Use of microbial technology to improve strength properties and permeability of soil

Microbially Induced Calcite Precipitation is an emerging technique for the ground improvement technology. This technique involves the use of bacteria, namely Sporosarcina pasteurii, to produce urease enzyme through the process of urea hydrolysis. Then, with supplied calcium chloride and urea along with nutrients for the bacteria, it will precipitate calcium carbonate crystals which will bind the soil particles together and improve the soil properties. Previous works were mainly conducted in one-dimensional columns which may have produced different results than those of 3D scale specimens. The experiments conducted were specimens with sizes of 50 mm and 150 mm cubes to study the feasibility of the method of injections and to evaluate its homogeneity within the sand matrix. Results were interpreted in terms of its unconfined compressive strength and the calcite content. This research has shown that with further improvement on the method of injections, the strength of sand in 3D scale condition can be further improved prior to its implementation for field work.