Isolation of Sulphate Reduction Bacteria (SRB) to Improve Compress Strength and Water Penetration of Bio-Concrete

Abstract

The objective of this study is to isolate sulphate reduction bacteria (SRB) from acid mire water collected at Sg Pelepah Kota Tinggi, Johor Malaysia. The isolation process was conducted in high alkaline and anaerobic conditions to sustain the bacteria in concrete environment. Properties tests such as compressive strength and water penetration were conducted. The result showed that optimal growth condition of sulphate reduction bacteria is pH 9-10. It was also observed that the bacteria is a coccus shape after gram staining process. The bacteria was used after 10 days of culturing prior to growth curve measurement. The liquid culture containing sulphate reduction bacteria were used at 1%, 3% and 5% as replacement ratio of water content. Concrete specimens were cured in the air conditions for 7, 14 and 28 days. Maximum increment on compressive strength was 13.0% and decrement in water penetration was 8.5% occurred with 5% of SRB. The enhancement in compressive strength and water penetration performance was due to calcium precipitation within concrete pores. Image of scanning electronic microscopy (SEM) showed bacteria sustained and survived in concrete environment by reducing diameter of pores in concrete specimens.