Investigation of chloride resistance in self-healing mortars using vegetative cell and spore-based MICP methods
Issued Date
2025-09-26
Resource Type
ISSN
09500618
Scopus ID
2-s2.0-105012949527
Journal Title
Construction and Building Materials
Volume
493
Rights Holder(s)
SCOPUS
Bibliographic Citation
Construction and Building Materials Vol.493 (2025)
Suggested Citation
Limpaninlachat P., Noppakun N., Chindasiriphan P., Intarasoontron J., Kunawisarut A., Jongvivatsakul P., Pungrasmi W., Likitlersuang S. Investigation of chloride resistance in self-healing mortars using vegetative cell and spore-based MICP methods. Construction and Building Materials Vol.493 (2025). doi:10.1016/j.conbuildmat.2025.143081 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/111693
Title
Investigation of chloride resistance in self-healing mortars using vegetative cell and spore-based MICP methods
Author's Affiliation
Corresponding Author(s)
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Abstract
This study focuses on chloride resistance of self-healing mortar specimens treated using two microbially induced calcium carbonate precipitation (MICP) methods: (1) the dropping method involving the application of vegetative bacterial cell solution into surface cracks, and (2) the embedding method involving the incorporation of microencapsulated bacterial spores into the mortar mix. Two ranges of crack width were considered: fine (<175 µm) and large (175–350 µm). In the dropping method, bacterial cell-to-nutrient ratios of 20:500 µL and 40:1000 µL were applied, while 1 % and 2 % dosages of microencapsulated spores with nutrients were used in the embedding method. Healing efficiency was evaluated through crack monitoring under 14 wet-dry cycles. Chloride resistance was assessed using rapid chloride migration testing and supported by microstructural analysis. Results show that the dropping method enabled rapid and effective crack repair, achieving 100 % closure of fine cracks with a bacterial cell-to-nutrient ratio of 40:1000 µL. This method also delivered the highest chloride resistance among all treatments, closely matching that of plain uncracked mortar by sealing surface cracks and forming a robust barrier against chloride ingress. In contrast, microencapsulated spores exhibited slower healing rate but promoted deeper mineral precipitation along the crack depth. The 2 % microencapsulated spore treatment achieved up to 72.9 % crack closure after 14 cycles. However, the increased matrix porosity due to nutrient additives led to reduced overall chloride resistance in spore-treated specimens. Overall, the high-dosage vegetative cell in dropping method proved more effective for surface crack sealing and enhancing durability, underscoring its potential for improving the long-term performance of cement-based materials in chloride-rich environments.