Macro-micro experimental investigation on the behavior of EICP-treated sands

In recent years, growing environmental concerns about ecosystem pollution and global warming have spurred considerable efforts to reduce the use and production of environmentally unfriendly materials. In this regard, biological or bio-inspired approaches, such as enzyme-induced calcium carbonate precipitation (EICP), have recently become eco-friendly techniques in geotechnical engineering for soil improvement. This technique uses a mixed solution composed of urea, calcium chloride, and the urease enzyme as the soil grouting material, producing calcite (CaCO۳) as a binder. In this study, to reduce costs, the urease enzyme extracted from soybean seeds was used in the EICP method to improve the mechanical behavior of Firoozkuh No. ۱۶۱ sand. The macro- and micro-scale behavior of EICP-treated specimens with varying parameters such as molarity of cementation solution, relative density of sand, number of treatment cycles, and the amount and activity of urease enzyme have been investigated using the unconfined compression strength (UCS) test and scanning electron microscopy (SEM). The results showed that the precipitated calcium carbonate improved soil strength and stiffness by filling the voids, roughening the grain surfaces, and bonding the particles. Finally, this non-destructive approach is proposed as a sustainable soil improvement alternative to environmentally harmful materials.

کلیدواژه ها:

EICP ، Calcite ، Urease ، UCS test ، SEM