Crack self-healing in bio-green concrete

Abstract Eco-efficient concrete produced by alkali-activation of recycled by-products has increased susceptibility to cracking. This study investigates the potential of S. pasteurii bacteria to impart crack self-healing in such green concrete. Porous expanded glass granules made from recycled glass were used, for the first time, as bacterial and nutrient carriers. Scanning electron microscopy, Raman spectroscopy, capillary water absorption, and inductively coupled plasma optical emission spectroscopy were deployed to investigate self-healing efficiency in the bio-green concrete under various environmental exposure. Crack widths up to 111 μm for moist-dry cured specimens incorporating bacteria were completely healed within 90 days, while no self-healing was observed in the control specimens. The sorptivity coefficient in specimens incorporating S. pasteurii bacteria was also much lower. SEM-EDS combined with Raman spectroscopy indicated that the dominant self-healing product was calcite. This study elucidates crack remediation in AAMs and demonstrates the potential of this novel biogenic self-healing system in green concrete structures.