Abstract:
The research w o r k aims to assess the feasibility of i n t r o d u c i n g the microbial induced
carbonate p r e c i p i t a t i on (MICP) as an alternative technique for surface stabilization
of the cut slopes by augmenting potential indigenous ureolytic bacteria. A set of
column solidification tests was conducted on embankment soil (Hokkaido
expressway, Japan) to optimize the performance of bacteria regarding bacterial
population of culture solution (optical density (OD600) from 1 to 6), and
concentration of Ca^* and urea i n cementation solution (0.5 m o l / L and 1 mol/L) at
the temperature of 20°C. The UCS of treated samples was estimated using needle
penetrometer, and the microstructure of the treated specimens was observed using
scanning electron microscope (SEM). The results reveal that the UCS of the
specimen increases w i t h increasing ODeoo w i t h o u t any clogging w i t h i n the samples.
Treating the soil using 1 m o l / L concentrated (Ca2+ and urea) cementation solution
and bacterial culture w i t h ODeoo of 6 results the highest UCS of 7.5 MPa while
achieving relatively a homogeneous solidification along the column profile. The
micrographs of the treated specimen confirms that the rombohedral calcium
carbonate crystals formed w i t h i n the pores of soil matrix, w h i c h has effectively
bonded the adjacent soil particles, and contributed to enhance the strength
significantly at the o p t i m i z e d treatment condition.
Citation:
Gowthamani, S., Nakashima, K., Ebina, K., & Kawasaki, S. (2018). Experimental optimization of biocement formation: alternative countermeasure for surface erosion of cut slope. In A.M.K.B. Abeysinghe & G.V.I. Samaradivakara (Eds.), Proceedings of International Symposium on Earth Resources Management & Environment 2018 (pp. 97-103). Department of Earth Resources Engineering, University of Moratuwa.