中文摘要：

测试了水胶比为0．35，矿渣掺量为30％，50％和80％及粉煤灰掺量为30％和50％的混凝土在应力水平S≥0．80时的抗弯疲劳寿命，分别采用热分析法和压汞法测试了胶凝材料组成、水胶比与相应混凝土配合比相同的硬化浆体的非蒸发水量和孔隙率。测试结果显示：在应力水平S≥0．85时，混凝土的疲劳寿命随强度的提高而提高；在水胶比相同的情况下，非蒸发量随矿物掺合料掺量而变化，从而使基体孔隙率产生变化，影响混凝土强度和低周疲劳性能。基体孔隙率的降低，提高了基体密实性和基体抑制裂缝扩展的能力，从而提高了混凝土低周疲劳性能。

英文摘要：

numbers of cycle to failure of concrete with fixed ratio of water to binder of 0.35 and with 0%, 30%, 50%, 80% cement replaced by blast furnace slag, 30%, 50% cement replaced by fly ash were tested under high stress level （S ≥0.80） flexural cycle load. Non - evaporable water content and porosity of pastes with the same water to binder ratio and cement replacements to corresponding concrete mixtures were also tested by DSC - TG and Mercury Intrusion Porosimetry respectively. The results show that fatigue life increases with the increase of strength of concrete when stress level S≥ 0.85. The non - evaporable water content depends on the cement replacement levels when with a fixed water to binder ratio, hence influence porosity, ship between porosity and low- cycle fatigue behavior reducing the porosity of the matrix strength and low - cycle fatigue behavior of concrete. Relationindicates that low-cycle fatigue behavior can be improved by