A Kansas Department of Transportation (KDOT) bridge resurfacing project here - using Unitex epoxy - will cover about 1.76 million sq. ft. when complete. That's 14.4 lane-miles or nearly 40 acres. The resurfacing is expected to cut bridge maintenance costs and repairs while providing a safer driving surface.
More than halfway complete, it's believed to be the biggest polymer bridge-resurfacing project ever tackled in the U.S.
The Unitex Type III DOT epoxy used on the project has undergone extensive lab and field-testing by the U.S. Army Corps of Engineers, KDOT and many other state and federal agencies.
Why epoxy? Polymer is lighter, more flexible and weather and corrosion resistant than resurfacing with concrete. Bridges resurfaced with Unitex Type III DOT epoxy can reduce lifecycle costs, saving local and state governments taxpayer dollars for bridge maintenance.
Resurfacing using the overnight-curing epoxy overlay has an added, and significant, benefit during the work itself. It can cure overnight, instead of several days. So local motorists using the I-135 expressway here don't see lanes closing until 7 p.m. One lane is open all night. All are open to traffic again the next morning.
"We believe using an epoxy overlay can help save Kansas taxpayers dollars because research shows that repairs made with this material are quicker, less costly, weigh less and are more waterproof than those using concrete," says Dave Meggers, KDOT research development engineer.
"Unitex's Type III DOT epoxy overlay prevents future salt damage to the concrete and rebar," says Unitex president John Grissinger. "It seals the deck from de-icing salts and allows the concrete underneath to dry."
Compared to using concrete for repairing bridge surfaces, the Unitex epoxy overlay system reduces weight added to the structure by more than 50 percent.
And it's virtually impervious to road salt. Concrete deteriorates when de- icing salts and moisture reach the reinforcing steel in the concrete - causing it to corrode and break the concrete.
To keep I-135 open to traffic during the day, crews from Wildcat Construction repair the 2.4 mile elevated portion of the expressway in two steps. First, the surface is prepared with shot blasting to create a clean, roughened profile to which the epoxy overlay bonds. The flexible Unitex epoxy is applied to the roughened surface and serves as a high-strength binder for aggregate, which is applied onto the epoxy. Then, the second and final layer of the Unitex flexible epoxy is applied and aggregate is added, creating a new wearing surface. The roadway reopens in early morning.
Unitex develops products that not only cure faster than concrete, but also are lighter, better bonding and make the bridge deck more resistant to corrosion than the typical concrete overlay.