Residual mechanical properties of recycled aggregate concrete at elevated temperatures

This research examines the residual mechanical properties of normal and recycled aggregate concrete when subjected to elevated temperatures. The concrete specimens containing recycled aggregate (0%, 50%, 75%, and 100%) were exposed to different temperatures (25, 200, 400, and 600 & DEG;C) in a muffle furnace at a heating rate of 10 & DEG;C/min. The variations in flexural strength, compressive strength, and density were then tested according to ASTM standards. Findings from this investigation indicate that the degradation in the mechanical strength of concrete does not seem to be significantly affected by the increase in the percentage of recycled aggregates. However, a significant and linear decrease in the density was observed at 400 & DEG;C with an increase in the percentage of recycled aggregates. The degradation of the compressive and flexural strengths of recycled aggregate concrete with increasing temperatures obtained from the experimental analysis was compared with the analytical predictions provided by Eurocode 2. Moreover, simplified equations have been proposed to estimate the degradation of the mechanical properties of recycled aggregate concrete at higher temperatures. The incorporation of recycled aggregates into concrete resulted in satisfactory residual performance.

Automated summary

This research investigated the residual mechanical properties of normal and recycled aggregate concrete under elevated temperatures. Concrete specimens with different percentages of recycled aggregates (0%, 50%, 75%, and 100%) were exposed to various temperatures (25°C, 200°C, 400°C, and 600°C) in a muffle furnace. The study found that the increase in recycled aggregate content did not have a significant effect on the mechanical strength degradation of concrete. However, a linear decrease in density was observed at 400°C with increasing percentage of recycled aggregates. Simplified equations were proposed to estimate the degradation of mechanical properties of recycled aggregate concrete at higher temperatures, and the incorporation of recycled aggregates resulted in satisfactory residual performance.