Evaluation of Asphalt Mixture with High Percentage of Reclaimed Asphalt Pavement in Florida

Abstract

This study examined the long-term performance and life span of mixture designs with a high percentage of reclaimed asphalt pavement (RAP) (≥30%) used on higher-tonnage (>5,000 tons) projects. The pavement performance of mixtures containing high RAP percentages and mixtures containing no RAP was compared for the period 1991 to 1999. The pavements analyzed contained a lower structural layer that contained RAP and an upper layer that contained either an open-graded or dense-graded non-RAP friction course. Several databases were consulted to obtain the necessary information regarding tonnage, mixture designs, percentage of RAP, project information, traffic volumes, pavement performance, and life span. A trend showing that the time needed for the pavement to reach a deficient state decreased as the percentage of RAP increased was evident when the data were examined without accounting for the volume of traffic. When traffic volume was accounted for and projects ≥5,000 tons were isolated, a trend of decreasing performance with increasing amounts of RAP was seen. However, in the range analyzed (30% to 50% RAP), all mixtures containing RAP performed better than the mixtures containing no RAP. Consideration of the type of non-RAP friction course placed over the RAP mixtures showed that as the amount of RAP increased, pavement performance decreased at the same rate, regardless of the type of friction course. Although this trend may be correct, the implication that RAP mixtures overlaid with an open-graded friction course have a longer life span than RAP mixtures overlaid with a dense-graded friction course may be the result of factors that are not correctly reflected in this data set.