Laboratory and Field Evaluation of an Alternative UHPC Mix and Associated UHPC Bridge TR684

Ultra-high performance concrete (UHPC) is a relatively new class of concrete that has material and durability properties superior to normal concrete. These unique properties make it appropriate for use in construction for highway bridges. Field applications of UHPC for highway bridges in the United States started in 2006. For this project, UHPC called K-UHPC, which was developed by the Korea Institute of Civil Engineering and Building Technology, was used for construction of the Hawkeye Bridge in Buchanan County, Iowa. The bridge was built using locally sourced cement, sand, and ready-mix trucks. For the research presented in this report, selected properties of K-UHPC were studied. The research focus was on the evaluation of strength behavior (compressive strength), long-term stability properties (creep and shrinkage), bonding with reinforcement, and durability properties (freeze-thaw resistance and chloride ion penetration). These properties were estimated using samples prepared in two different environments: first, with samples collected from the field environment where K-UHPC was mixed in the Buchanan County Secondary Roads Department yard using conventional concrete mixers; then, using samples prepared in the laboratory. Properties evaluated from these two different scenarios are presented in this report. These are then compared to the properties reported by the Federal Highway Administration (FHWA) for other UHPC mixtures. Finally, the outcome of the load tests performed on the Hawkeye Bridge is presented