EXPERIMENTAL RESEARCH ON MECHANICAL PROPERTIES OF HRBF500 AFTER HIGH TEMPERATURES

The mechanical properties of hot rolled bars of fine grains(HRBF500) after high temperatures were studied experimentally.Eleven groups(33 specimens)were tested after temperatures of 20,100,200,300,400,500,600,700,800,900,and 1 000 ℃,respectively.The variation of yield strength,ultimate strength,elastic modulus,elongation and tensile stress-strain relationship of the HRBF500 at elevated temperatures were investigated and discussed.The results show that the variation of the mechanical property of HRBF500 is not obvious when the highest temperature the reinforcing bar reached is less than 500 ℃;while the stress-strain curves of reinforcing bar become more ductile and the mechanical property indexes of the reinforcing bar degenerate gradually when the highest temperature is more than 500 ℃.Based on the results of the experiment,the calculation formulas for yield strength,ultimate strength,elastic modulus after high temperatures are proposed.All can be served as basic data for analysis of fire resistance and after-fire damage evaluation of structures with hot rolled bars of fine grains(HRBF500).