Dowel bar retrofit

It is a technique which several U.S. states' departments of transportation have successfully used in repairs to address faulting in older jointed plain concrete pavements.

Following dowel placement the slots are then typically backfilled with a non-shrink concrete mixture, and the pavement is diamond-ground to restore smoothness.

On older highways built in the early-to-mid 20th century, dowel bars (steel rods) were placed across the joints to help transfer the load from one panel to the next.

Dowel Bar Retrofit has been proven to outlast Asphalt Overlay by at least ten years, and significantly improves ride quality.

The dowels need to be smooth, round, epoxy and made of bond breaker coated steel conforming to requirements.

The foam core insert is used to re-establish the joint or crack, which allows the bar within each side of the slot to expand and contract.

Saw slots parallel to each other and to the center line of the roadway with a maximum tolerance of 1⁄4-inch per 12 inches of dowel bar length.

Employ saws equipped with gang-mounted diamond blades capable of cutting three or four slots simultaneously in each wheel path.

Remove water and paste residue from the pavement surface immediately by means of a vacuum attachment on the sawing machine.

During concrete removal operations, use a small bush hammer as necessary to produce a flat, level surface within the slot so the backfill flows and consolidates under the dowel bars.

Finally, diamond-grind the pavement surface within 30 working days of dowel bar retrofit placement.

[3] The backfilled slots may sometime give an impression that the highway pavements have been milled into grooves especially after the wear of patching material caused by studded tires.