Graduate Defense: Grant Goertzen

Dissertation Information

Title: Accelerating MICP Treatment Protocols Using Calcium Based Stabilizers Targeting Pavement Construction

Program: Master of Science in Civil Engineering

Advisor: Dr. Bhaskar Chittoori, Civil Engineering

Committee Members: Dr. Nick Hudyma, Civil Engineering and Dr. Yang Lu, Civil Engineering

Abstract

Crushed stone and gravel have long been favored soil types for base courses and bearing strata due to their strength and interlocking ability. However, due to concerns over resource depletion, environmental impacts, permitting costs, and the extensive drawbacks associated with quarrying, transporting gravels to a job site has become a less viable option. Instead, researchers are exploring methods of strengthening the native soils through various cementitious treatments such as hydrated lime, fly ash and cement. However these treatments also have significant environmental impacts due to the immense quantities of carbon dioxide released into the atmosphere during their production. A promising and sustainable approach to soil stabilization is Microbial Induced Calcite Precipitation (MICP), which leverages naturally occurring bacteria in the soil to precipitate and cement calcite crystals. This process reduces soil permeability and enhances its strength, particularly in granular soils. However, the effectiveness and timeliness of MICP can be limited in fine grained soils, which is a challenge for large-scale construction projects containing silts or clays. The primary objective of this research is to expedite the MICP treatment process by incorporating subsequent treatments with hydrated lime, cement, or fly ash. By combining the strengths of both stabilization methods, the research aims to reduce the amount of cementitious material needed to achieve the desired strength while also shortening the treatment time.