Utilization of Recycled Concrete Aggregate for High Performance alkali Activated Concrete: Towards a Sustainable Building Solution

Abstract

Abstract The purpose of this study is to prepare environmentally friendly and highly sustainable concrete for an ever-increasing demand of concrete in the construction industry. In the study both natural course and fine aggregates were partially replaced by recycled concrete aggregate from construction and demolition wastes. High performance alkali activated concrete was prepared by utilizing pozzolanic industrial wastes as a binder which fully replaced cement powder. High volume of fly ash with 30%, 40% and 50% replacement of slag was used as a main binder. NaOH and Na2Si03 with an alkali modulus of 0.6 were used as an alkali activator solution. The findings of this research revealed that alkali activated recycled aggregate concrete have competitive engineering properties with respect to cement concrete with natural aggregate. The UPV and thermal conductivity test results were found to be 4302 m/s and 1.425 W- m-l-K-1 respectively. The results of this study will pave the way towards the better practice of sustainable concrete construction by replacing the cement and natural aggregate in one concrete mix.