Suitability and Challenges of Biomineralization Techniques for Ground Improvement

The biomineralization process is a relatively modern ground improvement technique wherein microbial activity is increased to improve soil stiffness. Bacteria and enzymes are used to carry out the ureolysis process which leads to the formation of calcium carbonate that binds the soil particles. Biopolymers are also used to improve the engineering properties of soil. This study aims to present a detailed insight into the efficacy of various methods with respect to the type of bio-agent, soil, optimal concentration, and solution injection scheme. The effect of the biomineralization techniques on soil engineering properties such as unconfined compressive strength, shear strength, and permeability is discussed. The cost-effectiveness is studied to help identify the total optimum production cost of different methods in accordance with the raw materials cost. The concept has been found to be especially useful in the mitigation of liquefaction hazards and the prevention of soil erosion. The existing literature primarily discusses the increase in the strength of soil post-process. The potential field applicability, related challenges, and problems are also presented in this review. The major challenge in adopting the technology at field is the cost of the treatment and the problem is obtaining uniform bio-mineralization across the depth of treatment. The cost-related issue can be handled using industrial by-products for the growth of bacteria, while engineering aspects of bio-mineralization have to be understood to make it field applicable.