Compacted Polymer-Enhanced Bentonite-Sand Mixture – Behaviour and Potential Applications

Abstract

An investigation into behaviour and potential applications of a polymer-enhanced bentonite-sand mixture (PEBSM) in its compacted state had been carried out in an environmental controlled laboratory. The experiments undertaken included microscopic visualization of the mixture, drying-wetting processes, consolidation and shear strength tests. The results obtained indicate that depending on the overburden pressure acting on the compacted mixture and its water content, settlement in combination with swelling and shrinkage may result in cracks or on contrary may close the initial cracks induced by the mechanical compaction in the field. The conclusions have been drawn based on an analytical assessment performed on the field and laboratory data gathered. A discussion is also brought up on the difference between two approaches used – single-valued effective stress and two-independent stress state variable approaches. The two approaches predict different values of suction at which crack starts to occur and different time-settlement behaviour.