Suitability of Rice Husk Ash (RHA) with lime as a soil stabilizer in geotechnical applications

Soils containing significant levels of silt or clay generally exhibit unacceptable engineering properties (i.e. low strength, high compressibility and high level of volumetric changes) when exposed to variation in moisture content. Chemical stabilizers such as cement and lime which are currently practiced, are often high-priced and unhygienic in terms of environmental sustainability. The prevailing study intended to explore the potential of the local Rice Husk Ash (RHA) which is an agricultural waste, with lime as a soil stabilizer. This experimental study was conducted on clayey soil with high plasticity. Different mixture proportions of RHA (i.e. 5%, 10%, 20% and 30%) and lime (i.e. 10% and 20%) were used to treat the parent soil. Observations were made for variations in index (i.e. liquid limit, plastic limit, sieve analysis, etc.) and mechanical properties (i.e. compressibility, permeability and shear strength) of treated soils soon and 28 days after mixing. It was found that 10% of RHA and 20% of lime by dry soil weight as the optimum dosage for the treatment. This optimum dosage increases the unconfined compressive strength and internal friction angle by 54.05% and 60.48%, respectively and reduces plasticity index by 56.67% at 28 days after mixing. It could be identified that RHA and lime mixture was capable of improving index and mechanical properties of soil, positively.