Swelling properties of natural and modified bentonites by rheological description

摘要

Bentonite is used for landfill application because of its high sealing ability. Following the swelling phenomenon the water reacts with the bentonite and expands the solid particles. The voids are filled and this reduces permeability of the soil. However, the drawback is the long time needed to assess the hydraulic performance, whereas the engineers require simple and rapid characterization parameters to design the hydraulic barrier. Present paper investigates the possibility of use of rheology testing to describe the swelling properties of bentonite used for geotechnical engineering issues. Rheology testing is proposed to investigate the swelling properties of different nature of bentonite. Different types of bentonite are tested: natural sodium, natural calcium and sodium-activated calcium bentonites. Rheological measurements are performed in steady and dynamic conditions. Free swell and oedometer swell tests are also performed and compared.