Durability improvement assessment in different high strength bacterial structural concrete grades against different types of acids

• Published in: Sadhana (Bangalore) 2014-12, Vol.39 (6), p.1509-1522
• Main Authors: ANDALIB, RAMIN, ABD MAJID, M ZAIMI, KEYVANFAR, A, TALAIEKHOZAN, AMIRREZA, HUSSIN, MOHD WARID, SHAFAGHAT, A, ZIN, ROSLI MOHD, LEE, CHEW TIN, FULAZZAKY, MOHAMMAD ALI, HAIDAR ISMAIL, HASRUL
• Format: Article
• Language: English
• Subjects: Bacteria; Calcite; Concrete industry; Concretes; Durability; Engineering; High strength; Microorganisms; Portland cements
• ISSN: 0256-2499; 0973-7677
• DOI: 10.1007/s12046-014-0283-0

This paper provides an insight into a new biotechnological method based on calcite precipitation for achieving high strength bio-concrete durability. It is very clear that mineral precipitation has the potential to enhance construction material resistance towards degradation procedures. The appropriate microbial cell concentration (30 ∗ 10 5 cells/ml) was introduced onto different structural concrete grades (40, 45 and 50 MPa) by mixing water. In order to study the durability of structural concrete against aggressive agents, specimens were immersed in different types of acids solution (5% H 2 SO 4 and HCl) to compare their effects on 60 th , 90 th and 120 th day. In general, sulphuric acid and hydrochloric acid are known to be the most aggressive natural threats from industrial waters which can penetrate concrete to transfer the soluble calcium salts away from the cement matrix. The experimental results demonstrated that bio-concrete has less weight and strength losses when compared to the ordinary Portland cement concrete without microorganism. It was also found that maximum compressive strength and weight loss occurred during H 2 SO 4 acid immersion as compared to HCl immersion. The density and uniformity of bio-concrete were examined using ultrasonic pulse velocity (UPV) test. Microstructure chemical analysis was also quantified by energy dispersive spectrometer (EDS) to justify the durability improvement in bacterial concrete. It was observed that less sulphur and chloride were noticed in bacterial concrete against H 2 SO 4 and HCl, respectively in comparison to the ordinary Portland cement concrete due to calcite deposition.