Recycled Concrete Using Crushed Construction Waste Bricks Subject to Elevated Temperatures

Abstract

The objectives of this paper are to find the compressive strength and ultrasonic pulse velocity (UPV) of recycled concrete with various percentages of natural fine aggregate replaced by Recycled brick fine aggregate (RBFA) as well as the residual strength and residual UPV of recycled concrete subjected to elevated temperatures. Experiment results showed that the compressive strength and UPV decreased as amount of RBFA in concrete increased, the long-term performance of compressive strength and UPV development increased as the RBFA content increased. The residual strength of recycled concrete increased slightly after heating to 300°C and the residual UPV of recycled concrete decreased gradually as the exposed temperature increased beyond 300°C. In the range of 580 -800°C, recycled concrete lost most of its original compressive strength and UPV. After subjected to the temperature of 800°C, compared to plain concrete, recycled concrete with 100% RBFA had a greater discount rate of compressive strength and UPV of the order of 5-15% and 6-10%. Regression analysis results revealed that the residual strength and residual UPV of recycled concrete had a high relevance after elevated temperatures exposure.