Experimental Study on Preparation of Fully Recycled Concrete from Brick Slag
The recycled aggregate made by crushing and processing after the demolition of brick-concrete buildings contains brick slag,crushed mortar,waste concrete and crushed porcelain pieces,referred to as mixed recycled aggregate(MRA).The coarse and fine aggregates of the concrete were replaced with MRA 100%and fully recycled concrete was configured.With 3 kinds of water-cement ratios and 3 kinds of paste-aggregate ratios as variables,a total of 9 groups of test mix were designed.Each group of mix ratio was prepared by the secondary mixing process and the ordinary mixing process,respectively.Slump test was carried out on the newly mixed concrete,and compressive strength test was carried out on the specimens with curing ages of 3 d,7 d,14 d,28 d and 56 d.The results show that the influence of secondary mixing process,water-cement ratio and paste-aggregate ratio on slump increases sequentially.The strength development of MRA fully recycled concrete is relatively slow,and the compressive strength can be improved effectively by secondary mixing,reducing water-cement ratio and increasing the paste-aggregate ratio.Due to the performance limitations of high porosity,high water absorption and high pressure crushing value of MRA,it is necessary to consider both water-cement ratio and pulp to bone ratio to meet the design strength level.
mixed recycled aggregatefully recycled concretemix processwater-cement ratiopaste-aggregate ratio
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