FEASIBILITY ASSESSMENT OF NEWLY ISOLATED CALCIFYING BACTERIAL STRAINS IN SELF-HEALING CONCRETE

Abstract

In the present study, rarely explored spore former (Bacillus safensis & Bacillus pumilus) and non-spore former (Arthrobacter luteolus, Chryseomicrobium imtechense & Corynebacterium efficiens) alkaliphilic calcifying microbes were evaluated for their prolonged survival in cementitious environment. Extensive experimental program was designed to examine mechanical, self-healing, microstructural modifications and durability of self-healing concrete (SHC). Results of the experimental program endorsed the survival of all bacterial strains in the harsh concrete environment along-with improved mechanical response of matrix. Moreover, investigated strains were capable of precipitating copious amount of calcite having maximum of 0.8 mm average crack healing with 86 % strength recovery. Densification of microstructure was evident from the microstructural evaluation and pore refinement. SHC portrayed a significant resistance of 50 % and 20 % against Cl- penetration and sulphate attack. Conclusively, these strains have potential to impart sustainability in concrete structures by extending the structural life, subsiding repairs cost and conserving the natural resources.