Selection Of Chemical Grouts

Beijing Langwei uses chemical grouts for stopping leaks in a variety of structures. By analysing the structure type and the size of the leak, we can then determine which product and process works best for the given problem.

With weeping or small leaks, a major focus is on the viscosity, or thickness, of the resin. Low viscosity resins can easily penetrate the cracks and ensure that all cracked areas are repaired.

Hydrophilic chemical grouts are attracted to water and ‘chase moisture.’ In doing so, the grout follows all paths along the crack in order to reach and seal the leaks. For purposes of sealing leaks with chemical grouts, a hairline crack is considered one that is 1.6mm or less. Several products are independently verified to meet the standard for contact with potable water, making them ideal for water treatment, transport and storage structures.

With gushing or large leaks, quick reaction or ‘set’ times are important. This ensures that the resin has the opportunity to react with the water currently present and expand quickly enough to form a watertight, rigid foam before the leak can wash grout away. Set times can be controlled by catalysts or activators. Where hydrostatic pressures are high, a hydraulic cement patching material or oakum can be used to stop or slow the flow enough for the chemical grout to react.

Equally important is the expansion rate. Gushing leaks are caused by larger flows of water, meaning that a large area would need to be sealed in order to stop the leak. Using products with higher expansion rates allows for greater coverage of the void area. In below-grade structures, the large expansion rate also serves to fill any voids behind the structure and thus forms a curtain that serves as a 360-degree shield.

Our company selects products which have the necessary properties to repair the leak in the particular application. Such materials include products with the following properties:

Acrylate, very low viscosity, low toxicity, elastomeric gel, for crack injection in structures

Acrylate, very low viscosity, low toxicity, elastomeric gel, primarily for geotechnical applications, compliant for potable water use

Hydrophilic, polyurethane, single-component, extra low viscosity, compliant for potable water use

Hydrophilic, polyurethane, medium viscosity, single-component, for medium to wide cracks

Hydrophobic, polyurethane, low viscosity, variable set time, compliant for potable water use

Rapid cure polyurea non-sag paste for temporary surface seal prior to crack injection of epoxy or polyurethane grouts. Can be peeled off, leaving a clean surface.

Acrylate, very low viscosity, low toxicity, elastomeric gel, certified for potable water use, primarily for geotechnical applications.

Hydrophilic, polyurethane, extra low viscosity, single-component, compliant for potable water use

Hydrophobic, polyurethane, low viscosity, variable set time, compliant for potable water use

Hydrophobic, polyurethane, variable set time, highly expansive foam, compliant for potable water use

Cement product to stop water flow prior to crack injection