基于声发射技术的再生混凝土梁受弯过程的损伤特性研究

Acoustic emission characteristics of recycled concrete beams with different substitution rates during bending

基于声发射技术对不同再生粗骨料取代率的再生混凝土梁进行四点加载试验,根据试验中所得到的声发射事件数、声发射能量释放值、声发射累计事件数及累计能量释放值等参数建立再生混凝土梁的损伤模型,基于构建的损伤模型解释了声发射信号和再生混凝土梁损伤之间的关系,进一步的探究再生混凝土梁受弯破坏的损伤特性。结果表明:再生混凝土的声发射特性与普通混凝土总体趋势相似,再生混凝土的极限承载力随着再生粗骨料取代率的增加呈现出先增大后减小的现象;再生混凝土声发射特性能有效的反映混凝土的损伤程度,随着再生粗骨料取代率的增大,声发射事件数及能量释放在前期损伤积累过程中越大,梁的损伤变量D先减小后增大;基于AE累计事件数与应力的关系,建立再生混凝土声发射损伤演化模型,可以较好的表征再生混凝土梁受弯破坏的损伤演化规律。

In order to study the damage characteristics of recycled concrete beams,four-point bending tests were carried out on recycled concrete beams with different replacement rates of recycled aggregates based on acoustic emission technology.The damage model of the recycled concrete beam was established by the parameters of the number of acoustic emission events,the acoustic emission energy release value,the cumulative number of acoustic emission events and the cumulative energy release value obtained in the experiment.The acoustic emission parameters and the recycled concrete beam damage were explained based on the damage model.The results show that the AE characteristics of recycled concrete were similar to the general trend of ordinary concrete.The ultimate load of recycled concrete increased first and then decreased with the increase of the replacement rate of recycled coarse aggregate.The acoustic emission characteristics of recycled concrete effectively reflect the damage degree of concrete.With the increased of the replacement rate of regenerated coarse aggregate,the number of acoustic emission events and the release of energy in the process of pre-injury accumulation were larger.The damage variable D of the beam was first reduced and then increased.Based on the relationship between the number of AE cumulative events and the stress,the acoustic emission damage of recycled concrete is established.The evolution model can better characterize the damage evolution of recycled concrete beams subjected to bending failure.