A method of improving the quality of waste concrete recycled aggregate by using sodium hydroxide alkali solution

Abstract

The invention discloses a method for improving the quality of waste concrete recycled aggregate by employing a sodium hydroxide alkaline solution. The waste concrete recycled aggregate of which the particle size is 5-20mm is soaked by using a NaOH water solution of which the mass concentration is 8-12%; and the soaking and repairing time is 28-32 days. The method has the beneficial effects that the water absorption rate of the recycled aggregate is reduced, the apparent density is improved, the quality of the recycled aggregate is greatly improved, and the water absorption rate and apparent density of the recycled concrete coarse aggregate repaired by the NaOH water solution reach the GB / T25177-2010 concrete recycled aggregate III-grade standard. The waste concrete recycled aggregate can be used for preparing new concrete, and the problem of disposal of waste concrete construction wastes is solved.

Description

technical field [0001] The invention belongs to the field of recycling of construction waste, and in particular relates to a method for improving the quality of recycled aggregate of waste concrete by using a sodium hydroxide alkali solution. Background technique [0002] At present, construction concrete waste accounts for about 40% of construction waste, and the amount is very large, but the amount that can be reused is very small. The main part of the waste concrete powder is sent to the landfill, and the landfill will not only occupy a large amount of land, but also pollute the soil and air. The ideal state of waste concrete recycling is to be able to prepare high-quality recycled aggregates. However, the current methods of processing waste concrete mainly include basic processes such as "crushing, screening and removing impurities". The prepared recycled aggregate contains cement stones, has high porosity, high water absorption, and low apparent density, which leads to...

AI Technical Summary

Problems solved by technology

However, the current methods of processing waste concrete mainly include basic processes such as "crushing, screening and removing impurities". The prepared recycled aggregate contains cement stones, has high porosity, high water absorption, and low apparent density, which leads to recycled concrete. The performance of the

At present, domestic researchers mostly use external materials of different properties (such as polymers, silicone waterproofing agents, cement with Kim powder, cement with first-grade fly ash, etc.) to impregnate, rinse, and dry recycled aggregates. Treatment, this method utilizes the cementitious characteristics of the external material itself to cover the surface of the recycled concrete. However, the reinforcement of the recycled aggregate by the above method is only reflected on the surface, and it is difficult to penetrate into the interior, and it is easy for the external material to cover the shell. Shedding, most additional materials also have the disadvantage of high cost

Images