Self-healing capacity of ultra-rapid-hardening fiber-reinforced cementitious composites under tension

This study investigates the self-healing capacity of ultra-rapid-hardening fiber-reinforced cementitious com-posites. For this purpose, polyethylene (PE) fibers with three different lengths (6, 9, and 12 mm) were incor-porated with different volume fractions of 1.0, 1.5, and 2.0%. All test series were pre-damaged with 0.5 and 1.0% pre-strains and re-tested after 30 wet-dry healing cycles. The fiber reinforcing index was proportional to the tensile performance regardless of the pre-strain and the length of the PE fiber was more dominant than the volume fraction. The case in which self-healing occurred most appropriately was for specimens that incorporated 2% of medium-length (9 mm) fibers. Thirty wet-dry cycles improved the tensile strength by up to 47.5% compared to the conventional one, while the strain capacity was reduced, resulting in a recovery ratio of only 74.5%. The energy absorption capacity was sufficiently recovered to be comparable to that of the control specimen and excellent strain-hardening behavior was obtained with a sufficient number of additional micro -cracks. Microcracks with widths of less than 50 mu m were filled significantly with the formation of CaCO3 crystals, which was verified by scanning electron microscopy and energy dispersive X-ray spectroscopy.

Automated summary

This study investigates the self-healing capacity of ultra-rapid-hardening fiber-reinforced cementitious composites. Different lengths of polyethylene (PE) fibers were incorporated with different volume fractions. The fiber reinforcing index was proportional to the tensile performance, with the length of the PE fiber being more dominant. Specimens with 2% medium-length fibers showed the most appropriate self-healing behavior.