Damage investigation of ultra high performance concrete under direct tensile test using acoustic emission techniques
Damage investigation of ultra high performance concrete under direct tensile test using acoustic emission techniques
复制标题
使用声发射技术进行直接拉伸试验下超高性能混凝土的损伤研究
DOI：
10.1016/j.cemconcomp.2018.01.007
复制
发表时间：
2018-04-01
影响因子：
10.5
通讯作者：
Guo, Jun-Yuan
中科院分区：
文献类型：
--
作者：
Wang, Jun-Yan;Guo, Jun-Yuan
本研究采用声发射（AE）分析方法监测超高性能混凝土（UHPC）在直接拉伸试验中的损伤演变过程。研究了高应变硬化型、低应变硬化型和应变软化型三种UHPC。同时，测量了UHPCs在拉伸试验过程中的裂纹宽度发展情况。试验结果表明，高应变硬化UHPC在应变硬化阶段形成多个肉眼看不见的微裂纹（一般小于0.05 mm），表现出较高的塑性。裂缝宽度-应变曲线表明，提高超高强度混凝土的极限拉伸应变能有效提高其裂缝宽度控制能力。声发射分析方法可以有效检测高应变硬化UHPC在600 μ epsilon应变下的内部损伤。此时裂缝宽度小于0.01 mm，本研究中裂缝宽度测量仪无法检测到。对于三种类型的超高性能混凝土，在应变软化阶段，局部裂纹周围都产生了损伤。综上所述，声发射分析方法为UHPC在应变硬化阶段的多重裂纹行为提供了有力的证据，并为三种类型的UHPC在应变软化阶段具有相同的损伤演化机制提供了清晰的解释。(C) 2018 Elsevier Ltd.版权所有。
In this study, acoustic emission (AE) analysis method was applied to monitor the damage evolution process of ultra high performance concrete (UHPC) under direct tensile test. Three types of UHPCs, including high strain-hardening UHPC, low strain-hardening UHPC and strain-softening UHPC were investigated. Meanwhile, the crack width developments of UHPCs during the tensile test were measured. Test results show that high strain-hardening UHPC exhibited high ductility by forming multiple microcracks invisible to naked eyes (typically below 0.05 mm) in the strain-hardening stage. The crack width-strain curves indicate that increasing the ultimate tensile strain of UHPC can improve its crack width control ability effectively. The AE analysis method could effectively detect the internal damages of the high strain-hardening UHPC at a strain of 600 mu epsilon. At that time, the crack width was smaller than 0.01 mm that could not be detected by crack width measuring instrument in this study. For three types of UHPCs, damages were generated around the localized crack during the strain-softening stage. In a word, the AE analysis method provides strong evidence to the multiple cracking behavior of UHPC during the strain-hardening stage, and provides a clear explanation to the identical damage evolution mechanism for three types of UHPCs during the strain-softening stage. (C) 2018 Elsevier Ltd. All rights reserved.