A concrete surface curing material for use in a windy and dry environment and a preparation method thereof

Abstract

The present invention discloses a concrete surface curing material and a preparation method thereof. The concrete surface curing material comprises the following components: 40% to 50% of a biological raw material containing active hydroxyl groups, 0.1% to 1% of ammonium persulfate, 0.05% to 0.1% of ceric ammonium nitrate, 10% to 20% of acrylamide, 5% to 10% of 2-acrylamido-2-methyl-1-propanesulfonic acid, 1% to 5% of N,N-methylenebisacrylamide, 1% to 5% of a pH regulator, and 1% to 10% of a polyether polyol. The concrete surface curing material uses active biomass as a raw material and prepares a cross-linked polymer through a free radical initiation reaction. The cross-linked polymer can quickly form a dense polymer film on the concrete surface, inhibiting water evaporation from the concrete surface, and achieving a water retention rate of over 90%. At the same time, the raw materials used in the product are free of organic residue and volatility, are environmentally friendly, and meet the national low-carbon and environmental protection policy requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of concrete admixtures, and in particular to a concrete surface curing material and a preparation method thereof. Background Art

[0002] After concrete pouring is completed, it needs to be promptly covered or watered for curing within a certain period of time. The curing efficiency of concrete not only affects the growth of early strength of concrete, but also affects the later mechanical properties and durability of concrete. For example, in the windy and dry Sichuan-Tibet region, the concrete surface loses water quickly, causing shrinkage cracks and even cracks on the concrete surface. Traditional curing methods include watering, laying straw bags, and covering with film. The above methods are difficult to implement in water-scarce areas, and the residual plastic film will affect the fragile ecological environment. Curing with curing agents came into being. This technology refers to spraying film-forming chemicals on the surface of concrete after construction, forming a dense and continuous film in a short time, thereby inhibiting the evaporation of water inside the concrete and promoting the full hydration of the cementitious material.

[0003] Currently used curing agents are categorized into inorganic and organic types based on their active ingredients. Inorganic curing agents are primarily silicate solutions based on sodium silicate. Their principle is to utilize the permeability and chemical reactivity of inorganic silicates to penetrate the pores of the cement concrete surface, reacting with cement hydration products to form a water-insoluble colloidal film. This occludes the pores and prevents water evaporation, achieving the desired curing effect. However, these curing agents suffer from low water retention (typically only 20-35%) and poor film-forming properties. Organic curing agents are a class of polymer materials. After drying and evaporation, their molecules aggregate into an impermeable film that covers the cement concrete surface, preventing water evaporation. These curing agents primarily include resins, latexes, and emulsions. Resins often contain volatile solvents, which pollute the environment and harm human health. Latex curing agents are expensive and difficult to remove after curing, hindering subsequent construction. While emulsions can overcome these drawbacks, they also suffer from low spray thickness and poor film density. Summary of the Invention

[0004] To address these issues, the present invention provides an environmentally friendly curing agent made from bio-based raw materials. This curing agent is solvent-free and environmentally friendly. Upon spraying, it quickly forms a film on the concrete surface, with good film continuity and tightness, and a water retention rate exceeding 90%. It offers excellent curing effects on concrete surfaces in windy and dry environments without negatively impacting the ecological environment.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention to solve the technical problem is:

[0006] A concrete surface curing material, specifically comprising the following raw materials in percentage by mass:

[0007] 40% to 50% of biological raw materials containing active hydroxyl groups, 0.1% to 1% of ammonium persulfate, 0.05% to 0.1% of ceric ammonium nitrate, 10% to 20% of acrylamide, 5% to 10% of 2-acrylamido-2-methyl-1-propanesulfonic acid, 1% to 5% of N,N'-methylenebisacrylamide, 1% to 5% of pH regulator, and 1% to 10% of polyether polyol.

[0008] As a preference, the biological raw material containing active hydroxyl groups is at least one of chitosan, lignin, and starch, with chitosan being particularly preferred.

[0009] The present invention provides a method for preparing a concrete surface curing material, which specifically comprises the following steps:

[0010] S1: 40% to 50% of the biological raw material containing active hydroxyl groups, 1% to 5% of a pH adjuster, 0.05% to 0.1% of ammonium persulfate, 5% to 10% of acrylamide, and 20% to 30% of deionized water are mixed, heated to 60 to 70° C., and stirred to prepare a base solution A;

[0011] S2: 0.05% to 0.1% of ammonium persulfate, 5% to 10% of acrylamide, 5% to 10% of 2-acrylamido-2-methyl-1-propanesulfonic acid, 1% to 5% of N,N'-methylenebisacrylamide, and 0.05% to 0.1% of ceric ammonium nitrate are mixed, and 10% to 20% of deionized water are added to prepare solution B. Solution B is added dropwise to the base solution A prepared in S1 for 1.5 to 2 hours. After the addition is completed, the solution is kept warm at 60°C for 2 to 3 hours to prepare solution C;

[0012] S3: Adding 1% to 10% of the polyether polyol to the solution C obtained in S2 and adding water to a solids content of 5% to 10% to obtain the concrete surface curing agent. 4. The surface curing material of claim 1, wherein the pH adjuster is selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, p-toluenesulfonic acid, sodium hydroxide, potassium hydroxide, and ammonia.

[0013] Preferably, the chitosan is one of medium-deacetylated chitosan, high-deacetylated chitosan, and ultra-high-deacetylated chitosan, with a deacetylation degree of more than 70%, preferably high-deacetylated chitosan.

[0014] As a preferred embodiment, the lignin is one of guaiacol lignin sulfonate, guaiacol-sinapyl alcohol lignin sulfonate, and guaiacol-sinapyl alcohol-p-hydroxyphenyl lignin sulfonate, among which guaiacol-sinapyl alcohol-p-hydroxyphenyl lignin sulfonate is preferred.

[0015] As a preference, the starch is one of tapioca starch, potato starch, corn starch and wheat starch, among which tapioca starch is preferred.

[0016] As a preference, the molecular weight of the polyether polyol is 400-4000 g / mol, preferably 1000-4000 g / mol, particularly preferably 1500-3000 g / mol.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. This patented product uses active biomass as raw material and prepares cross-linked polymers through free radical initiation reactions. It can quickly form a dense polymer film on the concrete surface, inhibiting the evaporation of water on the concrete surface. At the same time, the raw materials used in this product have no organic residues and volatility, and are environmentally friendly.

[0019] 2. Compared with conventional inorganic curing agents with a water retention rate of only about 65%, this patented product can form a continuous and dense film with a water retention rate of more than 90%; and compared with organic emulsion curing agents with solvent residues, this patented product has no solvent volatilization.

[0020] 3. Polyether polyols have a high surface tension, which can enhance the penetration ability of synthetic bio-based polymers in the concrete surface. At the same time, the hydroxyl group has a certain water retention capacity, which can further enhance the ability of the curing material to inhibit water evaporation.

[0021] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0022] The present application is further described in detail below in conjunction with the embodiments, preparation examples and comparative examples. The raw materials involved in the present application can be obtained commercially. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0023] Example 1:

[0024] S1: Take 40 parts of medium-deacetylated chitosan, 10 parts of hydrochloric acid, 0.05 parts of ceric ammonium nitrate, 10 parts of acrylamide, and 20 parts of deionized water, heat to 60°C and stir for 10 minutes;

[0025] S2: Prepare a solution by taking 0.1 parts of ammonium persulfate, 5 parts of acrylamide, 5 parts of 2-acrylamido-2-methyl-1-propanesulfonic acid, 1 part of N,N-methylenebisacrylamide, 0.05 parts of ceric ammonium nitrate, and 15 parts of deionized water. Add this solution dropwise to S1 over 1.5 hours, and keep warm at 60°C for 2 hours.

[0026] S3: Add 5 parts of polyether polyol with a molecular weight of 2000 g / mol to the liquid prepared in S2, and add 1200 parts of water to a solid content of 5% to obtain a concrete surface curing agent.

[0027] Example 2:

[0028] S1: Take 45 parts of sinapine-sinapine-p-hydroxyphenyl lignin sulfonate, 5 parts of hydrochloric acid, 0.05 parts of ceric ammonium nitrate, 10 parts of acrylamide, and 20 parts of deionized water, heat to 70°C, and stir for 10 minutes;

[0029] S2: Prepare a solution by taking 0.1 parts of ammonium persulfate, 10 parts of acrylamide, 5 parts of 2-acrylamido-2-methyl-1-propanesulfonic acid, 1 part of N,N-methylenebisacrylamide, 0.05 parts of ceric ammonium nitrate, and 15 parts of deionized water. Add this solution dropwise to S1 over 1.5 hours, and keep warm at 60°C for 2 hours.

[0030] S3: Add 5 parts of polyether polyol with a molecular weight of 2000 g / mol to the liquid prepared in S2, and add 1200 parts of water to a solid content of 5% to obtain a concrete surface curing agent.

[0031] Example 3:

[0032] S1: Take 50 parts of cassava starch, 5 parts of hydrochloric acid, 0.05 parts of ceric ammonium nitrate, 10 parts of acrylamide, and 20 parts of deionized water, heat to 60°C and stir for 30 minutes;

[0033] S2: Prepare a solution by taking 0.1 parts of ammonium persulfate, 10 parts of acrylamide, 5 parts of 2-acrylamido-2-methyl-1-propanesulfonic acid, 1 part of N,N-methylenebisacrylamide, 0.05 parts of ceric ammonium nitrate, and 15 parts of deionized water. Add this solution dropwise to S1 over 1.5 hours, and keep warm at 60°C for 2 hours.

[0034] S3: Add 5 parts of polyether polyol with a molecular weight of 2000 g / mol to the liquid prepared in S2, and add 1200 parts of water to a solid content of 5% to obtain a concrete surface curing agent.

[0035] Example 4:

[0036] S1: Take 40 parts of highly deacetylated chitosan, 10 parts of hydrochloric acid, 0.1 parts of ceric ammonium nitrate, 10 parts of acrylamide, and 20 parts of deionized water, heat to 60°C, and stir for 20 minutes;

[0037] S2: Prepare a solution by taking 0.1 parts of ammonium persulfate, 5 parts of acrylamide, 5 parts of 2-acrylamido-2-methyl-1-propanesulfonic acid, 0.5 parts of N,N-methylenebisacrylamide, 0.05 parts of ceric ammonium nitrate, and 20 parts of deionized water. Add this solution dropwise to S1 over 1.5 hours, and keep warm at 60°C for 2 hours.

[0038] S3: Add 5 parts of polyether polyol with a molecular weight of 2000 g / mol to the liquid prepared in S2, and add 600 parts of water to a solid content of 10% to obtain a concrete surface curing agent.

[0039] Example 5:

[0040] S1: Take 40 parts of highly deacetylated chitosan, 10 parts of hydrochloric acid, 0.1 parts of ceric ammonium nitrate, 10 parts of acrylamide, and 20 parts of deionized water, heat to 60°C, and stir for 20 minutes;

[0041] S2: Prepare a solution by adding 0.1 parts of ammonium persulfate, 5 parts of acrylamide, 5 parts of 2-acrylamido-2-methyl-1-propanesulfonic acid, 0.05 parts of ceric ammonium nitrate, and 20 parts of deionized water. Add the solution dropwise to S1 over 1.5 hours, and keep the mixture at 60°C for 2 hours.

[0042] S3: Add 5 parts of polyether polyol with a molecular weight of 2000 g / mol to the liquid prepared in S2, and add 600 parts of water to a solid content of 10% to obtain a concrete surface curing agent.

[0043] Example 6:

[0044] S1: Take 40 parts of highly deacetylated chitosan, 10 parts of hydrochloric acid, 0.1 parts of ceric ammonium nitrate, 10 parts of acrylamide, and 20 parts of deionized water, heat to 60°C, and stir for 20 minutes;

[0045] S2: Prepare a solution by taking 0.1 parts of ammonium persulfate, 5 parts of acrylamide, 5 parts of 2-acrylamido-2-methyl-1-propanesulfonic acid, 0.5 parts of N,N-methylenebisacrylamide, 0.05 parts of ceric ammonium nitrate, and 20 parts of deionized water. Add this solution dropwise to S1 over 1.5 hours, and keep warm at 60°C for 2 hours.

[0046] S3: Add 5 parts of polyether polyol with a molecular weight of 4000 g / mol to the liquid prepared in S2, and add 600 parts of water to a solid content of 10% to obtain a concrete surface curing agent.

[0047] Example 7:

[0048] S1: Take 40 parts of guaiacol lignin sulfonate, 10 parts of hydrochloric acid, 0.1 parts of ceric ammonium nitrate, 10 parts of acrylamide, and 20 parts of deionized water, heat to 60°C, and stir for 20 minutes;

[0049] S2: Prepare a solution by taking 0.1 parts of ammonium persulfate, 5 parts of acrylamide, 5 parts of 2-acrylamido-2-methyl-1-propanesulfonic acid, 0.5 parts of N,N-methylenebisacrylamide, 0.05 parts of ceric ammonium nitrate, and 20 parts of deionized water. Add this solution dropwise to S1 over 1.5 hours, and keep warm at 60°C for 2 hours.

[0050] S3: Add 5 parts of polyether polyol with a molecular weight of 4000 g / mol to the liquid prepared in S2, and add 600 parts of water to a solid content of 10% to obtain a concrete surface curing agent.

[0051] Example 8:

[0052] S1: Take 40 parts of corn starch, 10 parts of hydrochloric acid, 0.1 parts of ceric ammonium nitrate, 10 parts of acrylamide, and 20 parts of deionized water, heat to 60°C and stir for 20 minutes;

[0053] S2: Prepare a solution by taking 0.1 parts of ammonium persulfate, 5 parts of acrylamide, 5 parts of 2-acrylamido-2-methyl-1-propanesulfonic acid, 0.5 parts of N,N-methylenebisacrylamide, 0.05 parts of ceric ammonium nitrate, and 20 parts of deionized water. Add this solution dropwise to S1 over 1.5 hours, and keep warm at 60°C for 2 hours.

[0054] S3: Add 5 parts of polyether polyol with a molecular weight of 4000 g / mol to the liquid prepared in S2, and add 600 parts of water to a solid content of 10% to obtain a concrete surface curing agent.

[0055] Application Effect

[0056] The effective water retention, drying time, and film-forming water solubility of the curing agent were tested according to JC901-2002 "Cement Concrete Curing Agents." The impact of the curing agent on concrete cracking performance was tested according to T0573-2020 "Test Method for Early Cracking Sensitivity of Cement Concrete." The VOC content of the curing agent was tested according to GB30981-2020 "VOC Testing of Industrial Coatings." Two typical market curing agents, S-1 and S-2, were selected for comparative testing. The results are shown in Table 1:

[0057] Table 1 Effect of curing agent application

[0058] curing agent Water retention rate Drying time Film-forming water solubility Crack reduction rate VOC / g / L S-1 68％ 120 minutes Completely dissolved 60％ 60 S-2 76％ 65min Partially dissolved 65％ 70 Example 1 87％ 40min Insoluble 81％ 15 Example 2 82％ 50min Insoluble 78％ 15 Example 3 86％ 30min Insoluble 80％ 15 Example 4 92％ 35min Insoluble 85％ 15 Example 5 82％ 60min A small amount of dissolution 74％ 15 Example 6 90％ 35min Insoluble 85％ 15 Example 7 87％ 50min Insoluble 82％ 15 Example 8 85％ 65min Insoluble 83％ 15

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A concrete surface curing material, characterized in that: The concrete surface curing material comprises the following raw materials in percentage by mass: 40% to 50% of biological raw materials containing active hydroxyl groups, 0.1% to 1% of ammonium persulfate, 0.05% to 0.1% of ceric ammonium nitrate, 10% to 20% of acrylamide, 5% to 10% of 2-acrylamido-2-methyl-1-propanesulfonic acid, 1% to 5% of N,N'-methylenebisacrylamide, 1% to 5% of pH regulator, and 1% to 10% of polyether polyol; The molecular weight of the polyether polyol is 1000 to 4000 g / mol.

2. The concrete surface curing material according to claim 1, characterized in that: The biological raw material containing active hydroxyl groups is at least one of chitosan, lignin and starch.

3. The concrete surface curing material according to claim 1, characterized in that: The pH regulator is at least one of hydrochloric acid, sulfuric acid, nitric acid, p-toluenesulfonic acid, sodium hydroxide, potassium hydroxide, and ammonia water.

4. The concrete surface curing material according to claim 2, characterized in that: The chitosan is at least one of medium-deacetylated chitosan, high-deacetylated chitosan, and ultra-high-deacetylated chitosan, with a deacetylation degree of more than 70%.

5. The concrete surface curing material according to claim 2, characterized in that: The lignin is at least one of guaiacol lignin sulfonate, guaiacol-sinapyl alcohol lignin sulfonate, and guaiacol-sinapyl alcohol-p-hydroxyphenyl lignin sulfonate.

6. The concrete surface curing material according to claim 2, characterized in that: The starch is at least one of tapioca starch, potato starch, corn starch and wheat starch.

7. A method for preparing the concrete surface curing material according to claim 1, characterized in that: The following steps are involved: S1: 40% to 50% of the biological raw material containing active hydroxyl groups, 1% to 5% of a pH adjuster, 0.05% to 0.1% of ammonium persulfate, 5% to 10% of acrylamide, and 20% to 30% of deionized water are mixed, heated to 60 to 70° C., and stirred to prepare a base solution A; S2: 0.05% to 0.1% of ammonium persulfate, 5% to 10% of acrylamide, 5% to 10% of 2-acrylamido-2-methyl-1-propanesulfonic acid, 1% to 5% of N,N'-methylenebisacrylamide, and 0.05% to 0.1% of ceric ammonium nitrate are mixed, and 10% to 20% of deionized water are added to prepare solution B. Solution B is added dropwise to the base solution A prepared in S1 for 1.5 to 2 hours. After the addition is completed, the solution is kept warm at 60°C for 2 to 3 hours to prepare solution C; S3: adding 1% to 10% of the polyether polyol to the solution C obtained in S2, and adding water to the solution solid content of 5% to 10% to obtain the concrete surface curing agent.