Expansive cracking and compressive failure simulations of ASR and DEF damaged concrete using a mesoscale discrete model
Expansive cracking and compressive failure simulations of ASR and DEF damaged concrete using a mesoscale discrete model
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DOI：
10.1016/j.cemconcomp.2019.103404
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发表时间：
2019-11
影响因子：
10.5
通讯作者：
Yi Wang;Y. Meng;P. Jiradilok;Koji Matsumoto;K. Nagai;S. Asamoto
中科院分区：
文献类型：
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作者：
Yi Wang;Y. Meng;P. Jiradilok;Koji Matsumoto;K. Nagai;S. Asamoto
碱-硅酸反应(ASR)和延迟钙矾石形成(DEF)产生的内应力会导致混凝土开裂和力学性能下降，但这些现象之间的关系尚不清楚。本文采用三维刚体弹簧模型(3DRBSM)，在细观尺度上模拟了混凝土ASR和DEF膨胀后的裂缝形态以及抗压强度和弹性模量的损失。模型中引入了ASR和DEF引起的混凝土膨胀，分别在界面过渡区和砂浆单元的弹簧上施加初始应变作为损伤历史。在对单一骨料模型进行验证后，进一步分析了ASR和DEF损伤对混凝土开裂的影响差异。研究了ASR破坏情况下活性集料百分含量的影响，而DEF情况下考虑了不同的强化膨胀区。将模拟的混凝土力学性能损失与试验结果进行了比较，取得了较好的一致性。结果表明，力学性能的损失主要是由内部裂纹引起的，而不是表面裂纹的形式。抗压强度高度依赖于大裂纹的发展，而弹性模量与裂纹面的总数密切相关。更重要的是，无论是强化膨胀区，其力学性能都与膨胀开裂损伤相一致。
Internal stresses induced by the alkali silica reaction (ASR) and delayed ettringite formation (DEF) can cause cracking and degrade the mechanical properties of concrete, but the relationship between these phenomena remains unclear. In this study, crack patterns and the loss of compressive strength and elastic modulus of concrete after ASR and DEF expansion are simulated at the mesoscale using a three-dimensional Rigid Body Spring Model (3D RBSM). Concrete expansions induced by ASR and DEF are introduced in the model by applying initial strain on the springs of interfacial transition zone (ITZ) and mortar elements as damage history respectively. After verifying the model with single aggregate, further analysis of differences in concrete cracking due to ASR and DEF damage is carried out. The effect of the percentage of reactive aggregate is studied in the cases of ASR damage, while different intensified expansion areas are considered in the case of DEF. The simulated losses of mechanical properties of the concrete are compared with the experimental results and good agreement is obtained. It is found that the loss of mechanical properties is dominated by internal cracks rather than the surface crack pattern. Compressive strength is highly dependent on the development of large cracks while elastic modulus is closely related to the total number of cracked faces. More importantly, regardless of the intensified expansion area, the mechanical properties are consistent with expansive cracking damage.