The cementitious composites with microencapsulated healing agents have become a class of hotspots in the field of construction materials, and they have very broad application prospects and research values. The in-depth study on multi-scale mechanical behaviors of microencapsulated self-healing cementitious composites is critical to quantitatively account for the mechanical response during the damage-healing process. This paper proposes a three-dimensional evolutionary micromechanical model to quantitatively explain the self-healing effects of microencapsulated healing agents on the damage induced by microcracks. By virtue of the proposed 3 D micromechanical model, the evolutionary domains of microcrack growth (DMG) and corresponding compliances of the initial, extended and repaired phases are obtained. Moreover, the elaborate studies are conducted to inspect 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 a higher compressive strength and stiffness. However, the specimen will break owing to the nucleated microcracks rather than the repaired kinked microcracks. Further, excessive higher values of healing efficiency, preloading-induced damage degree and the fracture toughness of polymerized healing agent with the matrix will not affect the compressive strength of the cementitious composites. Therefore, a stronger matrix is required. To achieve the desired healing effects, the specific parameters of both the matrix and microcapsules should be selected prudently.

具有微囊化愈合剂的胶结复合材料已成为建筑材料领域的一类热点，具有非常广阔的应用前景和研究价值。深入研究微囊自修复水泥基复合材料的多尺度力学行为，对于定量评估损伤修复过程中的机械响应至关重要。本文提出了一个三维进化微力学模型，以定量解释微囊化愈合剂对微裂纹所致损伤的自我修复作用。借助于提出的3D微力学模型，获得了微裂纹生长（DMG）的演化域以及初始，扩展和修复阶段的相应顺应性。而且，进行了详尽的研究，以检查各种系统参数（包括愈合效率，断裂韧性和预压引起的损伤程度）对柔顺性和应力-应变关系的影响。结果表明，相对较高的愈合效率，预加载引起的破坏程度以及聚合愈合剂与基体的断裂韧性将导致较高的抗压强度和刚度。但是，标本会由于成核的微裂纹而不是修复的扭结微裂纹而破裂。此外，过高的愈合效率值，预加载引起的破坏程度以及聚合的愈合剂与基质的断裂韧性不会影响胶凝复合材料的抗压强度。因此，需要更强的矩阵。