Bridge Expansion Joint for Bridges with Expansion Joints in Epoxy Overlays

Epoxy asphalt and polymer concrete overlays on bridge decks are more brittle than conventional asphalt overlays and are more susceptible to cracking at expansion joint locations. The joint design must minimize the stress concentration at the overlay-joint interface to prevent premature cracking. Epoxy asphalt properties that affect joint design include the higher stiffness and lower flexibility compared to conventional asphalt. The higher stiffness means that epoxy asphalt is less able to accommodate the movement of the joint without cracking. The joint must be designed to minimize the stress concentration at the overlay-joint interface. Polymer concrete properties that affect joint design include the very high stiffness and the brittle failure mode. Polymer concrete cracks suddenly without warning, unlike conventional asphalt which deforms gradually. The joint must be designed to prevent any stress concentration that could initiate cracking. Joint recess design for epoxy and polymer concrete overlays uses a recessed joint that is installed below the overlay surface. The overlay is applied over the joint, and the joint is then cut through the overlay to create the expansion gap. This approach eliminates the stress concentration at the overlay-joint interface. Saw-cut joint design for epoxy and polymer concrete overlays uses a saw cut through the overlay at the joint location to create a clean, straight expansion gap. The saw cut must be made after the overlay has cured to the required strength. The saw cut is then filled with a flexible sealant that accommodates the movement of the joint. Maintenance of epoxy and polymer concrete overlay expansion joints requires annual inspection for cracking and debonding. Any cracks in the overlay at the joint location must be sealed promptly to prevent water infiltration. Significant cracking requires removal and replacement of the overlay at the joint location.