Cementitious concrete bridge deck overlays (LMC, HPC, MMC) are failing by delamination faster than ever before. Many states are struggling to find a solution as failures grow, while budgets shrink. Although the New Jersey Department of Transportation has historically followed a “bare deck” philosophy, they were experiencing problems and recognized the need for an effective solution. The state of New Jersey has the highest population density in the nation and this is reflected in their traffic congestion. The NJ DOT cannot restrict traffic for extended periods or fix the same location more than once. They needed to find a solution that met very stringent requirements. The replacement material could not crack and delaminate like the Latex Modified Concrete that was becoming a growing problem. It would need to be more resilient than cementitious concrete to avoid rutting or loss of friction. The replacement material would also have to cure very rapidly in cold nighttime conditions to have the lane opened to traffic without any disruption for morning commuters. New Jersey DOT structures engineers turned to Kwik Bond Polymers’ PPC1121 Polyester Polymer Concrete.
SCOPE OF WORK
The Department already had experience with Polyester Polymer Concrete for various applications, but decided to put it to the test for the replacement of failing LMC on a larger scale. They chose to replace an entire lane of failed LMC on a bridge on I-80 Eastbound, about 30 minutes from Manhattan. The work would be completed on a nightly basis over the course of a short week. Each shift would include removal of LMC, sounding and patching of the substrate deck, and placement of Polyester Polymer Concrete to match the grade of the adjacent lanes. If everything went well, the morning rush of commuters would notice that the bridge had a smoother ride without ever knowing what took place the night before. The LMC overlay removal was completed with standard jackhammers, with care taken to only remove the overlay concrete. PPC features an integral bond to the substrate through the use of a high molecular weight methacrylate healer/sealer primer, so there is no need to remove sound deck concrete. The composite action between the substrate concrete and the PPC system means the new overlay will stay bonded to the substrate for the life of the deck without requiring rebar exposure. Some of the substrate deck was removed and replaced with PPC as it was unsound after being exposed to chloride and moisture through cracks in the LMC overlay. The PPC was mixed in basic mortar mixers and finished with a screed, all methods similar to standard concrete. The surface was tined for long lasting skid resistance. After less than two hours of cure time, the lane closure was removed and all lanes of I-80 were open to traffic, on time, every night.
After the success of the I-80 LMC replacement project, New Jersey DOT has used PPC 1121 in multiple locations with the same issue of failing LMC overlays. The PPC has a 100% success rate. Between the composite action of the integral bond, rapid cure time, and 30 year history of success, Kwik Bond Polymers’ PPC 1121 Polyester Polymer Concrete is the best solution to a common problem with today’s infrastructure.