Verification of the whitetopping thickness design procedure for asphalt concrete overlaid Portland cement concrete pavements

Iowa is one of few states with a large number of Portland Cement Concrete (PCC) pavements. Many of these pavements have been rehabilitated by placing multiple layers of Asphalt Concrete (AC) over the existing PCC slabs. However, there was a need for an alternative with a longer life and lower life-cycle cost. With improvements in paving technology such as the slipform paver and the ability to obtain high early age strength, PCC overlays soon became that alternative. Many of the existing overlay design procedures were developed for a single placed layer of pavement and are not applicable to the two layered AC/PCC pavements. Previous research developed a method so that the single placed layer concept can be applied to the analysis and design of overlays for AC/PCC pavements. The study presented here is an extension of this research. It investigates existing design methodologies and presents modifications for future research