Virginia's Higher Specification for Reclaimed Asphalt Pavement

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Virginia's Higher Specification for Reclaimed Asphalt Pavement

Performance and Economic Evaluation

Maupin, G. W. / Diefenderfer, Stacey D. / Gillespie, James S.

In 2007 the Virginia Department of Transportation (VDOT) decided to allow higher percentages–-more than 20%–-of recycled asphalt pavement (RAP) in hot-mix asphalt with no change in binder grade. For selected VDOT resurfacing projects in 2007, six contractors produced a total of 129,277 tons of mix containing 21% to 30% RAP from seven asphalt plants in four districts. This study estimated the effect of increased RAP percentages on performance and relative cost. Mixes from most of the high-RAP jobs were sampled and tested, as were mixes from roughly comparable jobs containing less than 20% RAP. Laboratory tests revealed no significant difference between the higher RAP mixes and the control mixes for fatigue, rutting, and susceptibility to moisture. Recovered binder was graded to determine the effect of adding higher percentages of RAP. No construction problems were attributed to the use of the mix with the higher RAP percentage. Slight price adjustments were applied to two of the 10 high-RAP projects, but these were not because of the higher RAP percentage. Price and quantity data from all contracts in the 2007 resurfacing schedule were subjected to statistical analysis. The specification allowing higher RAP percentages was found to have a small, statistically insignificant impact on the bid prices for surface mix items. Value engineering proposals received for jobs not advertised with the high-RAP specification showed that the use of more than 20% RAP could reduce costs in at least some cases.