CJGeo specializes in using polyurethane grouting to stabilize and lift settled or unstable concrete slabs and structures.
Polyurethane grouting was developed in Europe in the 1970s as an alternative to cement-based pressure grouting. The principal of polyurethane grouting is effectively the same as cement pressure grouting–injecting material below concrete can be used to push the concrete up. Polyurethane grouting differs from mud jacking in that the expansion of the polyurethane foam is what generates lift, as opposed to the mechanical force of the pump.
CJGrout is our line of geotechnical polyurethane grouts. Based on our experience placing millions of pounds of polyurethane grout in applications ranging from highway undersealing to foundation lifting and tunnel leak sealing, we have developed grouts specially formulated for the unique challenges of the geotechnical and utility markets. CJGrout polyurethanes are manufactured by NCFI, a market leader in plural component polyurethanes.
Concrete lifting using polyurethane grouts can be used to correct settlement in two ways. The most common method is injecting grout immediately below or adjacent to the slab or structure. Shallow grouting is sufficient in applications where the underlying soils are stable, or the consequences of resettlement are low. If a higher factor of safety is required, or if the underlying soils are known to be inadequate, grout can also be injected into the adjacent soils. Polyurethane grouting in soils behaves just like compaction grouting using low mobility grouts.
Polyurethane grouting in soils is coupled with DCP (Dynamic Cone Penetrometer) testing to quantify the conditions of existing soil before and after polyurethane grouting. Depending on the conditions encountered during DCP testing, grout planning is done prior to injection to achieve target results.