Investigating the potential for porous ceramics as bacterial carrier in self-healing cemented paste backfill

Abstract

Waste porous ceramic (WPC), which remains in the industrial manufacturing process, is difficult to be disposed of. This study proposes a new idea for resource utilization of WPC, which means that WPC as a bacterial carrier applies in self-healing cemented paste backfill. The authors investigated the effects of WPC pore size, initial crack size, and bacterial concentration on the crack self-healing ratio of the backfill, analyzed the crack self-healing evolution process by photographing, and finally used a series of instruments to characterize the physical phase at the sample fracture and explain the mechanism. The results showed that the crack self-healing ratio of WPC with small pore size (pore size distribution of 1–2 mm) as the bacterial carrier was 13–22% higher than that of WPC with large pore size (pore size distribution of 3–4 mm) at 3–7 days. Also, the strength recovery ratio of the cemented paste backfill can be improved to 10–23% when adding bacteria-WPC. The self-healing ratio can reach 100% in 28 days for initial crack widths less than 1 mm, while the self-healing ratio decreases to 98% for widths near 2 mm. Additionally, the biomineralization ratio of the 1.5 mol/L embedded bacterial solution was 2.77–4.68% higher than that of 1.0 mol/L. WPC can effectively release the embedded bacterial solution once the backfill cracks appear, which proves the feasibility of WPC as a bacterial carrier. This study also lays the experimental and theoretical foundation for porous ceramic management.