摘要
将混凝土的粗、细骨料用MRA 100%取代配置全再生混凝土.以 3 种水灰比和 3 种浆骨比为变量,设计试验配合比.对新拌混凝土进行坍落度试验,对养护龄期为 3d、7d、14d、28d和56d的试件进行抗压强度试验.结果表明,二次搅拌工艺、水灰比和浆骨比对坍落度的影响程度依次增大;MRA全再生混凝土的强度发展较为缓慢,采用降低水灰比、提高浆骨比和二次搅拌的方式能有效提高抗压强度.
Abstract
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.
基金项目
河南省教育厅高等学校重点科研项目(24B560025)
许昌学院大学生创新创业训练计划(2023)()
NETL
NSTL
万方数据