Design and Quality Control of Concrete Overlays

The United States has a significant investment in civil infrastructure, which is deteriorating under heavy use, age, and environmental attack. A large proportion of this infrastructure consists of plain and reinforced concrete pavements and bridge decks. Concrete overlays have been used for pavement and bridge deck rehabilitation for many years. Concrete overlays on pavements or bridge decks can fulfill three design functions - they can strengthen the structure against further deterioration due to fatigue cracking (or rutting, with whitetopping overlays), they can improve smoothness and restore ride quality, and they can add skid resistance. This research developed and tested a range of plain and fiber reinforced concrete overlay mixes that allow reliable, economic, and durable overlay construction as well as early opening to traffic. This report documents the benefits of using nondestructive testing technologies, including spectral analysis of surface waves, in overlay investigation, planning, construction, and quality control. Analytical modeling using the HIPERBOND module of the program HIPERPAVE was used to investigate behavior and performance prediction for the eight overlay concrete designs investigated in the laboratory testing program. So far, two ultrathin whitetopping overlays have been constructed in Alabama, on heavily traveled asphalt pavements in Selma and Jasper. Both projects were constructed in the outside lanes at intersections, where stopped trucks caused considerable rutting over the years. Performance of the two overlays to date has been very good. Recommendations are made in this report for materials selection, design, and construction controls for overlay construction.