Residual properties of recycled concrete after exposure to high temperatures

This paper presents the results of an experimental study on the residual properties of recycled concrete after exposure to high temperatures. Three parameters were considered in this test: (a) high temperatures (i.e. 20, 200, 300, 400, 500, 600, 700 and 800°C); (b) recycled coarse aggregate replacement percentages (i.e. 0, 30, 50, 70 and 100%); (c) recycled coarse aggregate types (gravel and pebble). A total of 144 standard prism specimens (150 mm × 150 mm × 300 mm) of recycled concrete were prepared and subjected to different high temperatures for 1 h; after cooling down to ambient temperature, the following basic physical and mechanical properties were then tested and discussed: (a) surface change and mass loss ratio; (b) compressive strength; (c) compressive stress–strain curve; (d) elasticity modulus. Based on the mass loss ratio, a residual strength assessment method for recycled concrete after exposure to high temperatures was put forward.