Impact of agricultural waste on the shrink–swell behavior and cracking dynamics of expansive soils

Purpose The swelling characteristics and cracking of expansive clayey soils usually lead to their low yield, and as a result,large areas of expansive soils remain uncultivated and unproductive. There is a need for the development of simple, low-costtechnologies which will bring these soils into production. The amendment of expansive clayey soils with agricultural wasteproducts is a key goal for enhancing their production potential. Therefore, a study was conducted to evaluate the ameliorativeeffects of crop residues on the physiochemical and mechanical properties of expansive clayey soils.Method In this study, the potential soil amendments used include uncharred rice husk, rice husk biochar, uncharred sugarcanebagasse, and sugarcane bagasse biochar. The biochar was pyrolyzed at 450 °C. The amendments were applied intothe soil at four applications rates: 0, 2, 5, and 10% by weight of soil (w/w), respectively. The mixture was then incubated ina glasshouse for 280 days.Results Charred and uncharred rice husk and sugarcane bagasse improved the physico-mechanical properties related to soilexpansion. The liquid limit (LL), plastic limit (PL), plasticity (PI), coefficient of linier extensibility (COLEcore), volumetricshrinkage (VS), fissures’ dimensions, and crack area density (CAD) of the soil decreased with an increase in treatmentapplication rate. On the contrary, saturated water content increased with an increase in dosage.Conclusions 10% level of amendment application resulted in significantly improved soil properties than either 2% or 5%doses. Moreover, 2% level of amendment application is more preferable than 5% according to feasibility and economic pointof view.