Cementbentonite

Cement bentonite is a composite material used primarily in civil engineering applications, particularly for groundwater control and containment. It is created by mixing ordinary Portland cement, bentonite clay, and water. The precise proportions of these ingredients are critical and depend on the intended use. Bentonite is a clay mineral, typically montmorillonite, known for its ability to swell significantly when hydrated. This swelling property is key to the effectiveness of cement bentonite mixtures.

When water is added, the bentonite particles hydrate and expand, forming a gel-like substance. This gel drastically reduces the permeability of the mixture. The cement component hydrates and hardens, providing structural integrity and a solid matrix. The combined properties of low permeability and reasonable strength make cement bentonite a versatile material.

Common applications include slurry walls, cutoff trenches, and grouting. Slurry walls are used to create impermeable barriers in the ground to prevent groundwater flow or contain contaminants. Cutoff trenches are filled with cement bentonite to intercept and block groundwater movement. Grouting involves injecting the mixture into soil or rock fissures to seal them. The material's ability to remain plastic for a period before setting allows it to be placed in challenging underground conditions. Its relatively low cost and widespread availability of components also contribute to its popularity.