Study on fire performance characteristics of steel reinforcement in RCC structures

Abstract

The mechanical properties of the materials tend to change when they are subjected to fire. In this article, the effect of fire on the steel reinforcing bar is intended to enhance the understanding of how the rebar reacts as it is heated. In this article, the mechanical properties of steel rebar after exposure to varying elevated temperatures are analyzed in an experimental study on steel rebar. Fe500 steel bar with a diameter of 12 mm was used in this study. Here we used a total of 14 numbers of specimens, of which 7 are of steel rebar, which are embedded into cement mortar with a 25mm cover, and the other 7 are of rebar specimens of length 300mm, which are exposed to 300, 500, 600, 700, 900, and 1000 °C for 2 hours individually. After exposure to elevated temperatures in the muffle furnace, the specimens are cooled in two different cooling conditions. The first one is by cooling the samples at room temperature, and the second method is by sudden cooling. After cooling, the rebar is removed from the mortar samples. The tensile tests are conducted on all the rebar samples as per IS 1608:2005. The differences in elastic modulus, ultimate strength, and steel rebar elongation are determined, and other material behaviour requirements are also determined. All the results are compared and studied according to the temperature range exposed by the samples.