Mechanical behavior of three generations of 100% repeated recycled coarse aggregate concrete

Abstract

Demolished concrete generates significant volume of construction and demolition (C&D) waste worldwide that has huge potentials for concrete coarse aggregate. This study discusses the use of recycled coarse aggregate in concrete in a repeated fashion, and investigates the fresh and hardened properties of this green concrete type. Three different generations (1st, 2nd and 3rd) of repeated recycled concrete were produced using 100% recycled coarse aggregate (RCA) as a replacement of natural coarse aggregate where RCA was recycled 3 times over its life span. i.e. the 3rd generation recycled concrete was made with RCA, which was produced after 3 repeated casting of recycled concrete with 100% RCA and then demolishing the hardened concrete. The results show that the repeated recycled concrete experienced slightly lower compressive strength than the control concrete; however, all mixes successfully achieved their target strength at 56th day expect the 3rd generation concrete. Another interesting finding of this study shows that even the 3rd generation concrete could surpass the target strength by at least 25% while considering long term strength gain. The stress–strain curves of repeated recycled concrete are also presented and discussed.