Concrete, as the largest building material, has developed rapidly. In recent years, high-strength and high-performance concrete has been widely used in engineering. The fluidity of concrete has developed from the previous 70~90mm to the current slump of 180~230mm. Some projects also use self-compacting concrete, and the pumping height is getting higher and higher. However, the fluidity and cohesion of concrete are often incompatible, that is, it is difficult for concrete to maintain high cohesion properties under large flow conditions. In this way, concrete that pursues high fluidity is prone to bleeding and segregation. Moreover, with the gradual depletion of river sand resources and mineral resources in my country, the gradation and fineness of river sand fluctuate greatly, ordinary manufactured sand with poor particle size is used on a large scale, the water retention of cement fluctuates, and high water reduction but The more sensitive polycarboxylic acid-type water-reducing admixtures are constantly being promoted, and the quality control of ready-mixed concrete is facing increasingly severe challenges. The existing concrete anti-segregation agents have a strong flocculation effect, which will cause the concrete to settle quickly and the concrete to lose its flow properties instantly, which is detrimental to the workability of concrete. For this reason, we propose an anti-segregation agent for concrete and its preparation method.
Technical implementation elements:
The purpose of the present invention is to provide an anti-segregation agent for concrete and a preparation method thereof, so as to solve the existing problems of anti-segregation of concrete proposed in the above background technology. The strong flocculation effect of the agent will cause the concrete to settle quickly, causing the concrete to lose its flow properties instantly, which is detrimental to the workability of the concrete.
In order to achieve the above object, the present invention provides the following technical solution: an anti-segregation agent for concrete, the composition of the anti-segregation agent for concrete is as follows:
fly ash 5- 15 parts, mineral powder 5-15 parts, steel fiber 1-2 parts, polyethylene glycol 1-2 parts, polyhydroxy acid water reducing agent 20-30 parts, tackifier 0.8-1.2 parts, coagulant 0.5- 0.9 parts, 200-300 parts of deionized water, several parts of liquid alkali, 5-10 parts of silicone monomer, 3-5 parts of oxidizing agent, and 1-3 parts of reducing agent.
Preferably, the organosilicon monomer is propyltrichlorosilane or vinyltrichlorosilane or fluorosilicone monomer or a mixture of the three.
Preferably, the coagulant is powdered sodium sulfate.
Preferably, the tackifier is PAM, and the PAM is moistened with methanol or ethanol, deionized water is added for stirring, and the mixture is heated to 55 degrees Celsius during stirring to prepare a solution with a concentration of 4%.
Preferably, the oxidizing agent is one or a mixture of hydrogen peroxide, ammonium persulfate, and potassium persulfate.
Preferably, the reducing agent is ammonium persulfate-anhydrous sodium bisulfite or ammonium persulfate-sodium hypophosphite.
Preferably, the alkali solution is sodium hydroxide.
Preferably, the preparation method of the concrete anti-segregation agent includes the following steps:
S1: Mix: combine silicone monomer, deionized water, polyhydroxyacid superplasticizer and polyethylene glycol into the reaction kettle for mixing;
S2: Oxidation: Stir until the mixture in step S1 is evenly mixed, and add an oxidant for oxidation;
S3: Restore: Add fly ash, mineral powder and steel fiber to the oxidation mixture in step S2, and then add the reducing agent;
S4: Neutralization: Add a tackifier to the reduced mixture in step S3 and coagulant, stir continuously until the mixture is uniform, then add liquid caustic soda to adjust the pH so that the pH is between 7-9, and the anti-segregation agent for concrete can be obtained.
Compared with the existing technology, the beneficial effects of the present invention are: the invention adds fly ash, mineral powder and steel fiber to the anti-segregation agent, which can not only improve the compressive strength of concrete, but also It can also effectively improve the working performance and stratification of concrete, improve the segregation resistance of concrete, and reduce the expansion and slump of concrete. PAM is used as a tackifier because PAM has more -NH2. The tackifier has good hydrophilicity, making the concrete hydrophilic, water-retaining, thickening, resistance-reducing and viscosity-increasing. Adding calcium sulfate as a setting accelerator can promote concrete water splashing, accelerate hardening, and promote condensation. The invention has wide sources of raw materials, low cost, green environmental protection and simple operation.
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S1: Mix: combine silicone monomer, Deionized water, polyhydroxyacid superplasticizer and polyethylene glycol are added into the reactor for mixing;
S2: Oxidation: Stir until the mixture in step S1 is evenly mixed, and add oxidant for oxidation;
S3: reduction: add fly ash, mineral powder and steel fiber to the oxidation mixture in step S2, and then add reducing agent;
S4: Neutralization: In step S3 Add tackifier and coagulant to the reduced mixture, stir continuously until evenly stirred, then add liquid caustic soda to adjust the pH so that the pH is between 7-9, and then you can obtain the anti-segregation agent for concrete.
Compared with the existing technology, the beneficial effects of the present invention are: the invention adds fly ash, mineral powder and steel fiber to the anti-segregation agent, which can not only improve the compressive strength of concrete, but also It can also effectively improve the working performance and stratification of concrete, improve the segregation resistance of concrete, and reduce the expansion and slump of concrete. PAM is used as a tackifier because PAM has more -NH2. The tackifier has good hydrophilicity, making the concrete hydrophilic, water-retaining, thickening, resistance-reducing and viscosity-increasing. Adding calcium sulfate as a setting accelerator can promote concrete water splashing, accelerate hardening, and promote condensation. The invention has wide sources of raw materials, low cost, green environmental protection and simple operation. </p
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