Bulletin of the Geological Society of Malaysia, Volume 67, June 2019, pp. 75 – 81

Microbially induced carbonate precipitations to improve residual soil at various temperatures

Henry Ting Pek Kong¹, Khairul Anuar Kassim¹, Murtala Umar², Muttaqa Uba Zango^1,3,*, Abubakar Sadiq Muhammed^1,4, Kamarudin Ahmad¹

1 Department of Geotechnical & Transportation Engineering, Universiti Teknologi Malaysia, Skudai 81310, Johor, Malaysia
2 Department of Civil Engineering, Faculty of Engineering, Bayero University Kano, PMB 3011 Kano, Nigeria
3 Department of Civil Engineering, Kano University of Science and Technology, Wudil, PMB 3244 Kano, Nigeria
4 Department of Civil and Water Resources Engineering, University of Maiduguri, P.M.B. 1069, Maiduguri, Nigeria
*Corresponding author email address: muttaqaubaz@yahoo.com

Abstract: Microbial induced carbonate precipitation (MICP) has emerged recently as a new approach of green and sustainable soil improvement technique. The main aim of this study was to determine the most suitable temperature for MICP to improve tropical residual soil. The physical and engineering properties of residual soil used in the study were determined through several laboratory experiments. A urease active strain of Sporosarcinapasteurii obtained from American Type Culture Collection (ATCC) was used to trigger the carbonate precipitation. Experimental parameters such as curing temperature, treatment duration and bacteria to cementation reagents ratios were evaluated. The results show that the optimum temperature for MICP treatment of residual soil is 55°C. It was also found that at this optimum temperature, specimens treated with bacteria and cementation reagents in proportion of 2:1 produces the highest strength improvement ratio of 1.27 relative to untreated sample and calcite content of 1.09% after 7-day curing. The shear strength of the treated soil also increases with the increase in treatment durations as the 7 days curing produces higher strength improvement for all the experimental conditions. The specimens cured under the atmospheric temperature recorded the lowest calcite content and hence the lower shear strength improvement ratio. Moreover, the experimental results obtained from this study also can be used as a guide in the future bio-geotechnology researches and lead to further scope in geotechnical applications.

Keywords: Microbial induced carbonate precipitation, MICP, shear strength, temperature, residual soil

DOI : https://doi.org/10.7186/bgsm67201909