Minnesota Department of Transportation
Bonded concrete overlay of asphalt (BCOA) pavements, also known as whitetopping, can help enhance the structural capacity and rideability of existing asphalt pavement. In this report, the generic term "BCOA" is used to describe all overlays that are between 3-inches and 7-inches thick and placed on an asphalt layer a minimum of 3-inches thick. BCOA is typically designed for a 20-year design life. Rehab should be considered when the distresses in a BCOA are causing ride quality issues or the panels have deteriorating cracks. Agencies have generally utilized concrete pavement restoration (CPR) techniques used for standard concrete pavements on grade to repair such overlays. However, these techniques may or may not be the appropriate repairs to address similar distresses in BCOA pavements. Over the past decade, the popularity of BCOA pavements has grown in many states and many of these projects are now reaching an age where rehab is needed. This has prompted the National Road Research Alliance (NRRA) to compile a synthesis of current practices of repairs being used on BCOA projects by the contributing state agencies. The most common type of repair of a BCOA pavement is to conduct a full-depth removal and replacement of the concrete panels when the area of distresses is localized. The main supporting factor is the BCOA pavement has such a thin overlay that it is more cost effective to perform this type of rehabilitation method as compared to the others.
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