In the waterproofing of underground structures subject to constant hydrostatic pressure (tanks, pipes, swimming pools, etc.) faults and problems may arise in the pump systems, open screen joints, exposed aggregate concrete areas, storage tanks, full swimming pools, tunnels, flooded lift shafts, under road parking roofs, etc. requiring the immediate plugging of leaks, or as an essential first step in repair work, which can be difficult using traditional mortar.
Single component expansive polyurethane resins are especially useful in such situations. These, once injected, react with the water (including sea water and other types with a pH of between 4 and 10) and will polymerize and expand up to 35 times their original volume, forming hydrophobic foam, which is totally waterproof and generate an expansion pressure close to 3N/mm2, capable of displacing the water from holes and fissures.
These types of resin are available in rigid and flexible versions, which should be selected according to the type of structure and behaviour. The flexible versions are recommended for joins or fissures which involve movement, as their viscosity is greater than the rigid ones, negatively affecting their penetration and therefore sealing capacity.
RIGID RESINS and FLEXIBLE RESINS
Instant leak filling systems based on state of the art single component polyurethane injection resins, with excellent (waterproof) sealing properties and cutting power.
These are resins which during the injection process and on contact with water react to abruptly generate, on drying, a rigid polyurethane foam, which is hard, closed cell and fully resistant to the passage of water.
These systems are complementary to the cement systems, allowing the filling of hypothetical leaks, to subsequently apply the cement based systems (crystallizing/flexible) without the risk of being washed by the former before their correct drying process is complete.