Problem:  A void was discovered under a concrete roadway during an open cut duct bank installation.

Special Considerations:  Due to being on a military base, absolute minimal downtime was essential.  The exact size of void was unknown until the day of work, so the ability to be prepared to pump any volume of material was crucial.

Process:  Concrete Jack's crew used compressed air to clean loose material from the temporary trench backfill out of the void space.  Afterward cleaning loose material out of the void, Concrete Jack's foam jacking crew injected high density polyurethane foam into the void using a free spray method.  The foam traveled throughout the voids under the slab as a liquid and then expanded to completely fill under the unsupported concrete.

Lasting Results:  Concrete Jack was able to fill the void in less than two hours, from start to finish, including on-site set up, void cleaning, installation and clean up.  The void filling was achieved without affecting the elevation of the roadway, which was an important requirement.  Afterwards, the area was immediately ready for installation of the trench backfill material and subsequent paving and vehicular traffic.