Desiccation crack in lime-treated silty clay: Experimental evaluation and constitutive interpretation

The present work investigates the desiccation effects on a lime-treated clayey silt. Original experimental techniques have been developed to control suction conditions (with osmotic technique) and to track volume variations and cracks occurrence upon drying. Free and constrained dryings are performed to evaluate the shrinkage potential (for free drying) and the conditions of desiccation crack triggering (upon constrained drying). Also, indirect tensile tests and uniaxial compression tests are carried out to evaluate the strength at various suctions. Those investigations have been performed on natural and lime-treated clayey silt in order to emphasis the role of the lime treatment in the triggering and/or mitigation of the cracking process. At the end, generalized effective stress framework with an effective stress parameter calibrated according to a power law is used to provide a constitutive interpretation of the occurrence of desiccation cracks in relation with the water retention properties, the soil stiffness, the tensile strength and the geometrical constraints of the soil samples. For the used compacted materials, it is demonstrated that the lime treatment postpones the occurrence of desiccation cracks and so, plays a favourable role in the stabilization of soft soils subject to drying.