Mechanical response analysis of self-healing cementitious composites with microcapsules subjected to tensile loading based on a micromechanical damage-healing model

Abstract

For the past several years, research in the field of self-healing construction materials becomes a hotspot with broad application prospects. This paper mainly focuses on the self-healing cementitious composites with microcapsules. To quantitatively interpret the self-healing effect of micro-encapsulated healing agents on microcrack-induced damage, a three-dimensional evolutionary micromechanical model is established to predict the mechanical response of the cementitious composites with the microcapsules subjected to tensile loading during the damage-healing process. The evolutionary domains of microcrack growth (DMG) and the corresponding compliances at the initial, activated and repaired stages are obtained. On the basis of the proposed 3D micromechanical model of the self-healing cementitious composites with microcapsules, elaborate studies of constitutive relations and compliance are conducted to investigate the effects of various system parameters involving the healing efficiency, fracture toughness and preloading-induced damage degrees on the compliances and stress-strain relations. The results indicate that relatively significant healing efficiency, preloading-induced damage degree and the fracture toughness of polymerized healing agent with the matrix will lead to higher tensile strength and stiffness. However, based on the two different failure modes of self-healing concrete, the excessive values of healing efficiency, preloading-induced damage degree and the fracture toughness of polymerized healing agent with the matrix will not affect the tensile strength of the cementitious composites. For the sake of the desired optimal healing effect, the specific parameters of both the matrix and the microcapsules should be selected carefully.