EFFECT OF THERMAL CYCLES ON COMPRESSIVE STRENGTH OF HIGH STRENGTH CONCRETE (M90) COMPARED TO NORMAL STRENGTH CONCRETE (M 30)

摘要

With an increased usage of high strength concrete (HSC) in general structural construction and its application in power, nuclear and oil industries where structures are subjected to elevated temperatures and in the event of accidental fires, it is essential to investigate its behaviour. There is a serious lack of fire test data for HSC subjected to thermal cycles and hence it is important to study the mechanical properties of HSC compared to normal strength concrete. This paper presents the study of residual compressive strength and weight loss of high strength concrete compared to normal strength concrete of age 28 days subjected to thermal cycles namely 1, 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 apart from control concrete. Specimens were exposed to temperatures from 100 to 400°C for 8 hours exposure duration and subsequent air cooling for the remaining period of day. Therefore, one thermal cycle consists of 8 hours heating and 16 hours cooling. The results obtained can be useful as guidelines for fire resistant design of the structures subjected to heating and cooling cycles at elevated temperatures.