Single-layer waterproofing membrane based on sodium bentonite, a natural clay mineral that is woven into a geotextile carrier fabric as granules or needled with it. The bentonite membrane has a sealing effect on the side of a basement component made of reinforced concrete that is in contact with the ground, without an additional sealing membrane made of plastic.
Fresh concrete composite with the reinforced concrete component creates a close connection between the component and the waterproofing membrane, which excludes backward flow after activation of the bentonite. Activation only takes place when the granules come into contact with moisture. Due to the resulting swelling pressure in the material, the waterproofing membrane seals towards the concrete with simultaneous contact pressure (e.g. due to soil or additional load). The state of hydration of the gel-like bentonite layer persists even if the environment dries out. Bentonite seals were developed in particular for water loads from accumulating seepage water and pressing groundwater. While this technology has been anchored in earthworks, landfills and civil engineering for decades, it has only been used in the field of ground-contact building waterproofing for a few years as a so-called brown tank.
Source: bauwion
