Performance of clay–epoxy interface at different points on proctor curve

Different coating materials are applied at the soil-structure interface to enhance the interfacial performance between soil and the structure. The primary objective of this work was to investigate the mechanism behind the interfacial adhesive strength between epoxy coating and soil. Soil can exhibit different pore microstructures upon variation in its moisture content. This can potentially affect the soil-polymer coating interface performance. Compacted soils at different water contents on the proctor curve were considered and its porosity was estimated applying Mercury Intrusion Porosimetry (MIP). Load-displacement responses from macro-mechanical tests showed a highest interfacial strength not at the optimum moinsture content, however,at the dry of optimum. Results had indicated that the major contributions to the interfacial strengths arises from the plastic deformation of epoxy which penetrates through clay surface pores. In addition, the physical work of adhesion at the interface arising from the electron donor oxygen sites at the clay siloxane surface and epoxy functional groups were considered to affect the initial pre-peak stage of the load-displacement characteristics.