The FDR process usually consists of eight steps (Better Roads, 2001):
Pulverization. A road reclaimer pulverizes existing pavement to a predetermined depth. Road reclaimers areusually equipped to add materials such as stabilizing agents to the newly pulverized RAP.
Moisture conditioning. The road reclaimer or a separate truck adds water to the newly pulverized RAP to assist inachieving required density.
Breakdown roller. A sheepsfoot or pneumatic tire roller is typically used to compact the recently pulverized RAP to a consistent density.
Shaping. A grader is typicallyused to make grade and cross-slope adjustments.
Intermediate roller. A pneumatic tire roller or a steel wheel vibratory roller is used to knead and seat any loose aggregates left from the shapingprocess.
Finish roller. A 12 to 14-ton static steel wheel roller is used to seat any remaining loose aggregates and create a smooth surface.
Sealant. A fog seal is typically applied to protect thefinished reclaimed layer. After the fog seal sets the reclaimed layer can generally withstand interim traffic loading. Therefore, at this point the road is often opened to traffic until the contractor isready to apply the surface treatment or HMA surface course.
Surface treatment or surface course. Finally, a more durable surface treatment or surface course is applied over the new stabilized basecourse.
Stabilized base course.
Recycled material, asphalt emulsion or foamed asphalt, asphalt rejuvenating agent and possibly virgin aggregate.
No generallyaccepted mix design method, but the Asphalt Institute recommends and most agencies use a variation of the Marshall mix design method (FHWA, 2001b).
FDR is generally suitable for lowervolume roads that may only require a simple surface treatment over the resulting stabilized base course, or at most a thin HMA wearing course. However, FDR has been used on major highways including...