超低温冻融循环后混凝土应力～应变全曲线试验研究

通过对21个混凝土棱柱体试件进行冻融循环后的应力~应变全曲线试验,分析比较了不同温度和冻融循环次数对混凝土应力~应变全曲线的影响。试验研究表明:(1)超低温冻融循环后混凝土峰值应力降低,峰值应变随冻融循环次数的增加而增大;(2)在相同冻融循环次数条件下,冻融温度越低,相应的下降段曲线下降越缓慢;(3)在其他条件相同的情况下,冻融循环次数是影响不同冻融温度之间差异是否明显的主要因素。通过非线性拟合得到了受超低温冻融循环作用的混凝土应力~应变理论曲线,研究成果可为混凝土材料非线性分析提供参考。

Experimental study on complete stress-strain curve of concrete after freeze-thaw cycles under extra-low temperatures

Based on the complete stress-strain curve test on 21 concrete prisms specimens after freeze-thaw cycles， the effects from various temperatures and freeze-thaw cycle numbers on the complete stress-strain curve of concrete are analyzed herein. The test result shows that:（1）the peak stress decreases， while the peak strain increases along with the increase of the freeze-thaw cycle numbers;（2）under the condition of the same freeze-thaw cycle numbers， the lower the freeze-thaw temperature is， the slower the decline of the corresponding falling section of the curve is to be;（3）in the case of that the other conditions are the same， the freeze-thaw cycle number is the main factor to affect whether the differences in-between various freeze-thaw temperatures are obvious.The theoretical stress-strain curve of the concrete under the effect of the freeze-thaw cycle at extra-low temperature is finally obtained through the relevant non-linear fitting， and then the study result can provide a reference for the non-linear analysis of the concrete materials.