Precast concrete bridge deck panels and precast concrete deck-bulb-tee girders both present solutions capable of facilitating accelerated construction/reconstruction/rehabilitation of highway bridges. However, the connections between these elements, which must be completed in the field, have proved to be a hurdle to successful implementation. In short, the connections between elements present long-term durability concerns and often result in less than desirable performance of the system as a whole. Ultra-High Performance Concrete (UHPC) is a type of advanced cementitious material that is particularly well suited to highway bridge applications due to its enhanced durability and increased strengths as compared to conventional concretes. UHPC has the potential to work particularly well in connection details between precast elements due to its ability to develop mild steel reinforcement over short distances allowing for the design of minimal width cast-in-place joints which do not require post-tensioning or complex embedments. New York State DOT (NYSDOT) is particularly interested in this concept and is completing two bridge rehabilitation projects during the summer of 2009 which implement the cast-in-place UHPC connection. NYSDOT has partnered with FHWA to investigate the performance of the cast-in-place UHPC connection detail through full-scale structural testing at the Turner-Fairbank Highway Research Center.

The objective of this study is to investigate the structural performance of ultra-high performance concrete (UHPC) connection details developed for implementation in precast concrete bridge deck systems.

The study includes the cyclic and static loading of six full-scale precast bridge deck panels each containing a cast-in-place UHPC connection detail. Each specimen will be loaded cyclically under simulated truck wheel loading for at least 4 million cycles. The performance of the connection will be monitored throughout the cycling to capture any changes in structural performance or any cracking which can lead to future environmental durability concerns. After the cyclic testing is complete, each panel will be loaded statically to failure to investigate the ultimate capacity of the connection detail. Four of the six test specimens will simulate 8-inch thick precast deck panels while the remaining two will simulate 6-inch thick top flanges on deck-bulb-tee girders. Other variables being investigated in the study include mild steel reinforcement type (hairpin, headed, straight) and mild steel reinforcement coating (black, galvanized, epoxy). The test specimens have been fabricated and the testing will begin in the summer of 2009.