Influence of grade of parent concrete on recycled aggregate concrete made with pozzolanic materials

Abstract

Reducing, recycling and reuse is becoming a world renowned proverb nowadays. The waste from construction industry is increasing day by day. Two major kinds of waste produced from construction industry are concrete waste and brick waste. The concrete waste produced from different buildings will have different strengths. The purpose of this study is to look into the reuse of concrete waste collected from various buildings in the production of recycled aggregate concrete (RAC). RAC 30 is produced by replacing the natural aggregates with recycled aggregates (RA) derived from granite aggregate concretes GAC30 (RA30), GAC35 (RA35) and GAC40 (RA40) grades of parent concrete. In order to produce sustainable concrete, pozzolanic materials such as fly ash (FA) and silica fume (SF) are used in conjunction with cement at a rate of 20% and 10% respectively, in addition to cement. The influence of strength of different grades of parent concrete (GAC) on production of RAC of grade 30 (RAC 30) is studied. The experimental results show that RA derived from parent concrete grades GAC30 (RA 30) can be substituted fully in place of normal aggregate. The use of 20% FA and 10% SF in place of cement also contributed to the enhanced compressive strength, leading to sustainable concrete in field of architectural construction.