Application of soybean powder as urease enzyme replacement on EICP method for soil improvement technique

Abstract

Many researchers have confirmed the application of calcite precipitation method by urease enzyme induction as a potential soil improvement technique. However, this method needs an expensive investment due to the urease enzyme issue. The enzyme itself brings 90% of the total materials cost. It means that finding new inexpensive material for replacing the enzyme is considered essential for the development of this method. In this study, a potential material, which is soybean powder, was evaluated through several experimental tests. A comparison of urease activity value between EICP using soybean powder and commercial urease as a catalyst for hydrolysis of urea compound was made through a series of conductivity tests. It was found that EICP using soybean urease can be a potential alternative to a commercial product in terms of urease activity. The precipitation materials were analysed using a microscale test to analyses the minerals type. Besides, the reinforcing effect of EICP solution on soil specimens was evaluated by conducting unconfined compressive strength (UCS) test and acid leaching test. The results of the UCS test were indicated that the soybean powder is a potential material to be used in soil improvement technique.