Composite crack-resistant lightweight aggregate concrete and preparation method thereof

Abstract

The present invention belongs to the field of concrete technology, and specifically relates to a composite crack-resistant lightweight aggregate concrete and a preparation method thereof. The composite crack-resistant lightweight aggregate concrete comprises the following raw materials by weight: 45-60 parts of cementitious material; 20-30 parts of admixture; 10-15 parts of lightweight aggregate; 2-4 parts of polymer admixture; 1-3 parts of air-entraining agent; and 30-40 parts of water. The preparation method comprises the following steps: first, according to weight ratio, adding cementitious material, admixture, lightweight aggregate, polymer admixture, and half of water into a blender, stirring and mixing them uniformly to obtain a mixed slurry; then, mixing and foaming the air-entraining agent and the remaining water, and then adding the mixture to the mixed slurry and stirring uniformly to obtain the composite crack-resistant lightweight aggregate concrete. The composite crack-resistant lightweight aggregate concrete has good compressive strength and flexural strength, especially excellent crack resistance. After construction, it is lightweight and high-strength, free of cracking and hollowing, and can replace traditional concrete materials. It is widely used in cushioning, insulation, backfill and other projects.

Claims

1. A composite crack-resistant lightweight aggregate concrete, characterized in that: The raw materials include the following parts by weight: 45-60 parts of cementitious materials; 20-30 parts of admixtures; 10-15 parts of lightweight aggregates; 2-4 parts of polymer admixtures; 1-3 parts of air entraining agents; 30-40 parts of water; The air entraining agent is an anionic surfactant; the polymer admixture is composed of 15%-20% by mass of dispersible latex powder, 30%-35% by mass of modified hydroxypropyl methylcellulose, and 45%-55% by mass of sodium silicate; The preparation method of the modified hydroxypropyl methylcellulose is: S1. Add hydroxypropyl methylcellulose to N,N-dimethylformamide, add epichlorohydrin dropwise, raise the temperature to 70-80°C, and react for 2-3 hours to obtain a hydroxypropyl methylcellulose derivative; S2. Add methyl orthosilicate and 3-aminopropyltrimethoxysilane to a mixed solution of deionized water and ethanol, stir evenly, add dilute hydrochloric acid to adjust the pH to 2-4, stir for 2-3 hours, add aqueous ammonia to adjust the pH to 8-10, and obtain a wet gel after condensation. Add an aqueous solution of hydroxypropyl methylcellulose derivative to the wet gel, place at 60-70° C., carry out grafting reaction for 4-6 hours, and dry to obtain modified hydroxypropyl methylcellulose; The preparation method of the anionic surfactant is: (1) Phenbutylamine, triethylamine, and 6-chlorohexanol were added to N,N-dimethylformamide in sequence, the temperature was raised to 50-60°C, and the reaction was carried out for 2-4 hours to obtain compound 1, the structural formula of which is: (2) Compound 1 and 1,3-propyl sultone were added to anhydrous tetrahydrofuran, and a solution of sodium hydrogen in anhydrous tetrahydrofuran was added dropwise. After the addition was complete, the mixture was refluxed for 10-15 hours to obtain an anionic surfactant having the structural formula:

2. A composite crack-resistant lightweight aggregate concrete according to claim 1, characterized in that: The mass ratio of hydroxypropyl methylcellulose to epichlorohydrin in step S1 is 1:0.5-1.

3. The composite crack-resistant lightweight aggregate concrete according to claim 1, characterized in that: In step S2, the mass ratio of methyl orthosilicate, 3-aminopropyltrimethoxysilane, deionized water, and ethanol is 1:0.5-1:2-3:1-2; the mass ratio of 3-aminopropyltrimethoxysilane and hydroxypropyl methylcellulose derivative is 1:1-2.

4. The composite crack-resistant lightweight aggregate concrete according to claim 1, characterized in that: The concentration of the dilute hydrochloric acid in step S2 is 0.5-1 mol / L; the drying is performed by forced air drying at normal pressure, at a drying temperature of 60-80° C., and for a drying time of 12-15 hours.

5. The composite crack-resistant lightweight aggregate concrete according to claim 1, characterized in that: The molar ratio of phenbutylamine, 6-chlorohexanol and triethylamine in step (1) is 1:1.1-1.2:1.5-2.0; the molar ratio of compound 1, 1,3-propyl sultone and sodium hydrogen sulfone in step (2) is 1:1.1-1.2:1.5-2.

0.

6. The composite crack-resistant lightweight aggregate concrete according to claim 1, characterized in that: The gelling material is any one of cement, gypsum and lime or a mixture of several of them.

7. The composite crack-resistant lightweight aggregate concrete according to claim 1, characterized in that: The lightweight aggregate is any one of ceramsite, perlite, EPS particles, mineral rock particles, vermiculite, and phenolic particles, or a mixture of several of them.

8. The composite crack-resistant lightweight aggregate concrete according to claim 1, characterized in that: The admixture is any one of fly ash, mineral powder and silica fume or a mixture of several of them.

9. A method for preparing the composite crack-resistant lightweight aggregate concrete according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: firstly adding the cementitious material, admixture, lightweight aggregate, polymer admixture and half of water into a mixer according to weight ratio, stirring and mixing evenly to obtain a mixed slurry; mixing the air entraining agent and the remaining water evenly to foam, then adding the mixture into the mixed slurry, stirring evenly to obtain the product.

Images