Application of recycled coarse aggregate by mixture concrete construction

Abstract

In Malaysia, construction industry generates a large amount of waste which will be disposed at landfill area. If this continues to occur, it will bring harm to the environment. This study is to reduce the disposal problems of concrete waste by transforming it to use as coarse aggregate for new concrete. Recycled coarse aggregate (RCA) is produced from concrete waste in form of concrete cubes gathered from laboratory at UniMAP. Numerous types of concrete cubes are used for the production of RCA. A study has been conducted to investigate the mechanical properties of RCA concrete in terms of compressive strength, water absorption, fire resistant property, depth of carbonation and microstructure. Comparison of RCA concrete with conventional concrete is made. The samples are cast in 150 × 150 × 150 mm mould and undergone curing process for 7 and 28 days before testing. Four major types of samples used are 0%, 20%, 50% and 100% of RCA content to study the influence of percentage of RCA replacement. Results showed that the RCA concrete has lower compressive strength but higher water absorption rate compare to conventional concrete. Analysis for depth of carbonation proved that RCA concrete was suitable to prevent corrosion to reinforcement bar in concrete. Meanwhile, fire resistant property considered to be on a par with conventional concrete. Microstructure analysis showed that the RCA concrete samples are more porous and covered with loose particles on the surface.