Why Forklift Wheels Break Joint Edges And Force Concrete Joint Repair
A saw cut leaves two unsupported concrete edges facing each other across a gap. A hard wheeled forklift or a pallet jack crossing that gap lands an impact load on an edge with nothing beneath it to react against.
Left without concrete joint repair for long enough, the edge micro fractures, the fracture spreads back into the slab, and a piece breaks away. That is spalling, and it shows up as cracking and flaking within about four inches of the joint. Because it is caused by traffic rather than by age, it concentrates in the main aisles and at the ends of racking instead of spreading evenly across the building. That pattern is the diagnostic tell.
The gap then gets wider, the next wheel hits harder, and the damage accelerates. A joint left without repair does not stay the same, it gets worse at an increasing rate, and the concrete joint repair needed later is a bigger job than the one needed now.
Concrete Joint Repair Uses A Filler, Never A Sealant
This is the single most common concrete joint repair mistake we find on Halifax industrial floors. Somebody has run a soft grey caulk down the control joints, and it is why the edges are still breaking up.
A flexible sealant is designed to move and to keep water out. A joint filler in an interior control joint has a completely different job, which is to support the concrete shoulder and carry the wheel across the gap. To do that it has to be hard, it has to be installed full depth so it has a base to react against, and it has to be shaved flush with the floor so the wheel rolls across the joint instead of dropping into it.
Compressible backer rod belongs in an expansion joint and has no place in an interior control joint, because it removes the very support the filler needs.
If the material in your joints can be marked with a thumbnail, it is a sealant, and concrete joint repair with a semi rigid filler is the highest return work available on the floor.
Choosing Concrete Joint Repair Material: Epoxy Or Polyurea
Semi rigid epoxy is the harder and longer lasting of the two concrete joint repair materials, commonly giving seven to twelve years, and it tolerates a damp joint without gassing. The trade is time, because it needs eight to twelve hours before it can be shaved and taken back into service.
Polyurea is the shutdown material. It can be shaved after roughly half an hour and back under traffic inside the hour, and it can be installed in cold conditions epoxy will not tolerate, which matters in cold storage and in a Nova Scotia February. It typically gives five to ten years.
In a building that cannot stop, polyurea concrete joint repair is usually the answer. In a building with a real weekend window, epoxy is the better long term buy. Where the shoulders have already broken away, the joint is saw cut back to sound concrete, the shoulder is rebuilt in structural grout, the joint is re-cut through the new material and then filled. Spalls under about half an inch can be handled by the filler alone, and anything past an inch needs the shoulder rebuilt first.
