`Stabilization of silty clay through fungal-induced calcite precipitation

Abstract

Research studies show that fungal-based microbial-induced calcite precipitation (MICP) extensively enhances the strength behaviour of concrete materials. However, fungal-based MICP's effectiveness in silty clay has not been investigated yet. This study examines fungalbased MICP's influences in stabilisation of silty clay during wetting and drying cycles. The Fusarium oxysporum fungal inoculum, in combination with a calcium chloride cementitious solution, was used to stabilise the soil. The laboratory tests, including Atterberg limits, unconfined compressive strength (UCS), specific gravity, X-ray diffraction (XRD), scanning electron microscopy (SEM), etc., were carried out to attain the study objectives. The test results show that the soil specimens treated with 0.25 M cementitious solution in combination with fungal inoculum provide peak strength. The soil strength reduces from 2549.20 to 1108 kPa giving 130.07% decrease between 1st and 9 th wetting and drying cycles, Comparatively, the strength of untreated soil changes from 1215.40 to 429.70 kPa,showing a reduction of 182.85% between 1 st and 7 th cycle. The untreated samples of soil show less stability than the treated soil and collapsed after the 7 th cycle. The study findings conclude that the fungal-based MICP technique can effectively strengthen the clayey soil due to changes in the structure of treated soil.