Cement-bentonite in comparison with other cemented materials

Abstract

The deformation behaviour of cement-bentonite (CB) materials used in low-permeability cut-off walls is critical to the performance of these barriers on site. While a number of investigations 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 on site 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 it 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 that a direct comparison of physical behaviour between these materials is problematic due to the differences observed. Furthermore, formation of microcracks before the peak strength in cemented materials (rocks, etc.) is an area that does not appear to have been studied previously with CB materials; yet it could have a significant impact on the ability of a CB barrier to retard groundwater migration. Therefore, additional research is required on CB behaviour, prior to the achievement of the peak strength, to determine whether microcracking in CB is a significant hazard.