Cement-Bentonite in comparison with other Cemented Materials

The deformation behaviour of cement-bentonite (CB) materials used in low permeability cut-off walls is critical to the performance of these barriers in situ. Whilst a number of investigation have focused on the deformation behaviour of CB materials, it is suggested that insufficient knowledge has been generated to allow for the determination of the behaviour of a CB wall in situ with confidence. This paper reviews the deformation behaviour of other cemented particulate systems commonly encountered in civil engineering: concrete, rock, clays and cemented soils, and compares them with CB response to determine if the greater research effort associated with these materials could be used to improve understanding of CB. It is concluded a direct comparison of physical behaviour between these materials is problematic due to the differences observed. Furthermore, the formation of mircocracks prior to reaching the peak strength in cemented materials (rocks, etc.) is an area that does not appear to been studied previously with CB materials; yet microcrack formation could have a significant impact on the CB ability to retard groundwater migration. Therefore, additional research is required into CB behaviour, prior to achievement of the peak strength, to determine if microcracking in CB is a significant hazard.