cementbentonit

Cement-bentonite is a geotechnical material composed of Portland cement and bentonite clay, used primarily as a grout or backfill to create impermeable barriers in soil and rock. When mixed with water, the cement hydrates to gain strength, while the bentonite swells to reduce permeability. The resulting material can be pumped into trenches, boreholes, or between soil strata and then set in place to form a low-permeability curtain.

The cement-bentonite mixture is designed to balance flowability for emplacement with long-term strength and impermeability. Bentonite provides swelling and sealing properties that limit fluid transmission, while cement contributes early strength and durability. Mix designs vary by project and system, and admixtures may be added to control setting time, shrinkage, and rheology. The material is typically used as a slurry or grout, and can be placed as part of slurry walls, cut-off walls, or seepage barriers in excavation support, tunneling, dam construction, and mining operations.

Common applications include groundwater cut-off in construction sites, support of excavations in urban or sensitive environments, sealing around shafts and tunnels, and stabilization of soil against seepage and water pressure. Cement-bentonite barriers are valued for their relatively low permeability, compatibility with a range of soils, and ability to be constructed in challenging conditions.

Limitations include potential shrinkage cracking if curing is inadequate, sensitivity to temperature and groundwater chemistry, and the need for proper mixing and placement to avoid segregation. Long-term performance depends on proper design, quality control, and ongoing monitoring. See also grout curtains, slurry walls, bentonite, and cement-based stabilizers.