First Application of UHPC Bridge Deck Overlay in North America

Deterioration of existing bridge decks, which usually originates with the deck cracking on the top surface, is a common problem in North America. It causes frequent repair of the decks to limit further damage resulting from water/chloride ingress. Superior engineering and durability properties facilitate the use of ultra-high performance concrete (UHPC) as an attractive alternative for a deck overlay, minimizing both deck deterioration and maintenance costs. Recently developed UHPC thixotropic mix designs, which are different from commonly used self-leveling UHPC, enable UHPC overlay to be used on decks with slopes and meet specific crowning requirements. The use of a UHPC thixotropic mix design with 3.25% of steel fibers was successfully evaluated under laboratory conditions by applying it on sloping deck surfaces with appropriate roughness between the normal concrete (NC) and UHPC. The feasibility of applying this technology in the field was then investigated on a small bridge for the first time in North America in May 2016. This paper presents the details about the laboratory evaluation, field implementation of UHPC overlay, and lessons learned from this first UHPC overlay project in North America.

Test Research and Simulation Analysis about ECO-ECC Materials Repairing Concrete Beams

In the actual project, ECO-ECC can be used in repairing bridge deck overlay, prefabricated lightweight partitions, structural coupling beams and slab reinforcement[1][2]. The use of fiber-reinforced composite materials ECO-ECC can implement outside paste reinforcement in damaged components [3][4], supplemented by appropriate construction methods (such as jet ECC process). The high liquidity of ECO-ECC, coupled with high decentralization of micro-fiber can solve the problem of old and new concrete interface bonding and restore the using functionality and security of the structure, and extend the use life. The maximum principal stress of PC, E70, E80 and E90 is 130με, 501με, 257με and 168με. The area of maximum principal stress decreases with the thickness of strengthening layer reduces. That explains that strengthening layer provide better ductility to prevent brittle failure.