The experimental studies on the mechanical properties of concrete under action of different temperatures and different heating time were conducted by hydraulic servo testing system.The influence of the different temperatures

different heating time on compressive strength

elastic modulus

stress-strain relation of concrete was analyzed.The test results show that the mechanical properties of concrete under action of high temperature deteriorate with the rise of temperature

and the compressive strength and elastic modulus decrease with the rise of heating temperature and the extension of heating time

while the peak strain increases gradually.And the regularity and mechanism of change in compressive strength

elastic modulus

stress-strain relation of concrete affected by different temperature and different heating time were analyzed in this paper.And regression formulas of the compressive strength and elastic modulus changes with different temperature and different heating time were obtained.The regression curve and test curve were compared

the results show that the regression curve can be well used to simulate test curve.