Exploring the potential of charred bagasse as an eco-friendly material for soil stabilization

The burning of sugarcane bagasse in agricultural-rich countries has been a source of air pollution contributing to smog largely and raising the air quality index to alarming levels. Use of charred bagasse as an amendment material for highly plastic clay lies at the juncture of the reuse of waste material and carbon sequestration. The current study focuses on the use of bagasse biochar for the stabilization of soft soil as a carbon-neutral material. Bagasse biochar was added to the soil in varying proportions of 0, 2, 4, 6, 8, 10, and 12 % to determine its effects on the strength, deformation, and durability characteristics. A series of tests of consistency limits, unconfined compression tests, and swell potential tests were conducted using the above percentages. An addition of 10 % biochar was found to be optimal in reducing the overall plasticity index and swell shrinkage properties of soil whereas it increased the unconfined compressive strength (UCS) of soil from 300 kPa to 709 kPa. Fourier transform infrared spectroscopy (FTIR) tests confirmed the integration of amendment material in the soil mass. X-ray diffraction (XRD) and Scanning electron microscopy (SEM) techniques indicated the reduction of inter-pore-lattice of soil aggregates creating macro-aggregation due to the hydrophilic nature of biochar employed. Study signifies that practical applications of charred bagasse in soil stabilization can not only improve the strength and expansion-contraction phenomenon of expansive soil but it can also reduce the disposal of bagasse waste. • Consistency limits modification generated positive results with charred bagasse inclusion in highly plastic clay. • The unconfined compressive strength of expansive soil increased by 2.36 times at 10 % optimal blend. • Swelling potential declined by 73 % with bagasse biochar addition. • FTIR, XRD and SEM confirmed the reduction of swelling minerals and formation of biochar-coated clay matrix.