Recycling of demolished concrete

Abstract

This paper investigates the possibility of recycling of demolished concrete blocks made with brick aggregates as coarse aggregate. For this, demolished concrete blocks from 33 different sites were collected and crushed into coarse aggregates. As virgin aggregate, first class brick aggregates (normal brick aggregate) were investigated. About 350 concrete cylinders of diameter 150mm and height 300mm were made using normal and recycled brick aggregates with W/C= 0.45 and 0.55. Test items include slump, unit weight, compressive strength, tensile strength, Young’s modulus, and stress-strain curve. For W/C = 0.55, recycled brick aggregate concrete shows lower compressive strength compared to the normal brick aggregate concrete. The results are improved for W/C=0.45. The average strength of recycled brick aggregate concrete is found at 25.5 MPa (3700 psi) and 20.7 MPa (3000 psi) for W/C=0.45 and 0.55 respectively. The results indicate that recycled brick aggregates can be used for new construction works instead of normal brick aggregates.