| 摘要: |
| 为研究橡胶对自密实混凝土断裂性能的影响,针对4种橡胶掺量（0%、10%、20%和30%）的自密实混凝土,采用声发射（AE）技术,开展三点弯曲梁断裂试验,获得其荷载裂缝口张开位移（P CMOD）曲线、断裂能及声发射特征参数.通过荷载、累计振铃计数和累计撞击次数随时间的变化关系曲线,分析了橡胶掺量对自密实混凝土边界效应的影响.利用声发射源定位,确定橡胶自密实混凝土断裂过程区的宽度,计算得到上升角(RA)和平均频率(AF)值,分析了橡胶自密实混凝土的破裂模式.结果表明：随着橡胶掺量的增加,自密实混凝土的延性和韧性均有所提高,其声发射特征表现为橡胶自密实混凝土的边界区域长度和信号活度减小,断裂过程区的宽度和拉伸裂纹的比例增大;橡胶颗粒对能量的吸收和扩散作用是橡胶自密实混凝土断裂性能得以改善的重要原因. |
| 关键词: 橡胶自密实混凝土 橡胶掺量 断裂性能 声发射 |
| DOI：103969/j.issn.1007 9629202104012 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目（51979090）;江苏省自然科学优秀青年基金资助项目（BK20190075）;中央高校基本科研业务费专项资金资助项目（B200202076） |
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| Fracture Properties and Acoustic Emission Characteristics of Rubber Self compacting Concrete |
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CHEN Xudong, HUANG Yebo, CHEN Chen
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College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China
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| Abstract: |
| To study the influence of rubber on the fracture properties of self compacting concrete, the three point bending fracture tests of self compacting concrete with four different rubber contents(0%, 10%, 20%, 30%) were carried out by applying acoustic emission(AE) technology. Based on the test results, the curve of P CMOD, fracture energy and the characteristic parameters of acoustic emission were obtained. The influence of rubber content on the boundary effect was analyzed by drawing the relation curves of load, cumulative counts, cumulative hits and time. The width of the fracture process zone was obtained by the source location methods of AE. The fracture mode of specimen was analyzed by calculating the values of rise angle(RA) and average frequency(AF). The results show that with the increase of rubber content, the ductility and toughness of self compacting concrete are improved, while the AE characteristics are as follows:the length of the boundary area and the signal activity decrease, while the width of the fracture process zone and the ratio of tensile crack increase. The energy absorption and diffusion effect of rubber particles play an important role in improving the fracture properties of rubber self compacting concrete. |
| Key words: rubber self compacting concrete rubber content fracture property acoustic emission(AE) |
