Summary of research on pretreatment methods of recycled aggregate

Abstract

The recycled aggregate obtained by simple crushing and screening of waste concrete has a rough surface and many protruding edges and corners, and most of the aggregate surface is attached with old mortar, when directly used as aggregate in concrete, the water demand is large, the concrete strength and elastic modulus are low, and the durability is poor. Therefore, proper treatment of recycled aggregate is required.This article summarizes the research status of the pretreatment methods of mechanical strengthening, heating grinding, solution impregnation, cement slurry impregnation, carbonization treatment, nano-modification, microbial modification and water cleaning etc., and simply analyzes the advantages and disadvantages of various treatment methods, which provide a reference for the research of recycled aggregate processing methods.

The Historical Different Meanings of Chinese Communist Party’s ‘The Party Commands Gun’ Under Mao Zedong and Deng Xiaoping

“…Liu Bocheng, Xu Xiangqian, Nie Rongzhen and so on, were suspects. Mao decided that old commanders and generals could hold military positions, but they were not allowed to lead troops (Zhang 1976).…”