摘要
文章针对废弃混凝土再生砂资源属性复杂、基本性能差异性大导致其难以被高效利用的问题,提出了基于再生砂的残余浆体质量分数分类及评价再生砂的方法.对北京、合肥、桐城、广州、成都和重庆的再生砂进行基本性能测试,以再生砂的残余浆体质量分数ɑRCC为基础,综合利用再生砂的表观密度、压碎指标、再生胶砂需水量比和强度比指标将再生砂划分成Ⅰ类、Ⅱ类和Ⅲ类3个等级并与现行规范比较.结果表明:分别以再生砂的残余浆体质量分数αRCC≤ 15%、15%<αRCC ≤25%、αRCC>25%划分再生砂的类别,其对应的各项基本性能指标都满足现行规范的要求;以残余浆体质量分数为基础对再生砂进行更简便精细的分类及品质评价.该分类方法有利于再生砂的差异化高效利用.
Abstract
Aiming at the problem that recycled fine aggregate resource of waste concrete is difficult to be used efficiently due to its complex attribute and great difference in basic performance,this paper proposes a method to classify and evaluate recycled fine aggregate based on its residual cement paste content.The basic performance of recycled fine aggregate in Beijing,Hefei,Tongcheng,Guangzhou,Chengdu and Chongqing was tested.Based on the residual cement paste content ɑRCC of recycled fine aggregate,the recycled fine aggregate was divided into three grades,namely,Class Ⅰ,Class Ⅱ and Class m,by comprehensive utilization of the apparent density,crushing index,water demand ratio and strength ratio of recycled mortar,and compared with the current specifications.The results show that the recycled fine aggregate can be classified according to its residual cement paste content ɑRCC≤15%,15%<ɑRCC≤25%,ɑRCC>25%,respectively,and its corresponding basic performance indexes meet the requirements of current specifications.The recycled fine aggregate can be classified and eval-uated more simply and precisely based on the residual cement paste content.This classification meth-od is conducive to the differential and efficient utilization of recycled fine aggregate.