Bentonite slurry is a combination of sodium bentonite and slurry. A slurry is a thin sloppy mud or cement or, in extended use, any fluid mixture of a pulverized solid with water, often used as a convenient way of handling solids in bulk. This combination is frequently utilized to form a solid protective barrier in the ground.

This also finds its application in the construction of special foundations for digging diaphragm walls and bored piles. Bentonite is implemented for self-hardening mixtures which are then resorted to build cut off walls, grouting mortars, and grouting. Finally, bentonite waterproofing properties are best exploited in environmental engineering, to seal off soil infiltrations, and line the base of landfills.