Spalling of cover concrete is a major concern for concrete elements subjected to elevated temperature, which result in direct exposure of rebar to elevated temperature. An experimental study was conducted on thermo-mechanically treated (TMT) rebar, for studying the influence of various heating – cooling process like the one occurring during fire accidents in infrastructure. The parameters considered are temperatures ranging from 100°C, 200°C, 300°C, 400°C, 500°C, 600°C, 700°C and 800°C and two types of cooling regimes like air cooling and quench cooling. The duration of exposure was maintained as two hours at the desired temperature. The different cooling condition had no major alteration in residual strength, stiffness and ductility of reinforcement for temperature below 400°C. In the case of temperature above 400°C to 800 °C, the yield strength was decreasing for air cooled specimen when compared with the quench cooled specimens but the air cooled specimen showed better performance in the ductility of reinforcement than the quench cooled specimen.
M. K. Haridharan and Natarajan, C., “Experimental study on thermo-mechanically treated rebar subjected to various thermal cycles”, Materials Today: Proceedings, vol. 4, pp. 9685 - 9689, 2017.