Effect of Plant-Derived Urease-Induced Carbonate Formation on the Strength Enhancement of Sandy Soil

Enhancing the Strength of Sandy Soil Through Enzyme-Induced Calcite Precipitation

“…Enzyme-induced calcite precipitation (EICP), a bioinspired soil improvement method, is receiving much attention in the field of biogeotechnology [9][10][11][12]. In EICP, the free urease enzyme triggers ureolysis reactions in the presence of calcium ions; ureolysis-driven calcium carbonate precipitate (CaCO 3 ) is produced within the soil matrix [13,14].…”

“…Several EICP-related studies have shown contradictory results withregard to the optimal CCR resulting in the highest calcium carbonate content, which in turn leads to improved geomechanical properties of the soil. Some have shown that increasing CCR to a certain level has a detrimental effect on the precipitation of calcium carbonate [11,19], whereas others have reported the opposite [13,18] Dilrukshi and Kawasaki [9] evaluated the effect of CCR (CaCl 2 -urea), urease, and curing period on the unconfined compressive strength (UCS) of sandy soil; the findings have shown that the increase in curing period and CCR (0.3-0.7 M) resulted in an increase in the estimated UCS value from 500 kPa to 4 MPa, whereas the performance of low and high urease activity was more efficient at low and high CCR, respectively. The high strength obtained in the study when compared with others may be as a result of the testing method adopted to evaluate the unconfined compressive strength.…”