Admixture for recycled aggregate concrete and preparation method thereof

A recycled aggregate and concrete technology, applied in the field of concrete admixtures, can solve the problems of rough recycled aggregate structure, large structural voids, insufficient density of recycled aggregate concrete, etc.

Active Publication Date: 2021-04-20
中建西部建设北方有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of the above-mentioned related technologies, the inventor believes that in the process of improving the strength of the existing admixtures used in recycled aggregates, due to the large internal structure of recycled aggregates, excessive oxygen is easy to accumulate, resulting in the compactness of recycled aggregate concrete. At the same time, after the recycled aggregate is directly mixed into the concrete, the workability and fluidity of the concrete will be reduced due to the rough structure of the recycled aggregate.

Method used

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  • Admixture for recycled aggregate concrete and preparation method thereof
  • Admixture for recycled aggregate concrete and preparation method thereof
  • Admixture for recycled aggregate concrete and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Mix 200mL of hydrophilic silica with a solid content of 15% and 2000mL of polyvinyl alcohol solution with a mass fraction of 5% and heat it in an oil bath at 100°C for 2 hours, then let it stand and cool to room temperature to obtain a mixed solution; use 5mL of 0.5mol / L sodium hydroxide solution was added dropwise to the mixed solution, and the dropping rate was controlled at 2mL / min. After the dropwise addition was completed, the suspension was collected; then 20mL of silane coupling agent was mixed with 200mL of the suspension to adjust the pH After reaching 10.0°C, heat-preserve and react at 40°C for 20 hours, collect the reaction liquid and place it in a rotary evaporation at 45°C, and when it evaporates to 1 / 3 of the volume of the reaction liquid, a hydrophilic porous silica sol is obtained;

[0038] Take 800mL of deionized water, 10g of polyvinylpyrrolidone, 6g of sodium erythorbate, 6g of sodium hexametaphosphate, 3g of D-sodium gluconate and 1g of zinc sulfate ...

Embodiment 2

[0043] Mix 225mL of hydrophilic silica with a solid content of 15% and 2500mL of polyvinyl alcohol solution with a mass fraction of 5% and heat it in an oil bath at 105°C for 2 hours, then let it stand and cool to room temperature to obtain a mixed solution; use 7mL of 0.5mol / L sodium hydroxide solution was added dropwise to the mixed solution, and the dropping rate was controlled at 2mL / min. After the dropwise addition was completed, the suspension was collected; then 27mL of silane coupling agent was mixed with 350mL of the suspension to adjust the pH After reaching 10.0°C, heat-preserve and react at 42°C for 22 hours, collect the reaction solution and place it in a rotary evaporation at 52°C, and when it evaporates to 1 / 3 of the volume of the reaction solution, a hydrophilic porous silica sol is obtained;

[0044] Take 900mL of deionized water, 12g of polyvinylpyrrolidone, 7g of sodium erythorbate, 7g of sodium hexametaphosphate, 4g of D-sodium gluconate and 2g of zinc sulf...

Embodiment 3

[0049] Take 250mL of hydrophilic silica with a solid content of 15% and mix 3000mL of 5% polyvinyl alcohol solution with a mass fraction of 3000mL, heat it in an oil bath at 110°C for 3 hours, and let it stand to cool to room temperature to obtain a mixed solution; use 8mL of 0.5mol / L sodium hydroxide solution was added dropwise to the mixed solution, and the dropping rate was controlled at 3mL / min. After the dropwise addition was completed, the suspension was collected; then 35mL silane coupling agent was mixed with 500mL suspension to adjust the pH After reaching 10.0°C, heat-preserve and react at 45°C for 24 hours, collect the reaction solution and place it in a rotary evaporation at 60°C, and when it evaporates to 1 / 3 of the volume of the reaction solution, a hydrophilic porous silica sol is obtained;

[0050] Take 1000mL of deionized water, 15g of polyvinylpyrrolidone, 8g of sodium erythorbate, 8g of sodium hexametaphosphate, 5g of D-sodium gluconate and 2g of zinc sulfat...

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Abstract

The invention relates to the field of concrete admixtures, and particularly discloses an admixture for recycled aggregate concrete and a preparation method of the admixture, and the admixture for recycled aggregate concrete comprises the following substances in parts by weight: 30-50 parts of a sulfamate water reducing agent, 20-30 parts of a polycarboxylic acid water reducing agent, 10-15 parts of nano silicon dioxide sol and 20-45 parts of water, wherein the nano silicon dioxide sol comprises hydrophilic solid silicon dioxide sol and hydrophilic porous silicon dioxide sol which are mixed at equal molar mass. The water reducing agent and the nano silicon dioxide are added into the admixture, the slump retaining effect of the concrete is improved by adding the water reducing agent firstly, and then the solid nano silicon dioxide sol and the porous nano silicon dioxide sol are compounded to serve as a filler of an internal pore structure of the recycled aggregate concrete, so that the compact strength of a concrete structure is improved; the hydration degree of the cement is reduced, and the workability, flowability and compactness of the recycled aggregate concrete are improved.

Description

technical field [0001] The application relates to the field of concrete admixtures, more specifically, it relates to an admixture for recycled aggregate concrete and a preparation method thereof. Background technique [0002] The development and application of construction waste as recycled aggregate, on the one hand, solves the problem of difficult disposal of a large amount of waste concrete; on the other hand, it can reduce the consumption of natural aggregate in the construction industry, thereby reducing the mining of natural sand and gravel, and fundamentally solve The increasing shortage of natural aggregates and the damage to the ecological environment caused by the mining of a large amount of sand and gravel protect the living environment of human beings and meet the requirements of sustainable development. [0003] Compared with ordinary concrete, the main difference between recycled concrete is the difference between recycled aggregate and natural aggregate. The ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B24/26
Inventor 王敏张凯峰孟刚王军罗作球姚源童小根王佳敏胡宇博
Owner 中建西部建设北方有限公司
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