利用再生骨料制备透水混凝土试验研究

Experimental research on pervious concrete with recycled aggregate

利用再生骨料制备透水混凝土,具有良好的生态效应和社会效益。本试验采用附加水量法,按不同净浆水灰比及净浆对骨料空隙的填隙系数配制一系列试样,观察无砂透水混凝土试样的积浆情况并测试抗压强度。试验发现,净浆水灰比偏大时易造成透水混凝土积浆堵孔,水灰比偏小时则成型效果差,两种情况均对强度不利。透水混凝土属于骨架空隙结构,强度与灰水比的关系不符合鲍罗米公式。在不积浆条件下,净浆强度与流动性矛盾达到平衡时的水灰比为最佳水灰比(约0.30),此时试样不易积浆且强度达到最高(10.2MPa)。透水平衡时,每平方米地面透水流量将近0.3m^3/min,将在海绵城市系统中发挥很好的调蓄作用。

The application of recycled aggregate in preparing pervious concrete has great ecological effects and social benefits.The experiment was performed in method of additional water content.In the experiment,a series of no-fines pervious concrete samples with recycled aggregate were prepared in various water-to-cement ratio of paste(W_0/C) and different paste-to-voids ratio(k) to observe the situation of paste deposition and test their compressive strength.The results reveal that higher W_0/C brings possibility of paste deposition and blocks up pores inside pervious concrete,however,lower W_0/C causes bad formation of concrete.Lower strength appears in both cases.Because pervious concrete belongs to skeleton-gap structure,the relation between strength and cement-to-water ratio(C/W_0) doesn't comply with Bolomey equation.In condition of none paste deposition,there exists optimal W_0/C(approximate 0.30) when discrepancy between strength and fluidity is balanced.In such circumstance,the strength of pervious concrete reaches maximum(10.2MPa) without paste deposition.The measured regime discharge through each square meter was near upon 0.3m^3/min.The pervious concrete will play an important role in a ‘sponge city' to deal with rainwater.