含砖块水泥稳定建筑垃圾基层耐久性研究

Study on durability of cement-stabilized construction waste base containing bricks

为了提高建筑垃圾中砖块的有效利用率,明确再生骨料中砖块含量对水泥稳定建筑垃圾的影响,针对再生骨料中不同砖块含量(质量分数分别为0,10%,20%,30%)的水泥稳定建筑垃圾基层,进行抗冻性试验、干缩试验、温缩试验、SEM扫描电镜分析,从宏观和微观2个角度研究砖块含量对水泥稳定建筑垃圾基层耐久性的影响。研究结果表明:随着砖块含量升高,水泥稳定建筑垃圾基层的冻融循环残留强度比降低、质量损失率增高;干缩失水率、干缩应变、干缩量都相应增加;温缩系数、温缩应变则均是先减小后增大,平均温缩系数和累计温缩应变均升高;再生骨料中砖块含量的增加导致水稳建筑垃圾基层的孔隙率增大,水化反应产物结构疏松使耐久性发生劣化。研究结果拓宽了含砖块建筑垃圾再生利用的有效途径,并为含砖块建筑垃圾再生后用做水泥稳定基层材料提供了理论支持。

In order to improve the effective utilization rate of bricks in construction waste and clarify the influence of brick content in recycled aggregate on cement stabilized construction waste,frost-resistance test,dry-shrinkage test,temperature-shrinkage test and scanning electron microscope(SEM) analysis were conducted for cement stabilized construction waste base course with different brick contents(mass percentage of 0,10%,20%,30%,respectively) in recycled aggregate.The influence of brick content on the durability of cement stabilized construction waste base was studied from both macro and micro perspectives.The results show that:with the increase of brick content,the freeze-thaw cycle residual strength ratio of cement stabilized construction waste base decreases and the mass loss rate increases;The drying-shrinkage loss rate,dry-shrinkage strain and dry-shrinkage amount are all increased correspondingly;The temperature-shrinkage coefficient and the temperature-shrinkage strain decrease first and then increase,and the average temperature-shrinkage coefficient and the accumulated temperature-shrinkage strain both increase;The increase of brick content in recycled aggregate leads to the increase of porosity of cement stabilized construction waste base,and the structural looseness of hydration reaction products leads to deterioration of durability.The research results broaden the effective way of recycling construction waste containing bricks,and provide theoretical support for the use of recycled construction waste containing bricks as cement stabilized based material.