There is an increasing worldwide demand for slurry walls to contain contaminated groundwater. Lateritic soils, due to their wide distribution in the Brazilian territory, have great potential to be used in these cases. However, some issues remain uncertain and need investigation, including the interaction and compatibility of these soils with bentonite or cement, the most used additives to improve their geotechnical properties. This work evaluates some mechanical and hydraulic properties of a lateritic soil sample and its mixtures with bentonite and cement. The laboratorial procedures consisted of physical, physico-chemical and mineralogical characterization, hydraulic conductivity, uniaxial compression and direct shearing testing. The results demonstrate that the addition of 3% of bentonite in compacted samples did not decrease the hydraulic conductivity of the lateric soil as expected. On the other hand, the addition of cement has led to a 100-fold increase in this parameter, in spite of the substantial increase in the shear strength caused by the mixture.
Slurry cutoff walls; bentonite; cement; backfill; hydraulic conductivity
