碳化高温后再生混凝土受压声发射特性与损伤演化  

Acoustic emission characteristics and damage evolution of recycled concrete after carbonization at high temperature under axial compression

作　　者：崔正龙 孙万吉 费海超 李正元 CUI Zhenglong;SUN Wanji;FEI Haichao;LI Zhengyuan(School of Civil Engineering,Liaoning Technical University,Fuxin 123000,Liaoning,P.R.China)

机构地区：[1]辽宁工程技术大学土木工程学院,辽宁阜新123000

出　　处：《土木与环境工程学报（中英文）》2024年第4期175-185,共11页Journal of Civil and Environmental Engineering

基　　金：辽宁省教育厅基金(LJ2019JL023);辽宁工程技术大学学科创新团队资助(LNTU20TD-26)。

摘　　要：为研究再生混凝土在碳化高温下的损伤演化规律,对碳化后不同温度梯度(常温20℃、中低温200℃及中高温400℃)下C30再生混凝土(质量分数取代率0%、50%、100%)进行轴心受压试验并同步采集声发射信号,在分析声发射特征参数的基础上建立再生混凝土的损伤模型。结果表明,通过对声发射损伤定位、累计撞击计数与能量计数分析,可实现再生混凝土轴心受压破坏从初始损伤到微裂缝演变,再到宏观裂缝扩展,最终到试件破坏的全过程动态监测;不同粗骨料取代率再生混凝土试件,加载过程中损伤点的密集集中位置与试件最终破坏位置相符;随着温度梯度增加,3种不同粗骨料取代率的再生混凝土均呈现初始损伤增大、声发射参数增大、应力减小的现象;基于声发射累计撞击计数建立的混凝土损伤模型可用于分析碳化高温后再生混凝土轴心受压损伤演化规律。In order to study the damage evolution of recycled concrete under high temperature of carbonation,the experiments were conducted on C30 recycled concrete(0%,50%and 100%mass fraction replacement)under different temperature gradients(room temperature 20℃,medium and low temperature 200℃,and medium and high temperature 400℃)after carbonation with axial compression tests and simultaneous acquisition of acoustic emission(AE)signals,and the damage model of recycled concrete was established based on the analysis of acoustic emission characteristic parameters.The test results show that,analyzed AE damage location,cumulative impact count and energy count,dynamic monitoring of recycled concrete(RC)axial compression failure was realized from initial damage to micro fracture evolution,then to macro fracture propagation and finally to specimen failure;for RC specimens with different replacement ratio of coarse aggregate for comparison,the dense and concentrated location of damage points was the same as the failure position during loading process.Furthermore,RC with three different replacement ratios of coarse aggregate have the initial damage increases,the AE parameters increase and the stress decreases with the increase of temperature gradient.As a result,the concrete damage model based on AE cumulative impact count can be used to analyze the damage evolution law of RC after carbonization at high temperature under axial compression.

关 键 词：碳化高温 再生混凝土 声发射 轴心受压 损伤演化 

分 类 号：TU528.59[建筑科学—建筑技术科学]