Efficient separation of coarse aggregates and cement mortar in the recycled concrete by water jet demolition

Abstract

The disposal of construction wastes have become the current focus worldwide towards the sustainable development. The adhesion of the cement mortar onto the aggregates significantly impedes the properties of the recycled aggregate concrete. Towards improving the recyclability of construction wastes, this work presents a novel demolition technology using high-pressure abrasive water jet (HAWJ). The results showed that the micro-cracks on the fracture surfaces of the recycled concrete after HAWJ demolition mainly developed along the interfaces between the aggregates and the cement, thus resulting in the efficient separation of the coarse aggregates. The residual compressive strength of the recycled concrete could retain 71% after HAWJ demolition, demonstrating that the effect of HAWJ demolition was negligible. Therefore, it is reasonable to conclude that HAWJ demolition is a promising strategy to recycle the old buildings.