Properties of precast hollow concrete blocks using recycled concrete aggregates

The reuse of concrete as aggregate in new concrete mixes helps to reduce the expenses related to management of construction and demolition (C&D) waste, and to helps the environment by reducing the development rate of new quarries. This study has investigated the potentiality of using coarse recycled concrete aggregate in the manufacture of precast hollow concrete blocks. Four series of mixtures have been prepared by using coarse recycled concrete aggregates in replacement percentages of coarse natural aggregates (20%, 50%, 70%, 100%), and an ordinary mix made by natural aggregate as control. The purpose of this study is to investigate the effect of coarse recycled concrete aggregates on compressive strength, density and absorption of precast hollow concrete blocks. The results show that the performance of concrete blocks realized with coarse recycled concrete aggregates are comparable to those obtained with concrete blocks using exclusively natural aggregates. Furthermore there is no additional cost to the routine precast hollow concrete blocks production.