Combined Effects Of Coir Fiber And MICP On The Mechanical Properties Of Loose Fine Sand

Abstract

In recent years, there has been a notable surge in interest surrounding the technique known as microbial-induced calcium carbonate precipitation (MICP), which is being recognized as a promising and eco-friendly method for improving soil conditions. A laboratory experiment was conducted to investigate the influence of incorporating randomly distributed non-continuous Coir fibers on the stress-strain characteristics of soil treated with Microbial-induced Calcium carbonate Precipitation catalysed by bacteria. In geotechnical engineering, the direct shear test is a widely utilized laboratory procedure to assess the shear strength characteristics of soil or sand materials. The specimens were prepared in a highly unconsolidated form, with a relative density ranging from 14% to 18%. The preparation involved using flexible moulds that allowed for complete contact. Five various aspect ratio’s (45, 90, 136, 182, and 227) and fiber contents (0.1, 0.2, 0.3, 0.4, and 0.5% by weight of sand) were employed in the preparation process. The Direct Shear Tests performed on both fiber-reinforced fine sand and bio-cemented fiber-reinforced fine sand. The findings indicated that the inclusion of fibers led to enhancements in ductility and failure strain. The stress-strain curves demonstrate that the presence of fiber inclusions induces a transition in the failure behavior of bio-cemented soil from brittle to ductile modes. The shear modulus exhibits an initial decrease followed by a subsequent increase, reaching its maximum value at an optimal aspect ratio of 182.