再生骨料基层透水铺装堵塞与过滤特性试验研究

Experimental study on the clogging and filtration characteristics of permeable pavement of recycled aggregate base layer

为了研究利用混凝土再生骨料作为透水铺装(permeable pavement,PP)基层的可行性,分别以天然砂石或水泥混凝土再生骨料为基层、以混凝土透水砖或陶瓷透水砖为面层,开展了一维渗滤柱试验,测试透水铺装渗透性及渗滤液特征。试验结果显示:在人工配置的固体悬浮物(suspended solids,SS)溶液模拟降雨径流作用下,透水铺装各深度渗透系数均按照指数规律衰减,指数衰减系数随深度的增加线性减小;堵塞主要由悬浮物粒径>10μm的颗粒导致,主要发生在透水铺装顶部20 cm范围。另一方面,各透水铺装对雨水径流均有良好的过滤效果;与天然砂石相比,混凝土再生骨料吸收水中悬浮物的能力略强,渗滤液pH值略高。结果表明,总体上再生骨料与天然砂石的渗透性相近,再生骨料基层对悬浮物的过滤效果优于天然砂石,说明透水铺装基层材料使用混凝土再生骨料取代天然砂石是可行的。

A one-dimensional percolation column test was carried out to test the permeability of the permeable pavement and the characteristics of the leachate in order to study the feasibility of the utilization of recycled concrete aggregate as the base layer of the permeable pavement(PP).In the tests,natural sand or cement concrete recycled aggregate were employed as the base layer,while concrete permeable brick or ceramic permeable brick were used as the surface layer.The test results show that under the artificially configured solution of suspended solids(SS)to simulate rainfall and runoff,the permeability coefficient of each depth of the permeable pavement is attenuated exponentially,and the exponential attenuation coefficient decreases linearly with the increase of depth;The blockage is mainly caused by suspended particles with particle size greater than 10μm,which occurs within a range of 20 cm at the top of the permeable pavement.On the other hand,each permeable pavement has a good filtering effect on rainwater runoff;compared with natural sand and gravel,the recycled aggregate concrete has a slightly stronger ability to absorb suspended solids in the water,and the pH value of the leachate is slightly higher.The results show that,on the whole,the permeability of reclaimed aggregate is similar to that of natural sand and gravel,and the filtration effect of reclaimed aggregate base is better than that of natural sand,indicating a good feasibility for the application of reclaimed aggregate concrete instead of natural sand for pervious pavement base material.