基于声发射技术的再生混凝土冻融损伤特性研究  

Damage characteristics of recycled aggregate concrete subjected to freeze-thaw deterioration based on acoustic emission technology

作　　者：张恺 尹志刚[2] 陈晨 董思健 周晶[1] ZHANG Kai;YIN Zhigang;CHEN Chen;DONG Sijian;ZHOU Jing(School of Hydraulic Engineering,Dalian University of Technology,Dalian 116024,China;Laboratory of Applied Disaster Prevention in Water Conservation Engineering of Jilin Province,Changchun Institute of Technology,Changchun 130012,China;Department of Civil Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]大连理工大学水利工程学院,辽宁大连116024 [2]长春工程学院吉林省水工程安全与灾害防治工程实验室,吉林长春130012 [3]清华大学土木工程系,北京100084

出　　处：《人民长江》2023年第8期221-226,共6页Yangtze River

基　　金：吉林省科技厅资助项目(20210203141SF,20220508146RC)。

摘　　要：为研究不同冻融介质(清水、3.5%NaCl溶液)对再生混凝土冻融损伤和声发射特性的影响,对再生粗骨料替代率为50%的混凝土开展快速冻融试验。利用声发射技术对冻融后的再生混凝土受压全过程进行监测,以声发射特性参数作为损伤变量,分析不同冻融介质下再生混凝土的冻融损伤劣化特征。结果表明:在3.5%(质量比)NaCl溶液中的再生骨料混凝土的冻融破坏程度要远大于清水组中混凝土的冻融破坏程度,且两者之间的差异随冻融次数的增加而增大;声发射能量释放率的峰值随冻融次数呈逐渐降低的趋势,不同冻融次数后声发射相对累积能量随相对应力水平的增加而逐渐增大,曲线的拐点逐渐右移。建立的声发射相对累积能量-应力曲线能够较好地反映再生骨料混凝土冻融后受压破坏的全过程。研究成果可为研究再生混凝土冻融损伤演化规律提供参考。In order to study the effect of different freeze-thaw media(water,3.5wt%NaCl solution)on the freeze-thaw damage and acoustic emission(AE)characteristics of recycled aggregate concrete(RAC),a series of experiments have been carried out by using concrete with 50%recycled coarse aggregate.AE technology was utilized to monitor the whole process of compression of RAC after freeze-thaw cycles,and the frost damage characteristics of RAC under different mediawas represented by AE parameter.The results indicated that the freeze-thaw deterioration of RAC in 3.5wt% NaCl solution was much worse than that in water,and the deterioration difference in the two media increased with the increasing of freeze-thaw cycles.Besides,the peak value of AE energy release rate gradually decreased with the increasing of freeze-thaw cycles.The relative cumulative energy of AE increased with the increasing of relative stress level,and inflection point of the curve moved to the right gradually.The curve of AE relative cumulative energy and stress obtained by experiments can reflect the whole process of compressive failure of RAC after frost damage effectively.This work can provide a reference for the study of freeze-thaw damage evolution of RAC.

关 键 词：再生混凝土 冻融介质 声发射技术 损伤 

分 类 号：TU528.0[建筑科学—建筑技术科学]