废弃混凝土掺合型再生混凝土的力学性能

Mechanical Properties of Waste Concrete-Participated Recycled Concrete

针对当前再生混凝土工程应用所面临的再生骨料生产成本高昂和废弃混凝土利用率偏低的问题，提出将废弃混凝土经适当破碎和湿水后直接与新拌混凝土混合拌制工程用混凝土，制得一种新型的再生混凝土材料---废弃混凝土掺合型再生混凝土。拌制该再生混凝土所用废弃混凝土块的最大粒径可达50～80 mm，扩大了废弃混凝土在降低生产成本方面的优势，同时提高了废弃混凝土的利用率。对150、300 mm模数废弃混凝土掺合型再生混凝土试件以及废弃混凝土掺合型再生混凝土板的力学性能进行了研究。结果表明：废弃混凝土掺合型再生混凝土具有良好的力学性能，即使在废料掺量达到30％～40％时，其抗压强度、抗拉强度和弹性模量仍很接近相应强度等级的普通混凝土；废弃混凝土掺合型再生混凝土板的冲切承载力及破坏特征与普通混凝土板相近。

In order to reduce the production cost of recycled aggregate and improve the utilization rate of waste con-crete in common engineering application of recycled concrete,a new type of recycled concrete material named waste concrete-participated recycled concrete was prepared by straightly blending wet and broken waste concrete block with fresh concrete.The maximum size of waste concrete block for blending is up to 50~80 mm,which may expand the superiority of waste concrete in reducing the production cost and improving its utilization rate.Then,mechani-cal behavior studies were conducted for the 150 or 300 mm module specimens and the slabs of waste concrete-partici-pated recycled concrete.The results show that,even when the participation rate of waste concrete reaches 30%~40%,the compressive strength,tensile strength and elastic modulus of the prepared recycled concrete are very close to those of common concrete in the same strength grade,which means that the recycled concrete possesses ideal mechanical properties.Moreover,it is also found that both the punching bearing capacity and the failure cha-racteristics of the recycled concrete slabs are very close to those of common concrete slabs.