We investigated microcrack behavior in encapsulation-based self-healing concrete subjected to uniaxial tension by using finite element analysis. 3D circular capsule with particular shell thickness embedded in the mortar matrix samples was modeled. To represent potential cracks, zero thickness cohesive elements with bi-linear traction-separation law were pre-inserted into the initially generated meshes. Effects of fracture strength variation among the mortar matrix, the capsule, and the interface between them on crack nucleation, initiation, and propagation were investigated. The results showed that the mismatch among fracture strengths of the capsule, the mortar matrix, and the interface of them has a significant influence on crack nucleation, initiation, and propagation. Using similar fracture strength between capsule and mortar matrix, together with high fracture strength of their interface, will initiate a crack from the mortar matrix and then propagate directly into the capsule. This condition is the most favorable case in the capsule-based self-healing concrete since a capsule contained with a healing agent will likely fracture. Thus, the self-healing process in the concrete can be achieved effectively. In addition, the interface with lower fracture strength than the mortar matrix and the capsule strengths will initiate a crack from the interface and then leave the capsule intact. Hence, the self-healing mechanism could not be achieved. These results will become some valuable assets for the experimentalists to assist in their experimental works.

我们通过使用有限元分析，研究了在单轴拉伸作用下基于封装的自愈混凝土中的微裂纹行为。对砂浆基质样品中嵌入特殊壳厚的3D圆形胶囊进行了建模。为了表示潜在的裂缝，将具有双线性牵引力-分离定律的零厚度粘结元件预先插入到最初生成的网格中。研究了砂浆基体，囊体以及它们之间的界面之间的断裂强度变化对裂纹成核，萌生和扩展的影响。结果表明，胶囊，砂浆基质及其界面的断裂强度之间的不匹配对裂纹的形核，引发和扩展具有重大影响。在胶囊和砂浆基质之间使用类似的断裂强度，加上界面的高断裂强度，会从砂浆基质中产生裂纹，然后直接传播到胶囊中。这种情况在基于胶囊的自修复混凝土中是最有利的情况，因为包含愈合剂的胶囊很可能会破裂。因此，可以有效地实现混凝土中的自修复过程。另外，具有比砂浆基质更低的断裂强度的界面和囊的强度将从界面引发裂纹，然后保持囊完整。因此，无法实现自我修复机制。这些结果将成为实验者协助其实验工作的宝贵资产。会从砂浆基质中产生裂纹，然后直接传播到胶囊中。这种情况在基于胶囊的自修复混凝土中是最有利的情况，因为包含愈合剂的胶囊很可能会破裂。因此，可以有效地实现混凝土中的自修复过程。另外，具有比砂浆基质更低的断裂强度的界面和囊的强度将从界面引发裂纹，然后保持囊完整。因此，无法实现自我修复机制。这些结果将成为实验者协助其实验工作的宝贵资产。会从砂浆基质中产生裂纹，然后直接传播到胶囊中。这种情况在基于胶囊的自修复混凝土中是最有利的情况，因为包含愈合剂的胶囊很可能会破裂。因此，可以有效地实现混凝土中的自修复过程。另外，具有比砂浆基质更低的断裂强度的界面和囊的强度将从界面引发裂纹，然后保持囊完整。因此，无法实现自我修复机制。这些结果将成为实验者协助其实验工作的宝贵资产。可以有效地实现混凝土的自我修复过程。另外，具有比砂浆基质更低的断裂强度的界面和囊的强度将从界面引发裂纹，然后保持囊完整。因此，无法实现自我修复机制。这些结果将成为实验者协助其实验工作的宝贵资产。可以有效地实现混凝土的自我修复过程。另外，具有比砂浆基质更低的断裂强度的界面和囊的强度将从界面引发裂纹，然后保持囊完整。因此，无法实现自我修复机制。这些结果将成为实验者协助其实验工作的宝贵资产。