Full Depth Reclamation

Full-Depth Reclamation (FDR) is a full pavement rehabilitation process in which the pavement and a portion of the sub base material are uniformly crushed, pulverized and blended. This results in a stabilized base course. Further stabilization may be obtained through the use of additives. FDR addresses reflective cracking problems by completely recycling base and sub base structural deficiencies.

FDR is different from Cold-in-Place Recycling due to the fact that it always penetrates as deep as the underlying base or sub-base. FDR is commonly applied when there are signs of rutting, cracking, base weakness or failure and when the profile of the road has deteriorated past the point of normal maintenance.

Process

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. With these steps completed, construction can begin.  The existing surface is pulverized 5 to 16 inches deep. Grinding to this depth will combine the surface and base layer(s). When pulverization is performed without chemical or bituminous additives, this is commonly referred to as Mechanical Stabilization.

  • Mechanical Stabilization (Pulverization) – The existing pavement layers are blended with a predetermined portion of the sub base material using a Reclaimer/ Stabilizer. Mix design may dictate that the addition of aggregate is required.
  • Bituminous Stabilization – Bituminous liquids are blended into the pulverized material through the machines integrated liquid additive injection system either during the pulverization pass (single pass) or in a subsequent mixing pass (multiple pass).
  • Chemical Stabilization – Chemical additives such as Chlorides and Portland cement are applied as mentioned above or applied on the road surface, directly in front of the pulverizer.

Midland Asphalt recommends multiple pass reclamation in which the initial pass is performed to pulverize the existing surface. During the second pass, additives are blended with the pulverized material. This also helps to unify the size of the aggregate gradation. Including additives in the FDR process, greatly aids in achieving maximum compaction today, instead of over time with traffic.

Compaction can now be completed by use of one of the following roller types: Double-Drum Steel, Pad Foot or Pneumatic Rubber Tire. 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.

Value Added Benefits

  • Economical
  • Complete structural repair
  • Correct base layer distress
  • Shoulder strengthening
  • Road widening
  • Drainage improvement
  • Recycles existing materials
  • Eliminates material disposal concerns
  • Grade and cross slope can be re-established

Compatible Processes