The polyurethane grout is injected under low pressure through or adjacent to a slab of foundation. The grout then expands to fill the crack or void. Many polyurethane grout techniques are available with variations in viscosity, reaction time, reaction with water, expansion characteristic and flexibility of the reacted grout. Polyurethane grouts can be single or multi-component, and can require a reactant or react when encountering water. It is important to select the correct grout for each application.
Polyurethane Injection is a re-leveling technique that raises concrete slabs and fills voids, using the regulated injection of lightweight, non-hazardous expanding polyurethane grout. When ground improvement is needed along with re-leveling, compaction grouting is performed first to densify deeper loose zones.
Then holes are drilled through the concrete slab or foundation for polyurethane grout to be injected to fill remaining voids and complete the lifting to final grade. After re-leveling, the drill holes are cleaned and filled with cement grout. The result is a densified subgrade, filled voids and a re-leveled and stabilized concrete slab.