Analyzing the macroscopic/mesoscopic mechanical properties and fatigue damage of graphene oxide/microcapsule self-healing concrete

Concrete materials used in transmission projects in Northwest China require specific properties, such as crack resistance, fatigue resistance, and low impedance. To meet these requirements, microcapsules with repair properties were synthesized using a physical method. Graphene oxide was employed as a conductive medium and reinforcing material to prepare standard concrete composite parts. Furthermore, the stress state and cracking behavior of the microcapsules in concrete were simulated through the Python-based secondary development of ABAQUS. An orthogonal test design was conducted to determine the optimal graphene oxide, microcapsule, and water–cement ratios. Based on the orthogonal test results, fatigue testing was conducted to assess the fatigue strength, fatigue life, and crack development behavior of the concrete under combined dynamic and static loading. The results show that the thickness of the microcapsule wall material directly influences the fracture extension and practicability of the concrete. Including a certain amount of graphene oxide can enhance the strength of the concrete, reduce its resistivity, and compensate for the microcapsule-induced early strength loss. The optimal graphene oxide/microencapsulated concrete ratios were determined as 3 % microcapsule admixture, 0.1 % graphene oxide admixture, and 0.45 water–cement ratio. Notably, at low stress levels, graphene oxide and microcapsules act synergistically to enhance concrete fatigue resistance. Graphene oxide/microencapsulated concrete exhibits higher residual fatigue strength than ordinary concrete; however, the difference in their fatigue resistance diminishes as the number of cycles increases.