This article first appeared in the FHWA’s EDC News Weekly Newsletter of April 29th, 2021 and featured how NJDOT has applied UHPC for bridge preservation and repair.
In the final week, we’ll highlight the New Jersey Department of Transportation (NJDOT), which has recently used UHPC in multiple projects for bridge P&R.
NJDOT was familiar with the benefits of UHPC compared to conventional concrete through its use in field cast connections for precast bridge decks for re-decking projects. NJDOT had been looking for a new overlay preservation system for aging bridge decks that would enhance and extend the service life of their existing structures. However, the NJDOT had not used UHPC as a bridge deck overlay. NJDOT decided to install three UHPC bridge deck overlays as part of a research project contract. One of these projects, which was completed on a bridge spanning the Newark Turnpike, included both a UHPC bridge deck overlay and field-cast UHPC joint headers.
This curved 3-span bridge, originally built in 1979, feeds nearly 30,000 vehicles per day from the New Jersey Turnpike onto I–280. The heavy traffic and the impact of de-icing salts resulted in corrosion of the reinforcing steel in the existing bridge deck, as well as the deterioration of all abutment and pier expansion joints.
Prior to installation of the UHPC overlay and field cast UHPC headers, the existing asphalt overlay was removed, as were the deteriorated expansion joints. A new UHPC header expansion joint solution was installed, and after installation the finished UHPC overlay was covered with asphalt. The resulting 340-foot UHPC overlay is currently the longest continuous overlay installation in North America.
The overlay and the other two installations included in the project showed that preserving bridge decks with a UHPC overlay will provide NJDOT with durable, long-lasting bridge decks and will extend the service life of the structures. Additionally, the bridge overlays showed that UHPC overlay construction methods can minimize traffic interruptions and shorten the total construction time.