早龄期荷载及低温作用下的混凝土声发射特征试验研究*

井壁混凝土由于施工与环境特殊性导致其裂缝扩展情况异常,本文通过对不同早龄期荷载、低温条件下混凝土轴压破坏过程的声发射检测,分析井壁施工环境对混凝土内部裂缝产生、发展的影响。研究表明,早龄期荷载、低温单独作用时,与标养混凝土主要差异在轴压过程中的声发射初始阶段,对混凝土内部的原有收缩裂缝有所影响。当两者耦合作用时,早龄期荷载影响比低温作用显著,并且在早龄期荷载较大时会出现声发射信号"倒置"现象。

Experimental study on acoustic emission characteristics in concrete material influenced by early-age loads and low temperature

The borehole wall concrete cracks develop abnormally because of the unusual circumstances of construction and environment. In order to investigate the influences of the construction circumstances on borehole wall concrete damage, uniaxial compression acoustic emission tests were carried out on the concrete specimens for different early-age loads and low temperature. The results show that under the circumstance of early-age loads or low temperature, the main difference between specimens and normal concrete is in the first stage during the uniaxial compression tests, and the shrinkage cracks are affected. When early-age loads and low temperature working together, the influences on concrete damage by early-age loads is greater, and the acoustic emission(AE) signals present inversion when the early-age loads are big enough.