Fatigue properties and microstructure of graphene oxide/microcapsule self-healing concrete

To meet the unique requirements of durability and conductivity of concrete materials for trans-formation projects in Northwest China, microcapsules with repair properties were synthesized us-ing a physical method. Graphene oxide was used to prepare standard concrete composite parts as a conductive medium. The orthogonal test determined the optimal dosage of graphene oxide and microcapsules. The fatigue test and microstructure of concrete under static loading and combined dynamic and static loading were investigated, and the effects of graphene oxide and microcap-sules on the fatigue resistance of concrete were compared and analyzed. Finally, the microscopic morphology of concrete was analyzed using scanning electron microscopy (SEM) to afford the microscopic mechanism of action for improving the mechanical properties and fatigue damage of concrete. The results show that the optimal mixing ratio of the concrete after 28 days is 3% mi-crocapsule content, 0.1% graphene oxide content, and 0.5 water-cement ratios. Graphene oxide can promote the hydration process of cement and improve the pore structure of the cement ma-trix to compensate for the loss of strength of concrete internal structure caused by microcapsules. The strong growth rate is not <20%. The fatigue life loss of the group doped with 0.1% graphene oxide alone and the best ratio group was relatively small under different stress levels. The micro -capsules were uniformly embedded within the cement matrix, and graphene oxide promoted the formation of a dense microstructure within the material. The synergistic effect of the two ensures structural integrity and denseness.