【摘要】 通过混凝土经历10～-40、10～-80、10～-160℃等3种典型的超低温温度区间冻融循环作用试验,探讨不同的温度区间和冻融循环作用次数对混凝土峰值应变的影响。结果表明,经历不同温度区间冻融循环作用混凝土上下限温度时的混凝土峰值应变变化趋势不同。随冻融循环作用次数不断地增加,下限温度较低温度区间的混凝土峰值应变将不再增加而呈减小趋势。但各温度区间混凝土下限温度时的混凝土峰值应变因混凝土内孔隙水结冰均比其上限温度时大;不同温度区间的混凝土相对峰值应变差以及上下限温度时单次冻融软化指标和累积冻融软化指标均存在明显的差异且变化规律较为复杂。由试验结果拟合出混凝土相对峰值应变与超低温冻融循环作用的温度区间和次数间的关系式。所获得的这些结果可为LNG储罐类混凝土结构的设计和安全性能评估提供参考。更多还原

【Abstract】 Through the experiments of concrete experiencing the freeze-thaw cycle action with three typical ultralow temperature ranges of 10～-40 ℃,10～-80 ℃ and 10～-160 ℃,the effects of different temperature ranges and freeze-thaw cycles on concrete peak strain are discussed.The results show that the variation trends of peak strains of concrete undergoing freeze-thaw cycle action with different temperature ranges are different at upper and lower limit temperatures.With the further increase in freeze-thaw cycles,the peak strain of concrete experiencing action from the temperature range of which the lower limit temperature is lower will not increase but decrease.However,the peak strain of concrete at lower limit temperature for each temperature range is larger than that at upper limit temperature due to freezing of pore water in concrete.The concrete relative peak strain difference,and the single freeze-thaw softening index and the cumulative freeze-thaw softening index of concrete at upper and lower limit temperatures for different temperature ranges have obvious differences and the variation regularities are also more complex.The relationship between the relative peak strain of concrete and the factors of temperature range and freeze-thaw action cycles under ultralow temperature is also fitted based on the test results.These results can provide a reference for the design and safety performance evaluation of the concrete structures such as LNG storage tanks and so on.更多还原