通过给定配合比混凝土的低温受压试验,考察混凝土在不同低温作用工况下的力学性能变化规律。结果表明,不同低温下混凝土立方体试件的破坏形态相似,但其破坏随温度的降低变得越来越突然。混凝土的低温受压强度经历损伤阶段、快速增长阶段和平稳波动阶段。混凝土低温受压强度在约-20℃时达到极小值,其降幅达常温的16.5%;在约-100℃时达到极大值,其增幅达常温的57.5%。根据试验结果和已有的研究结果建议了用于工程设计的混凝土低温受压强度相对增量计算公式。
Through experiments of the given mix proportion concrete exposed to different cryogenic temperatures, the compressive mechanical properties were discussed. From the test results it can be shown that the failure modes of the cube concrete specimens at various cryogenic temperatures are similar, but the specimen failure becomes sudden with decrease in temperature. The compressive strength of concrete at cryogenic temperature experiences three phases: damage stage, rapid growth stage and stationary fluctuation stage. The compressive strength of concrete reaches a minimum value at about -20℃ with a drop of 16. 5% relative to that at normal temperature and a maximum value at about - 100℃ with an increase of 57.5% relative to that at normal temperature respectively. Based on the experiment and the existing results, a relative increment formula for the compressive strength of concrete applied to the engineering design of concrete structures at cryogenic temperature is also provided.