Incorporation of Reclaimed Asphalt Pavement (RAP) in P-401 Mixtures
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Authors
Devkota, Prakrit
Issue Date
2025
Type
Thesis
Language
en_US
Keywords
Airfield , Asphalt , Mixtures , Pavement , Performance , RAP
Alternative Title
Abstract
The use of Reclaimed Asphalt Pavement (RAP) has been widespread in highway pavements for decades, with both laboratory studies and field data demonstrating that RAP in moderate contents, about 20%, can yield mixtures that perform equally or better than virgin asphalt mixtures. As such, the use of RAP has been broadly adopted by various state Department of Transportation (DOTs) across the country. In addition, the use of RAP offers economic and environmental benefits, including lower costs and reduced demand for virgin materials, as well as enhanced sustainability. However, the Federal Aviation Authority (FAA) prohibits the use of RAP in surface course mixtures, as per its P-401 specifications, due to concerns about durability, foreign object debris (FOD) generation, and workability issues. This study examines the feasibility of incorporating 20% RAP into FAA P-401 surface mixtures, utilizing various performance tests to ensure compliance with performance requirements, including durability and workability. The research addresses one of the main challenges with the use of RAP: the recycled binder availability (RBA), which is critical to understanding the effective contribution of aged RAP binder in asphalt mixtures. The traditional methods for volumetric mix design overestimate this contribution, which leads to stiffened mixtures. For mix design, a 1% air void regression approach was applied to mixtures with RAP to offset the deficiency in available binder and improve performance. Laboratory tests indicated that mixes designed in this manner consistently met or exceeded the P-401 specification performance criteria.
The laboratory testing indicated that the inclusion of RAP in airfield surface mixtures, combined with a 1% air void regression that led to the addition of asphalt binder, maintained acceptable rutting resistance while also enhancing the cracking performance. Further, the mixtures performed well in terms of moisture susceptibility and durability. The workability of the mixtures was found to remain within acceptable limits and was highly dependent on the mixture. Overall, the 1% regression in air voids effectively balanced the performance without compromising any key properties, although the results were mixture dependent. These findings support the controlled use of RAP in surface mixtures for airfield pavements; however, this study highlights the need for further evaluation through additional testing and long-term performance predictions.