Experimental study on behavior of normal strength concrete influenced by elevated temperatures

Concrete subject to elevated temperatures are directly affected by inner microstructure blending components. As a consequence, owing to high temperatures, the non-destructive test (Rebound Index) helps to evaluates the behavior of concrete. The paper focuses on behavior of normal strength concrete specimens exposed to high temperatures ranging from 200°C to 800°C with distinct cooling regimes (air cooled condition, hot condition) on M20, M30 and M40 concrete grades. It is observed that the compressive strength is approximately 9% lower in air-cooled condition than in hot condition for concrete subjected to 200 to 400°C temperature. Reduction of compressive strength correlates with reduction of concrete graph cube strength by rebound hammer in temperature range from 600°C to 800°C. The results revealed that, due to greater crack propagation at temperature range between 600 and 800°C, the higher percentage loss in strength for M40 grade concrete results in reduced rebound index values.