Coupled effects of simultaneous autogenous self-healing and sustained flexural loading in cementitious materials

The self-healing efficiency of cementitious materials might be impaired by external loading. This study investigates the coupled effects of sustained flexural loading and self-healing mechanisms. To this end, prismatic mortar specimens were pre-cracked at two days with 10-mu m wide cracks under bending. Some beams were then immersed for healing and simultaneously loaded for about 4 weeks using an innovative three-point bending test device allowing bending creep displacement measurement. At the same time, reference beams were immersed without load. After the healing period, the specimens were reloaded to assess the effect of creep and healing on the stiffness and strength recovery. It was found that, during immersion, the creep deformation gradually decreased with time, probably due to the precipitation of healing products. However, after immersion, the mechanical properties recovery of specimens undergoing creep during self-healing decreased by 12 % compared to the reference specimens. Microscopic observations were consistent with the mechanical recovery measurements, suggesting partial healing of the loaded specimens.