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 LC-HPC decks have been constructed using 100% portland cement concretes with the low cement paste contents, lower concrete slumps, controlled temperature, minimum finishing, and the early initiation of extended curing. Methods to further minimize cracking, such as internal curing in conjunction with selected supplementary cementitious materials, shrinkage-reducing admixtures, shrinkage-compensating admixtures, and fibers have yet to be applied in conjunction with the LC-HPC approach to bridge-deck construction. Laboratory research and limited applications have demonstrated that the use of two new technologies, (1) internal curing provided through the use of pre-wetted, fine lightweight aggregate in combination with slag cement, with or without small quantities of silica fume, and (2) shrinkage compensating admixtures, can reduce cracking below values obtained using current LC-HPC specifications.

The purpose of this study is to implement new technologies in conjunction with low-cracking high-performance concrete bridge specifications to improve bridge deck life through reduction of cracking. The work involves cooperation between state departments of transportation (DOTs), material suppliers, contractors, and designers. See scope of work.

1. Work with state DOTs on specifications for the construction of six LC-HPC bridge decks per state to be constructed over a three-year period. 2. Provide on-site guidance during construction of the LC-HPC bridge decks. 3. Perform detailed crack surveys on the bridge decks, 1 year, 2-3 years, and (if approved) 4-5 years after construction. Prior research has demonstrated that it takes at least three years to consistently establish the long-term cracking performance of a bridge deck. The surveys will be performed using techniques developed at the University of Kansas to identify and measure all cracks visible on the upper surface of the bridge deck. If desired, DOT personal will be trained in the survey techniques and may assist in the surveys, as appropriate. 4. Correlate the cracking measured in Task 3 with environmental and site conditions, construction techniques, design specifications, and materials properties, and compare with results obtained on earlier conventional and LC-HPC bridge decks. 5. Document the results of the study. Interim and final reports will be prepared covering the findings in Tasks 1-4.

100% SPR Funding has been requested.