Scale-Up Soybean Crude Urease Calcite Precipitation (SCU-CP) Method for Sandy Soil Improvement

Abstract

Loose sandy soils tend to have low shear strength; thus, improving the mechanical properties is necessary to enhance the bond of soil grains. Adding an additive that will form a bonding agent, i.e., calcite, within the soil to increase the strength of the soil is a relatively novel technique. Soybean Crude Urease Calcite Precipitation (SCU-CP) is a soil improvement method that utilizes soybeans as a catalyst for calcite formation in the reaction of urea and CaCl2. This study aims to evaluate the efficacy of SCU-CP in the large-scale application in terms of the distribution of calcite and its impact on the behavior of the California Bearing Ratio. A soil sample made with a 1-m acrylic mold with a 5cm diameter and a drum test with a height and diameters of 50 cm and 60 cm, respectively. The results in a percentage distribution of material vertically on a 1-m acrylic mold and horizontally on a 60 cm diameter drum with an even distribution. The average percent spread is 3.96% in the mold and 7.19% in the drum-test even distribution of strength, where the average CBR result is 1.40 on the seventh day. This study concluded that the SCU-CP method with the pouring technique has a promising approach for real-field application.