Engineering properties of bituminous mixtures blended with second reclaimed asphalt pavements (r²ap)

Reclaimed asphalt pavements (RAP) have been called one of the most recycled materials in the world. Pavements mixed with RAP would be milled or excavated when they reach the end of service life. The reuse of RAP makes it as a second RAP, and is referred as R²AP in this study. R²AP was added at ten levels to hot-mix asphalt mixtures (HMA) with four different recycling agents in the laboratory. Adding 40% R²AP did not appear to alter the mixture properties dramatically. When the percentage was higher than 40%, the aged binder in R²AP created a significant change in the mixture properties. All the mixtures showed an increase in energy loss with an increase in R²AP percentages. The higher energy loss in the R²AP mixture indicated a higher possibility of moisture-induced damage. There should be a limit on percent R²AP that could be incorporated into HMA.