Laboratory Evaluation of Workability and Moisture Susceptibility of Warm-Mix Asphalt Mixtures Containing Recycled Asphalt Pavements

Warm mix asphalt (WMA) and recycled asphalt pavements (RAP) are two popularly used sustainable technologies in pavement industry. Because RAP materials contain aged binder, its use is limited to a certain percentage in hot mix asphalt (HMA) as it may affect the workability and, fatigue and thermal cracking performance. Higher percentages of RAP can be incorporated into HMA with softer asphalt binder or in combination with softening agent. However, the combination of WMA and RAP may allow for greater percentages of RAP without modifying the original HMA job mix formula. The objective of this study was to explore the use of higher percentage of RAP, using two different WMA technologiesEvotherm additive and foamed asphaltto study the workability and moisture sensitivity of WMA-RAP asphalt mixtures. The study found that the use of WMA technologies can eliminate the need for a softer grade binder in high RAP mixtures. (C) 2016 American Society of Civil Engineers.