is one or more of magnesium fluosilicate, sodium fluosilicate and gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane; the film forming promoter is one or more of lithium silicate, sodium silicate and potassium silicate; CO 2₂The absorbent is one or more of potassium carbonate, sodium carbonate, triethanolamine and 2, 2-dihydroxyl diethylamine; the hole sealing agent is modified silica sol; the penetrating agent is one or more of cetyl trimethyl ammonium bromide, cetyl polyoxyethylene ether dimethyl octane ammonium chloride and octadecyl dimethyl benzyl ammonium chloride. Under the action of the film forming promoter, the film forming agent can form a hydrophobic film on the surface of the concrete and mix the surface of the concrete with CO₂Isolating; the hole sealing agent can seal holes or defects of the anti-carbonization film; CO 2₂The absorbent can absorb CO diffused to the surface of concrete₂A gas; the penetrant can promote the film-forming agent to permeate into the concrete, react with the concrete cementing material to form a structure similar to enamel, improve the compactness of the internal concrete and prevent CO₂And permeating into the concrete.

Preferably, the CO is₂The absorbent comprises two types of inorganic absorbent and organic absorbent, the total mass concentration of the inorganic absorbent and the organic absorbent is 7-15%, and the inorganic absorbent and the organic absorbent are inorganic CO and organic CO₂The mass ratio of the absorbent is 1: 3-1: 1.

Preferably, the mass ratio of the film forming agent to the film forming accelerant is 1: 1-3: 1.

Preferably, the mass concentration of the penetrating agent is 0.2-1%.

A preparation method of a concrete anti-carbonization inhibitor comprises the following specific steps:

s1, slowly adding 100mL of sodium metaaluminate solution with a certain concentration into 250g of acidic silica sol to obtain a mixed solution, carrying out reflux reaction on the mixed solution at a certain temperature for a certain time, and after the reaction solution is cooled to room temperature, adjusting the pH value of the reaction solution to 3.0 by using 1mol/L hydrochloric acid solution to obtain a modified silica sol hole sealing agent;

s2, adding a film forming agent, a film forming promoter and inorganic CO₂Adding an absorbent into deionized water, heating and stirring at a certain temperature until a colorless and transparent solution A is obtained;

s3, organic CO is added₂Adding an absorbent into absolute ethyl alcohol to prepare a colorless transparent solution B;

s4, adding the hole sealing agent solution prepared from the solution B, S1 prepared from the S3 and a small amount of penetrating agent into the solution A prepared from the S2, adding water to dilute to a certain volume, and stirring until the hole sealing agent solution and the small amount of penetrating agent are completely dissolved to obtain the milky anti-carbonization inhibitor.

Preferably, the concentration of the sodium metaaluminate solution in the S1 is 2-10%, the heating temperature of the reaction is 100-150 ℃, and the heating time is 50-100 min.

Preferably, the heating temperature in S2 is 35 to 70 ℃.

Concrete carbonation and CO₂The concentration, the concrete surface water content and the like of the inhibitor have close relations, and the anti-carbonization inhibitor prepared by the invention has the functions of chemical absorption and physical isolation of CO₂The function of (c). On one hand, the anti-carbonization protective agent provided by the invention can form a film on the surface of concrete, and the film can chemically absorb CO diffused to the surface of the concrete₂Chemical absorption of CO₂The mechanism of (2) is as follows:

K₂CO₃→2K++CO₃ ²+

R₂NH+CO₂→R₂NCOOH

R₂NCOOH→R₂NCOO-H+H+

R₂NCOO-+H₂O→R₂NH+HCO₃-

H++CO₃ ²-→HCO₃-

K++HCHO₃ ²-→KHCO₃

wherein R is HOCHO₂CH₂—。

The equilibrium concentration (partial pressure) of carbon dioxide in the membrane layer can be calculated by the following formula:

on the other hand, carbon dioxide permeates into the concrete through the gap defects such as pores, bubbles, cracks, capillaries and the like existing on the surface of the concrete, so that the concrete is carbonized; the anti-carbonization inhibitor provided by the invention can not only form a hydrophobic film layer on the surface of concrete, but also permeate into the concrete to react with a cementing material in the concrete, thereby improving the compactness of the concrete and effectively preventing CO₂The concrete is diffused into the concrete, and the function of physical isolation is exerted.

(III) advantageous effects

The invention provides a concrete anti-carbonization inhibitor and a preparation method thereof. The method has the following beneficial effects:

1. the concrete anti-carbonization inhibitor and the preparation method thereof have wide raw material sources and simple preparation process, and can not only convert CO into CO₂Physically isolated from the concrete surface and capable of absorbing CO diffused to the concrete surface₂And double protection of concrete against carbonization is realized.

2. The average carbonization depth of the concrete surface treated by the concrete carbonization inhibitor provided by the invention is only 0.13mm after the curing period is finished, is obviously 2.32mm lower than the average carbonization depth of the untreated concrete surface, and has obvious carbonization inhibition effect.

Drawings

FIG. 1 is a flow chart of the production process of the carbonation inhibitor of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The first embodiment is as follows:

as shown in fig. 1, firstly, slowly adding 100mL of 2% sodium metaaluminate solution into 250g of acidic silica sol to obtain a mixed solution, then carrying out reflux reaction on the mixed solution at the temperature of 120 ℃ for 60min, and after the reaction solution is cooled to room temperature, adjusting the pH value of the reaction solution to 3.0 by using 1mol/L hydrochloric acid solution to obtain a modified silica sol hole sealing agent solution; adding 300g of magnesium fluosilicate, 150g of sodium silicate and 50g of potassium carbonate into deionized water, and heating and stirring at 45 ℃ until a colorless transparent solution A is obtained; then, adding 25g of triethanolamine and 25g of 2, 2-dihydroxydiethylamine into absolute ethyl alcohol to prepare a colorless transparent solution B; and finally, adding the hole sealing agent solution, the solution B and 2g of hexadecyl trimethyl ammonium bromide into the solution A, heating and stirring until the hole sealing agent solution, the solution B and the hexadecyl trimethyl ammonium bromide are completely dissolved, adding water to dilute the solution to 1000mL, and cooling the solution to room temperature to obtain the milky anti-carbonization inhibitor.

Example two:

slowly adding 100mL of 6% sodium metaaluminate solution into 250g of acidic silica sol to obtain a mixed solution, carrying out reflux reaction on the mixed solution at the temperature of 150 ℃ for 90min, and after the reaction solution is cooled to room temperature, adjusting the pH value of the reaction solution to 3.0 by using 1mol/L hydrochloric acid solution to obtain a modified silica sol hole sealing agent solution; adding 270g of magnesium fluosilicate, 90g of sodium silicate and 70g of potassium carbonate into deionized water, and heating and stirring at 55 ℃ until a colorless transparent solution A is obtained; then, 70g of triethanolamine is added into absolute ethyl alcohol to prepare a colorless transparent solution B; and finally, adding the hole sealing agent solution, the solution B and 5g of cetyl alcohol polyoxyethylene ether dimethyl octane ammonium chloride into the solution A, heating and stirring until the mixture is completely dissolved, adding water to dilute the mixture to 1000mL, and cooling the mixture to room temperature to obtain the milky anti-carbonization inhibitor.

Example three:

slowly adding 100mL of 8% sodium metaaluminate solution into 250g of acidic silica sol to obtain a mixed solution, carrying out reflux reaction on the mixed solution at the temperature of 135 ℃ for 100min, and after the reaction solution is cooled to room temperature, adjusting the pH value of the reaction solution to 3.0 by using 1mol/L hydrochloric acid solution to obtain a modified silica sol hole sealing agent solution; adding 400g of magnesium fluosilicate, 200g of sodium silicate and 40g of potassium carbonate into deionized water, and heating and stirring at 65 ℃ until a colorless transparent solution A is obtained; then, 40g of 2, 2-dihydroxydiethylamine is added into absolute ethyl alcohol to prepare colorless transparent solution B; and finally, adding the hole sealing agent solution, the solution B and 7g of octadecyl dimethyl benzyl ammonium chloride into the solution A, heating and stirring until the hole sealing agent solution, the solution B and the octadecyl dimethyl benzyl ammonium chloride are completely dissolved, adding water to dilute the solution to 1000mL, and cooling the solution to room temperature to obtain the milky anti-carbonization inhibitor.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.