再生粗骨料的微观特征及基本性能研究

Research on Microscopic Features and Basic Properties of Recycled Coarse Aggregate

作为建筑垃圾主要组成之一的废弃混凝土,可以通过回收处理变为再生混凝土骨料,部分或全部代替天然骨料而再次应用到建筑工程中。通过扫描电子显微技术,对破碎后的骨料表面的微观状态进行了观察分析,得到了再生骨料表观特征以及微裂缝分布情况。同时依照JGJ 52-2006《普通混凝土用砂、石质量及检验方法标准》对再生粗骨料进行了基本性能测试,并与天然粗骨料的基本性能进行对比。通过实验,得出了再生粗骨料具有表观密度小、吸水率与含水率高、压碎指标值较高、针片状含量小的特点。还对实验结果进行了分析,为制备再生混凝土提供了依据。

As the main part of construction waste, concrete demolition waste can be reused as recycled coarse aggregates to partially or fully replace natural aggregates in the production of structural concrete. To evaluate the viability of this process, the surface characteristics of recycled coarse aggregates and the distribution of microcrack were investigated by means of environmental scanning electron microscope（ESEM）. Meanwhile, in accordance with the ＂Ordinary concrete sand standards for the quality and examination methods＂（JGJ 52--2006）,a series of tests of the recycled coarse aggregates were implemented in order to find its basic mechanical properties. Compared to natural aggregate, the features of recycled aggregate show smaller apparent density, higher water absorption, moisture content and crushed index value, smaller needles content. In addition, the test results are analyzed, providing the basis for the preparation of recycled concrete.