Shear behavior of recycled aggregate concrete after exposure to high temperatures

• Increasing RCA content has minimal effect on the shear behavior.
• The shear behavior of RAC is significantly affected by high temperatures.
• Shear stress–strain relation of RAC exposed to high temperatures is suggested.

This paper studied the shear behavior of concrete with different levels of recycled coarse aggregate (i.e., 0%, 50% and 100%) after being subjected to different temperatures (i.e., 20 °C, 200 °C, 300 °C and 400 °C). Thirty-six beam specimens with uniform depth and varying width were designed to test their mechanical parameters including shear strength, peak shear strain, stress–strain curves and shear modulus. We analyze how these parameters are influenced by recycled coarse aggregate (RCA) content and by high temperature. We establish the shear stress–strain equations for RCA-embedded concrete after exposure to different temperatures. It is found that the aforementioned mechanical parameters are minimally influenced by the RCA content at ambient temperature (about 20 °C). After exposure to high temperatures, the RCA content affects the shear strength insignificantly but increases the peak strain slightly. As the temperature elevates, the residual shear strength and shear modulus decline rapidly whereas the peak strain increases linearly. Furthermore, the normalized shear stress–strain curves become more disperse with the increment of temperature.