Mechanical Behaviors of MICP Treated Binary Granular Materials Under One-Dimensional Consolidation

The mechanical behaviors of binary granular materials are significantly different due to the amount of their fines content, which is normally categorized as coarse-grains dominant or fine-grains dominant. This study attempts to apply microbial technology to improve the strength and stiffness of binary granular materials. The technique uses microbial urea hydrolysis to induce calcite, which is also called microbiological-induced calcite precipitation (MICP). A series of one-dimensional consolidation tests were carried out to examine the compressive behavior of the materials before and after MICP treatment. The fines content evaluated in this study included 0, 15, and 30, while the relative density is 40%, and the grain size ratio of coarse grains to fine grains is 12. The single-phase treatment was introduced to minimize the sand being disturbed during the MICP process, where natural percolation from the bottom of the specimen was applied. The curing time of 3, 7 days was selected and each specimen in the consolidation ring was inundated with water for 24 h before the test. This study attempted to improve the binary mixtures with the MICP technique, to investigate the effect of MICP on the one-dimensional consolidation results. The results were the opposite of what was predicted.