C60混凝土高温后低周循环受压疲劳性能研究.

To study the relationship among the temperature levels to which the high strength concrete is subjected, the time the high strength concrete is heated and the low cyclic compressive fatigue damage of the high strength concrete, fatigue tests were performed on C60 concrete under low cyclic compressive loading after temperatures of 200, 500, 800℃. Tests results show that the color of high strength concrete turns lighter after high temperature, and the structure of specimen is looser. The maximum longitudinal total strain of the high strength concrete after high temperature under low cyclic compressive loading is in accordance with the three-stage development law. Compared with the stress level, the effect of high temperature process on the fatigue strain of high strength concrete is more significant, especially the influence of heating temperature. Estimation formula of fatigue life was proposed based on the second stage of strain development. Fatigue deformation modulus ratio and relative residual strain were defined as damage variables, respectively. And the relationship models between the high temperature process and the fatigue damage were established. According to the damage model established by fatigue deformation modulus ratio, the fatigue life of high strength concrete was predicted. The calculation result has a good agreement with the test result. [ABSTRACT FROM AUTHOR]