Why Joint Edges Break And Force Concrete Joint Repair
The damage that brings us in for concrete joint repair is mechanical, and it starts at the gap.
A saw cut control joint leaves the concrete shoulder each side of it unsupported. A hard wheeled forklift drops into the gap and strikes the opposite edge, thousands of times a week. Slabs shrink as they cure and dry, so the gap widens year on year and the impact grows with it. Once a shoulder begins to break, the trench that forms holds water and cleaner and accelerates everything from there.
Smaller, harder wheels and heavier loads in modern distribution buildings have made this worse rather than better, which is why the specifications have been tightened over the last decade. The newer buildings going up on Griffin Way and Woodall Way in Woodstock run exactly that kind of equipment.
Concrete Joint Repair Uses A Filler, Not A Sealant
These two products are confused constantly, and the consequences of confusing them land on the floor as concrete joint repair work.
Sealants are soft and flexible, made to flex and shed water, which is precisely what an external expansion joint calls for. Concrete joint repair filler is the opposite: stiff, taken right down the cut, shaved level, and structural in purpose. It props the shoulder so wheel loads travel over the joint rather than hammering into its edge.
The American Concrete Institute recommends a semi rigid epoxy or polyurea filler at Shore A80 or harder for trafficked floors, and newer guidance pushes that figure higher. The working rule for concrete joint repair is that the filler should be at least as hard as the wheels crossing it. Products in common use run around A90 to A95. A soft sealant in an interior control joint supports nothing whatsoever, and it is the most common reason we are called out at all.
Concrete Joint Repair Where The Shoulder Has Already Gone
Where the edge has already broken away, concrete joint repair means more than simply filling the joint.
The broken concrete is saw cut back to sound material, the area is cleaned out, the shoulder is rebuilt with a repair mortar chosen for the traffic, and the joint is then refilled to full depth. Done properly, the repaired edge carries traffic as well as the original concrete did. Polyurea fillers take traffic again quickly, which is what lets concrete joint repair fit inside a short overnight window.
