An Experimental Study on the Stabilization of Coral Gravel Beach using Bio-cement

Abstract

An experimental study on the stabilization of coral-gravel beach was performed using carbonate precipitation induced by microbial urease activity. The pilot experiment was done to solve scale-up problems from the bench scale experiments. In this study, microbes, ureolytic strains NO-A10 isolated from the domestic soils, were used to induce the hydrolysis of urea. The product of the hydrolysis was used to produce carbonate which acts as a binder (bio-cement) for coral gravels. The 70 cm thick coral gravel layer was cemented by injecting the bio-cement solution. The result showed that the gravels were strongly cemented with the carbonate precipitated. However, the experimental results could not be quantitatively predicted from the bench scale experiment. In this study, scale-up problems are discussed in terms of size effect, reaction velocity, distribution of microbes, transport distance of microbes, etc. This study will contribute to the success for actual construction.