Application of a mud-resistant and slump-preserving water-reducing agent in construction solid waste recycled aggregate concrete

Abstract

The invention discloses an application of a mud-resistant slump-retaining type water reducing agent to building solid waste recycled aggregate concrete and further discloses the building solid waste recycled aggregate concrete containing the mud-resistant slump-retaining type water reducing agent. On the basis of the principle of polymer structure design, a water-soluble polymer PEI (polyethyleneimine) is modified through a Mannich reaction, phosphorous acid functional groups are introduced, and the slump-retaining type water reducing agent with special tolerance to mud and recycled aggregatepowder is synthesized. The molecular structure of the product contains a large amount of amino with positive charges and is in a cluster shape, the cluster structure is physically cross-linked, a complexing adsorption layer is formed on the surface of cement particles, excellent slump-retaining capacity is obtained, and defects of poor dispersity and low water-reducing rate of a slump-retaining type polycarboxylate superplasticizer in the market are overcome; the mud-resistant slump-retaining type water reducing agent is used independently or compounded with other functional polycarboxylate superplasticizers for use and has good water reducing and slump retaining performance for the building solid waste recycled aggregate concrete.

Description

technical field [0001] The invention relates to the technical field of concrete, in particular to the application of a mud-resistant and slump-preserving water reducer in construction solid waste recycled aggregate concrete. Background technique [0002] Concrete is the second most consuming material on earth after water. The annual consumption in the world exceeds 20 billion tons. While the consumption of concrete is huge, it also causes social and environmental problems of resource consumption and waste disposal. [0003] my country is the country with the largest number of newly built buildings in the world, and it is also the country with the largest number of old buildings demolished every year in the world. According to preliminary estimates, the demolition of buildings per square meter will generate about 1 ton of construction solid waste. The rapid development of cities will inevitably produce a large amount of construction solid waste, and proper disposal of constru...

AI Technical Summary

Problems solved by technology

[0014] 1. High water demand and high admixture content;

[0015] 2. Large loss of slump over time

[0016] 3. Large shrinkage rate

However, in practical application, it is found that the traditional polycarboxylate superplasticizer is very sensitive to the mud content in the aggregate. With the increase of the mud content in the aggregate, the dispersibility and slump retention of the polycarboxylate superplasticizer are obvious. Reduce, or even lose dispersion, in the environment where high-quality sand and gravel resources are increasingly scarce and almost exhausted, and under the background of environmental protection and sustainable development of concrete, the application of recycled aggregates and the implementation and promotion of recycled aggregate concrete have great potential must do

To realize the application and popularization of recycled concrete, the technical difficulties that urgently need to be solved are the problems of poor workability and large loss over time due to the high mud and powder content of recycled aggregates. Slump agent, is an urgent problem to be solved

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