为提高再生细骨料(regenerate fine aggregates,RFA)的回收使用率,本研究采用一种含砖RFA进行全再生细骨料混凝土(fully recycled fine aggregate concrete,FRFAC)的试验制备.设计吸水率试验拟合公式计算RFA的主要组成及含量;通过设计正交试验研究水料比、减水剂和RFA粒径级配对不同养护天数下FRFAC的强度与热工性能的影响.研究结果表明,该RFA中主要包含废砖、废混凝土和泥块,其含量分别为13.58%、52.98%和33.44%,泥块含量较多,所以在制备前需对RFA进行筛分处理,该RFA平均吸水率较大,所以需采用饱和面干法进行预处理;对FRFAC强度影响最大的是RFA粒径级配,其次是水料比和减水剂,强度随着养护天数呈缓慢上升趋势;FRFAC的导热系数低,通过抗压导热交互分析得到配比最优方案为A3B3C2,制备的FRFAC强度达到25.8 MPa,导热系数为0.4636 W/(m·K),可用于建筑工程中.
Preparation and Performance Test Study of Fully Recycled Fine Aggregate Concrete
In order to improve the recycling rate of regenerate fine aggregates(RFA),a brick-containing RFA is used for the experimental preparation of fully recycled fine aggregate concrete(FRFAC).The water absorption test fitting formula is designed to calculate the main composition and content of RFA.Orthogonal experiments are designed to study the effects of water-to-material ratio,superplasticizer and RFA particle size class pairing on the strength and thermal properties of FRFAC under different curing days.The results show that the RFA mainly contains waste bricks,waste concrete and mud blocks,and their contents are 13.58%,52.98%and 33.44%,respectively;the mud content is large,so the RFA needs to be screened before preparation;the average water absorption rate of the RFA is large,so it needs to be pretreated by saturated surface dry method.The particle size gradation of RFA has the greatest effect on the strength of FRFAC,followed by the water-to-material ratio and superplasticizer,and the strength shows a slow upward trend with the number of days of curing.The thermal conductivity of FRFAC is low,and the optimal ratio scheme is A3B3C2 obtained through the interaction analysis of compressive and thermal conductivity,and the prepared FRFAC has a strength of 25.8 MPa and a thermal conductivity of 0.4636W/(m·K),which can be used in construction projects.
construction wasterecycled concretewater absorption experimentorthogonal testregenerate fine aggregates
万方数据
维普
