水胶比对再生骨料透水混凝土性能的影响分析

Influence of Water-binder Ratio on Recycled Aggregate Pervious Concrete

利用再生骨料制备透水混凝土,设计了以水泥为胶凝材料的变水胶比(0.24~0.36,计5个梯度)与以水胶比0.30为基准的定水胶比(掺粉煤灰5%~20%,计4个梯度)两个系列共9组试验配合比,研究了水胶比、骨灰比对再生骨料透水混凝土性能的影响规律。在此基础上,协同熵值法和灰色关联分析法,对配合比方案进行综合评价与分析,确定最佳水胶比。结果表明,变水胶比条件下,胶水比与再生骨料透水混凝土抗压强度呈线性正相关关系,水胶比与孔隙率、渗透系数呈指数变化规律;骨灰比与抗压强度呈线性反相关关系,与孔隙率、渗透系数呈指数变化规律;经综合评价分析,水胶比为0.30的配合比最优。定水胶比条件下,掺入粉煤灰会降低再生骨料透水混凝土强度,但能增加渗透性能,考虑综合性能时建议粉煤灰掺量为5%。

The recycled aggregate pervious concrete(RAPC)is prepared by using recycled aggregates.Two series of 9 groups of experimental mix ratios are designed for the RAPC,including variable water-binder ratio(w/b)series with cement as cementitious material(0.24~0.36,total 5 gradients)and fixed w/b series(w/b is 0.30)(5%~20%fly ash replacement,total 4 gradients).The influence of w/b and aggregate-binder ratio on the properties of RAPC are studied.On this basis,the entropy method and gray relational analysis method are used to evaluate mix ratios comprehensively to determine the best w/b.The results show that,(a)there is a linear positive correlation between the binder-water ratio and the compressive strength of RAPC under variable w/b,and the w/b is exponential with void content and permeability coefficient;and(b)the aggregate-binder ratio shows a linear inverse correlation with compressive strength and is exponential with void content and permeability coefficient respectively.According to comprehensive evaluation,the best w/b is 0.30.Under the condition of fixed w/b,the incorporation of fly ash will reduce the strength of RAPC,but increase permeability.Considering the comprehensive performance of RAPC,it is suggested that the amount of fly ash is 5%.