Feasibility assessment of newly isolated calcifying bacterial strains in self-healing concrete

• Published in: Construction & building materials Vol. 362; p. 129662
• Main Authors: Shaheen, Nafeesa, Khushnood, Rao Arsalan, Memon, Shazim Ali, Adnan, Fazal
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 02.01.2023
• Subjects: Arthrobacter luteolus; Bacillus pumilus; Bacillus safensis; Chryseomicrobium imtechense; Corynebacterium efficiens; Self-healing concrete; Sustainable concrete; CC; Chryseomicrobium imtechense; OPC; XRD; Ca(OH)2; MICP; SHC; TG; CaCO3; Corynebacterium efficiens; ASTM; Arthrobacter luteolus; Bacillus pumilus; Bacillus safensis; SEM; SP; Self-healing concrete; Sustainable concrete
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2022.129662

•Both spore former and non-spore former novel species were able to survive in harsh environment.•Microbial instigated precipitation densified the concrete matrix and improved stress–strain response of concrete.•A maximum of 36% and 19 % increase was observed in compressive and split tensile strength.•SHC showed a significant resistance of 50% and 20% against Cl- penetration and sulphate attack.•The species of Arthrobacter, Chryseomicrobium and Corynebacterium emerged as new potential healing agent for SHC. 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.