不同低温工况下混凝土的受压强度研究

Study on Compressive Strength of Concrete Under Different Low Temperature Action Conditions

基于由常温(20℃)降至给定低温(-40、-80、-120、-160、-190℃)、经历低温再直接或以1℃/min匀速回至常温3种工况下的混凝土受压试验,研究了不同低温作用下混凝土的受压强度及其离散性。结果表明:随着低温温度的降低,混凝土的受压强度变化率高于常温时的受压强度变化率,且整体呈增大趋势,其离散性也明显变大;而经历低温再直接和以1℃/min匀速回至常温时混凝土的受压强度变化率相比常温时均有所提高,但与低温温度关联度较低,其离散性也均减小。

The compressive strength and its discreteness of concrete subjected to different low temperatures were discussed through compressive experiment of concrete under three temperature conditions:cooling to given low temperatures(-40,-80,-120,-160,-190℃)from room temperature,and returning to room temperature directly and at a rate of 1℃/min after experiencing given low temperatures.The results show that the change rate of compressive strength of concrete at low temperature is higher than that at room temperature without experiencing action from low temperature and generally increases with the decrease in the low temperature,and its discreteness increases obviously.Compared with the change rate of compressive strength of concrete at room temperature,the change rate of compressive strength of concrete for returning directly and at the rate of 1℃/min to room temperature from low temperatures still increases,but the correlation with the low temperature is low and the compressive strength discreteness is also reduced.