Full-Depth Reclamation (FDR) is a mode of full pavement rehabilitation designed to stabilize the base course in a highly deteriorated roadway.
By uniformly crushing, pulverizing, and blending the existing pavement and a portion of its sub-base, FDR addresses reflective cracking problems by getting to the root of the problem– structural deficiencies in the road. Further stabilization can be achieved through the use of additives.
FDR goes one step further than Cold-in-Place-Recycling because it penetrates as deep as the underlying base or sub-base. FDR is commonly used when the road has deteriorated past the point of normal maintenance and shows signs of rutting, cracking, and base weakness or failure.
First, pavement samples are taken from the roadway. These samples are then analyzed to determine the proper mix design for the project. Drainage and shoulder issues must also be addressed. Once these steps are completed, construction can begin. The existing road surface is pulverized to a depth of 5 to 16 inches. Grinding to this depth combines both the surface and base layer(s). Then, there are three different types of stabilization that can be performed.
Midland Asphalt recommends multiple pass reclamation where the initial pass is performed to pulverize the existing surface. During the second pass, additives are blended with the pulverized material. This helps to ensure stabilization and unify the size of the aggregate gradation.
Including additives in the FDR process greatly aids in achieving maximum compaction immediately, instead of over time with traffic.
Compaction can be completed by via the following roller types: Double-Drum Steel, Pad Foot or Pneumatic Rubber Tire. Finally, the application of a wearing course completes this process (i.e. FiberMat®, NovaChip®, Chip Seal, HMA, etc).
Note: Proper grading and compaction are vital for optimal results.