Synergistic enhancement of mechanical and impermeability properties in self-healing concrete through PVA fiber reinforcement and MICP

Abstract

The mechanical strength and impermeability of concrete are critical to its structural reliability and long-term durability. However, conventional concrete lacks autonomous crack-healing capacity, which can lead to progressive degradation under sustained mechanical and environmental stresses. This study presents a novel self-healing concrete system incorporating polyvinyl alcohol (PVA) fibers and microbially induced calcium carbonate precipitation (MICP), designed to synergistically improve both material performance and crack-sealing efficiency. Experimental results indicate that the inclusion of PVA fibers significantly enhances mechanical and durability properties. Compared to plain concrete, the 28-day compressive and flexural strengths increased by 32.47 % and 22.54 %, respectively, while water penetration depth was reduced by 23.25 %. Moreover, the relative permeability coefficient and volume of harmful capillary pores decreased by 50.81 % and 19.27 %, respectively. After 28 days of autonomous healing, the specimens exhibited a compressive strength recovery rate of 66.59 % and an ultrasonic pulse velocity recovery of 58.82 %. Microstructural analysis confirmed the precipitation of dense calcite crystals within cracks, contributing to pore refinement and intrinsic property enhancement. This work not only advances the autonomous healing capability of concrete but also substantially improves its mechanical and impermeable performance, offering a promising strategy for developing highly durable construction materials.