Formulation of Bentonite-Cement Grout for Sealing Walls

Marine and land environment is deeply affected by NPK company phosphogypsum storage in Sfax city. A part of Taparura project aims to confine this pile of partially or totally heavy metal pollution by creating a sealing wall released by a material made of bentonite and cement waterproof. This study focuses on a methodology for formulating a cement bentonite grout to construct the screen. First, a synthesis bibliography introduces the bentonite and cement properties material composition as well as the methods of formulation and standardized tests. Second, an experimental study was carried out to formulate the cement bentonite material. The physical properties of fresh and hardened material as well as its mechanical properties were determined. This experimental approach has permitted the determination of B/W B , B/C and W T /C ratios of the BC grout and the strength properties of the projected grout. Moreover, the properties of grout in fresh state of bentonite cement are in a good correlation with the desired conditions for the screen execution. The vertical permeability obtained is so low which limits greatly the flows through the screen. The Young modulus of cement bentonite material is near the soil modulus which conducts to the same strains in both soil and screen thereby reducing micro cracks in screen.