Bentonite, a type of clay primarily composed of montmorillonite, is used in cement and concrete for its unique properties, including high plasticity and swelling ability. It serves multiple roles, such as a water barrier, lubricant for drilling, and as a stabilizer in the concrete mix. In environments exposed to severe conditions—such as fluctuating moisture levels, heavy rains, and groundwater presence—bentonite’s swelling properties help in sealing cracks and joints in concrete, thereby enhancing the durability and waterproofing capabilities of construction materials.x