Slab Curl Repair

Repairing Slab Curl Inside Food Grade Manufacturing Facility, Roanoke, Virginia

Problem:

16,000 square feet of 6″ thick monolithic concrete slab floor with sawed joints curled.  Floor was in tunnel connecting a food grade container manufacturing facility and a food processing facility.  Robotic pallet movers traverse the tunnel, and were experiencing premature tire failure due to differential settlement and flexing at joints.

Constraints:

The slab curl repair and floor lifting work had to be completed during operations of the 24/7 facility.  Robotic pallet movers traversed the tunnel (two-way traffic) every 5 minutes during normal operations, and every 10 minutes during half-capacity sanitization days.  Slab curl repair had to be completed without disrupting the operations of the facility.

Solution:

High density polyurethane grouting to fill the voids under the slab which resulted from the slab curl.  Foam jacking was also used to correct the joints which had experienced differential settlement.  Foam jacking was chosen for the slab curl repair due to its rapid curing time (less than 30 seconds), which allowed for the continuous use of the floor, so operations were uninterrupted.

Results:

Two CJGeo polyurethane grouting crews injected geotechnical polyurethane under the slabs at the affected joints to stabilize the slabs for the slab curl repair.  The work was completed during a half-capacity day.  CJGeo workers stepped out of the way when the robotic pallet movers came through the work area.  All of the work was completed using dustless drilling, with food grade cleanliness.