Concrete surface reinforcing agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of building materials, and particularly relates to a concrete surface reinforcing agent as well as a preparation method and application thereof. The concrete surface reinforcing agent is prepared from the following raw material components: sulfur-containing superfine iron tailings, nano gypsum, nano calcium sulfate, monotridecafluorooctyl ether and water. The molar ratio of aluminum to sulfur in the mixture is 1: 3; the mole ratio of aluminum to calcium is 1: 6. The formula design is reasonable, the surface tension of the whole solution is reduced through the monotridecafluorooctyl ether, and the monotridecafluorooctyl ether can permeate into gaps in the surface of concrete more easily; after the reinforcing agent infiltrated into the gaps is in contact with an alkaline solution in the concrete curing process, the added tailings, calcium sulfate and calcium carbonate slowly chemically react to generate ettringite crystals, and the ettringite crystals gradually grow to generate volume expansion to fill the original gaps in the concrete, so that the surface of the concrete is densified, and the durability and the impermeability of the concrete are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and specifically relates to a concrete surface enhancer and a preparation method and application thereof. Background Art

[0002] Sulfur-containing ultrafine iron tailings are mining solid wastes formed after pyrite mining and secondary beneficiation. They have the following characteristics: 1) small particle size, less than 250 mesh; small particle size makes it impossible to use sulfur-containing ultrafine iron tailings as concrete aggregate; 2) contains a certain proportion of iron sulfide and ferrous sulfide. When sulfide is used in concrete, it will undergo a slow oxidation reaction and volume expansion when it comes into contact with water, causing the concrete to expand or crack, reducing the strength and durability of the concrete. Therefore, people have been looking for effective ways to harmlessly and comprehensively utilize sulfur-containing ultrafine iron tailings.

[0003] Concrete surface enhancers are a class of chemical or physical materials designed specifically to improve the surface properties of concrete. Their main purpose is to enhance the durability, impermeability, crack resistance and aesthetics of concrete. By interacting with the concrete surface, these enhancers can improve the physical and chemical properties of concrete, thereby improving its performance in different environments.

[0004] After searching, the Chinese patent literature with publication number CN111170765A mentions a concrete surface enhancer and its preparation method, which is mainly composed of a variety of organic and inorganic materials, and can improve the durability, impermeability and crack resistance of concrete. The raw material is to form a dense protective film by effectively filling the tiny pores on the surface of the concrete to prevent the intrusion of moisture and chemicals. The Chinese patent literature with publication number CN116606163A mentions a new type of water-based concrete surface enhancer, which is mainly composed of water-based resin and functional additives. While improving the strength and durability of the concrete surface, the enhancer has good environmental protection and low volatile organic compound (VOC) emissions. However, after searching, there is no related report on the use of sulfur-containing ultrafine iron tailings to prepare concrete surface enhancers.

[0005] In view of this, the inventors hope to design a new concrete surface enhancer containing sulfur-containing ultrafine iron tailings, which can effectively enhance the durability and impermeability of concrete; at the same time, it provides a new way to utilize sulfur-containing ultrafine iron tailings. Summary of the invention

[0006] The purpose of the present invention is to overcome the above-mentioned problems existing in the traditional technology and provide a concrete surface enhancer and a preparation method and application thereof. The present invention uses sulfur-containing ultrafine iron tailings (less than 250 meshes) which are difficult to use in the building materials industry as the main raw material, and can effectively enhance the durability and impermeability of concrete by adding other additives to work together; at the same time, it provides a new way to utilize sulfur-containing ultrafine iron tailings.

[0007] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0008] The present invention provides a concrete surface enhancer, the raw material components of which include sulfur-containing ultrafine iron tailings, nano gypsum, nano calcium sulfate, monotridecafluorooctyl ether and water;

[0009] The molar ratio of aluminum to sulfur in the mixture of sulfur-containing ultrafine iron tailings and nano-gypsum is 1:3;

[0010] The molar ratio of aluminum to calcium in the mixture of sulfur-containing ultrafine iron tailings, nano-gypsum and nano-calcium sulfate is 1:6;

[0011] In parts by mass, the sulfur-containing ultrafine iron tailings has a mass of 10 parts. After the sulfur-containing ultrafine iron tailings, nano-gypsum and nano-calcium sulfate are mixed, water is added to make up to 1000 parts; the monotridecafluorooctyl ether has a mass of 3 to 5 parts.

[0012] The present invention also provides a method for preparing a concrete surface enhancer, comprising the following steps:

[0013] 1) Grind the sulfur-containing ultrafine iron tailings to 3000 mesh and determine the calcium, aluminum and sulfur contents therein;

[0014] 2) taking 10 portions of ultrafine sulfur-containing ultrafine iron tailings, adding a certain amount of nano-gypsum according to the amount of aluminum therein, so that the molar ratio of aluminum to sulfur in the mixture is 1:3;

[0015] 3) adding a certain amount of nano calcium carbonate to the mixture obtained in step 2) so that the molar ratio of aluminum to calcium in the mixture is 1:6;

[0016] 4) Add water to the mixture obtained in step 3) to make up to 1000 parts; then add 3 to 5 parts of monotridecafluorooctyl ether thereto, stir evenly, and obtain the product.

[0017] Furthermore, in step 1), the sulfur-containing ultrafine iron tailings are mining solid wastes formed after pyrite mining and secondary beneficiation, and have a particle size of less than 250 meshes, and contain a certain proportion of calcium, aluminum and sulfur.

[0018] Furthermore, in step 2), the nano gypsum is dihydrate gypsum.

[0019] Furthermore, in step 4), the amount of the monotridecafluorooctyl ether used is related to the pH value of water.

[0020] Furthermore, when the pH value of the water is greater than 7, the dosage of the monotridecafluorooctyl ether is 3‰; when the pH value of the water is 7, the dosage of the monotridecafluorooctyl ether is 4‰; when the pH value of the water is less than 7, the dosage of the monotridecafluorooctyl ether is 5‰.

[0021] The invention also provides application of a concrete surface enhancer in concrete.

[0022] Furthermore, in the above application, the concrete surface enhancer is sprayed on the concrete surface seven days after the concrete is poured.

[0023] The beneficial effects of the present invention are:

[0024] The formula of the invention is reasonably designed. The surface tension of the entire solution is reduced by monotridecafluorooctyl ether, so that the reinforcing agent can more easily penetrate into the gaps on the surface of the concrete. After the reinforcing agent that has penetrated into the gaps contacts the alkaline solution in the concrete maturation process, the added tailings, calcium sulfate and calcium carbonate slowly undergo a chemical reaction to generate ettringite crystals that gradually grow and expand in volume, thus filling up the original gaps in the concrete and densifying the surface thereof, thereby improving the durability and impermeability of the concrete.

[0025] Of course, any product implementing the present invention does not necessarily need to achieve all of the above advantages at the same time. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] Taking the ultrafine sulfur-containing iron tailings of Maanshan pyrite mine as an example, the XRF spectrum analysis results show that the mass ratios of calcium oxide, aluminum oxide and sulfur are 10.03, 9.59 and 0.375 parts per 100 parts respectively.

[0029] This embodiment provides a concrete surface enhancer, and the specific preparation steps are as follows:

[0030] 1) Grinding the ultrafine sulfur-containing iron tailings to 3000 mesh;

[0031] 2) taking 10 parts of the ultrafine iron tailings described in step 1, adding 3.2 parts of nano gypsum thereto and mixing evenly;

[0032] 3) adding 3.85 parts of nano calcium carbonate to the mixture in step 2 and mixing well;

[0033] 4) Add water to the mixture in step 3 to make up to 1000 parts;

[0034] 5) Add 3‰ of monotridecafluorooctyl ether to the mixture obtained in step 4 and stir evenly to obtain the product. Spray the product on a C40 concrete block after aging for seven days to obtain sample 1.

[0035] Example 2

[0036] Taking the ultrafine sulfur-containing iron tailings of Maanshan pyrite mine as an example, the XRF spectrum analysis results show that the mass ratios of calcium oxide, aluminum oxide and sulfur are 10.03, 9.59 and 0.375 parts per 100 parts respectively.

[0037] This embodiment provides a concrete surface enhancer, and the specific preparation steps are as follows:

[0038] 1) Grinding the ultrafine sulfur-containing iron tailings to 3000 mesh;

[0039] 2) taking 10 parts of the ultrafine iron tailings described in step 1, adding 3.2 parts of nano gypsum thereto and mixing evenly;

[0040] 3) adding 3.85 parts of nano calcium carbonate to the mixture in step 2 and mixing well;

[0041] 4) Add water to the mixture in step 3 to make up to 1000 parts;

[0042] 5) Add 5‰ of monotridecafluorooctyl ether to the mixture obtained in step 4 and stir evenly to obtain the product. Spray the product on a C40 concrete block after aging for seven days to obtain sample 2.

[0043] Comparative Example

[0044] In order to compare the effects before and after implementation, C40 concrete blocks from the same production batch as used in the above embodiment were used as a comparative example, and the obtained sample was named: Sample 3.

[0045] The following properties were tested on the samples of the embodiments and comparative examples, and the results are shown in Table 1.

[0046] Rebound value: The rebound value of the sample after 28 days is tested according to the standard method of "Technical Specification for Testing Concrete Compressive Strength by Rebound Method" JGJ / T23-2001. Durability test: Cut and test the chloride ion permeability of the sample concrete according to the method of "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009). Chloride ion permeability indicates the rate at which chloride ions penetrate into the concrete, which is expressed by the chloride ion diffusion coefficient. Abrasion resistance test: Cut and test the abrasion resistance of the sample according to "Test Method for Abrasion Resistance of Concrete and Its Products" (GB / T 16925-1997).

[0047] Table 1

[0048] Group Rebound value(MPa) <![CDATA[Chloride ion diffusion coefficient (×10 -12 m 2 / s)]]> Abrasion resistance Sample 1 44.7 1.394 3.7 Sample 2 43.5 1.412 3.6 Sample 3 41.3 1.476 3.1

[0049] It can be seen from the data in Table 1 that after using the product of the present invention, the rebound value, chloride ion diffusion coefficient and wear resistance of concrete are all improved, indicating that the durability and impermeability of concrete are improved. These effects are due to the clever use of the chemical composition of tailings and the pH characteristics of the internal environment of concrete, so that the activated tailings that have infiltrated and the active gypsum and calcium carbonate react chemically in an alkaline environment, and the synergistic effect of generating ettringite crystals with a hardness higher than that of gangue to close the gaps produces an effect.

[0050] The product of the present invention should be used after the concrete has been matured for 7 days. If it is used too early, the concrete itself is not matured enough and the strength is not enough. Then the ettringite crystals grow and expand and may destroy the original concrete structure. If the water used to prepare the reinforcing agent is alkaline, the amount of monotridecafluorooctyl ether is 3‰; if the water is acidic, the amount of monotridecafluorooctyl ether is increased to 5‰.

[0051] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A concrete surface enhancer, characterized in that: Its raw material components include sulfur-containing ultrafine iron tailings, nano-gypsum, nano-calcium sulfate, monotridecafluorooctyl ether and water; The molar ratio of aluminum to sulfur in the mixture of sulfur-containing ultrafine iron tailings and nano-gypsum is 1:3; The molar ratio of aluminum to calcium in the mixture of sulfur-containing ultrafine iron tailings, nano-gypsum and nano-calcium sulfate is 1:6; In parts by mass, the sulfur-containing ultrafine iron tailings has a mass of 10 parts. After the sulfur-containing ultrafine iron tailings, nano-gypsum and nano-calcium sulfate are mixed, water is added to make up to 1000 parts; the monotridecafluorooctyl ether has a mass of 3 to 5 parts.

2. The method for preparing a concrete surface enhancer according to claim 1, characterized in that: The steps include: 1) Grind the sulfur-containing ultrafine iron tailings to 3000 mesh and determine the calcium, aluminum and sulfur contents therein; 2) taking 10 portions of ultrafine sulfur-containing ultrafine iron tailings, adding a certain amount of nano-gypsum according to the amount of aluminum therein, so that the molar ratio of aluminum to sulfur in the mixture is 1:3; 3) adding a certain amount of nano calcium carbonate to the mixture obtained in step 2) so that the molar ratio of aluminum to calcium in the mixture is 1:6; 4) Add water to the mixture obtained in step 3) to make up to 1000 parts; then add 3 to 5 parts of monotridecafluorooctyl ether thereto, stir evenly, and obtain the product.

3. The preparation method according to claim 2, characterized in that: In step 1), the sulfur-containing ultrafine iron tailings are mining solid wastes formed after pyrite mining and secondary beneficiation, and have a particle size of less than 250 meshes. They also contain a certain proportion of calcium, aluminum and sulfur.

4. The preparation method according to claim 2, characterized in that: In step 2), the nano gypsum is dihydrate gypsum.

5. The preparation method according to claim 2, characterized in that: In step 4), the amount of the monotridecafluorooctyl ether used is related to the pH value of water.

6. The preparation method according to claim 5, characterized in that: When the pH value of the water is greater than 7, the dosage of the monotridecafluorooctyl ether is 3‰; when the pH value of the water is 7, the dosage of the monotridecafluorooctyl ether is 4‰; when the pH value of the water is less than 7, the dosage of the monotridecafluorooctyl ether is 5‰.

7. Use of the concrete surface enhancer according to claim 1 in concrete.

8. The use according to claim 7, characterized in that: The concrete surface enhancer is sprayed on the concrete surface seven days after concrete pouring.