Bio-Mediated Soil Improvement under Various Concentrations of Cementation Reagent

Bio-mediated soil improvement is a relatively young technology in geotechnical engineering. The practical applications of the technique are still exposed to some uncertainties. This paper investigated the effect of the concentration of the cementation reagent on the performance of bio-mediated soil improvement. The shear strength, calcite content, pH, and ammonium content of the bio-mediated soil were measured under three concentrations of a cementation reagent, i.e. 0.25 M, 0.5 M, and 1 M. The results showed that the calcite precipitation and shear strength improved with the increased concentration of the cementation reagent up to 0.5 M. However, the improvement was retarded at higher concentration (i.e. 1.0 M). This is likely due to the inhibitory effect and halophilic characteristic of the bacteria used for the biocementation