A TEN YEAR PERFORMANCE SUMMARY OF PC CONCRETE & CONCRETE OVERLAY RESEARCH IN GREEN COUNTY, IOWA

Abstract

This study provides a comprehensive performance summary of a concrete overlay project conducted in Greene County, Iowa, over a decade, analyzing various types of concrete overlays in terms of durability and effectiveness. Initiated in October 1973, the project evaluated 33 fibrous concrete sections, along with continuously reinforced concrete pavement (CRCP), mesh-reinforced, and plain concrete sections with doweled reinforcement. After ten years, these sections were assessed for deterioration, and their performance was rated by a panel from the original Project Planning Committee, Iowa Department of Transportation, Federal Highway Administration, and others. The evaluation revealed that non-fibrous mesh reinforced and bar reinforced concrete overlays exhibited superior durability and performance compared to fibrous reinforced sections. The study specifically noted that sections with 160 pounds of fiber per cubic yard showed the best performance among fibrous overlays, while increasing cement content from 600 to 750 pounds per cubic yard did not yield significant benefits. Furthermore, it was observed that the 3-inch thick fibrous concrete overlays performed better than 2-inch ones. Despite various efforts, substantial bonding was not achieved in fibrous concrete sections, leading to indeterminate conclusions about the effectiveness of different bonding techniques. Overall, the additional costs of fibrous concrete could not be justified by their performance, making thicker, non-fibrous overlays a more viable option based on this ten-year evaluation. Future studies are planned to continue monitoring these sections to further understand long-term durability and performance. (Abstract generated by AI tool ChatGPT 4)