Bridge decks constructed using low-cracking high-performance concrete (LC-HPC) have performed exceedingly well when compared with bridge decks constructed using conventional procedures. The original LC-HPC decks were constructed using 100% portland cement concretes with low cement paste contents, lower concrete slumps, controlled concrete temperature, minimum finishing, and the early initiation of extended curing. Methods to further minimize cracking, however, such as internal curing in conjunction with selected supplementary cementitious materials, shrinkage-reducing admixtures, shrinkage-compensating admixtures, and fibers have recently been applied in conjunction with the LC-HPC approach to bridge-deck construction with good results. Laboratory research and field applications have demonstrated that the use of three new technologies, (1) internal curing provided through the use of pre-wetted, fine lightweight aggregate in combination with slag cement and fly ash, with or without small quantities of silica fume, (2) shrinkage compensating admixtures, and (3) steel and synthetic fibers can reduce cracking below values obtained using current LC-HPC specifications. The goal of this project to apply these technologies to new bridge deck construction and establish their effectiveness in practice. State departments of transportation expend significant effort and resources on the construction of durable reinforced concrete bridges and bridge decks. Existing data show that the modifications to construction procedures, materials, and design details used in LC-HPC bridge deck construction, without and with the newer technologies, significantly reduce the degree of cracking and, thus, reduce exposure of reinforcing steel to the corrosive effects of deicing chemicals, decrease freeze-thaw damage, and improve deck performance under all environmental conditions. The project will combine knowledge from research and practice to develop a comprehensive strategy for the construction of low-cracking bridge decks. If successful, the result will lead to an improvement in durability and an increase in the useful life of bridges

1. Work with state DOTs on specifications for LC-HPC bridge decks to be constructed over the three-year period of performance of this project. 2. Provide laboratory support prior to construction and on-site guidance during construction of the LC-HPC bridge decks. 3. Perform detailed crack surveys on the bridge decks. If desired, DOT personnel will be trained in the survey techniques and may assist in the surveys, as appropriate. 4. Correlate the cracking measured under objective 3 with environmental and site conditions, construction techniques, design specifications, and material properties, and compare with results obtained on earlier conventional and LC-HPC bridge decks. 5. Document the results of the study. Provide recommendations for changes in specifications.

This study will provide laboratory and on-site construction support for individual bridge decks with the expectation that each state will construct two bridge decks per year using the new technology. The crack surveys will be performed 1 year and 2-3 years following construction during the three-year period of performance of this project, and (if approved under subsequent projects) up to 5 years after construction. Detailed reports will be completed for each deck, and the results will be used to develop bridge deck materials and construction specifications that best fit with the practices of the participating states.

The budget is based on $135,000 ($45,000 per year) per state with minimum of two states (funding provided by Kansas and Minnesota). Additional states may participate at the same rates.