Experimental study on the time-dependent dynamic mechanical behaviour of C60 concrete under high-temperatures

摘要

To study the dynamic mechanical behavior of C 60 concrete at high temperatures,impact tests under different steady-state temperature fields( 100,200,300,400 and 500 ℃) were conducted under a variety of durations at the corresponding constant high temperature,namely 0,30,60,90 and 120 min,employing split H opkinson pressure bar( SH PB) system. In addition,the impact tests were also conducted on the specimens cooled fromthe high temperature to the roomtemperature and the specimen under roomtemperature. Fromthe analysis,it is found that C 60 concrete has a time-dependent behavior under hightemperature environment. U nder 100,200,300,400 and 500 ℃ steady-state temperature fields respectively,as the duration at the corresponding constant high temperature increases,the dynamic compressive strength and the elastic modulus decrease but the peak strain generally ascends. After cooling to the roomtemperature,the dynamic compressive strength and the elastic modulus descend as well,but the peak strain increases first and then decreases slightly,when the duration increases. For specimens under and cooled fromthe high-temperature,as the temperature increases,the dynamic compressive strength and the peak strain raise first and then reduce gradually,and the dynamic compressive strength of specimen under high temperature is higher than that of the specimen cooled fromthe same high temperature.