Full-Depth Reclamation (FDR) is a full pavement rehabilitation process in which the pavement and a portion of the subbase material are uniformly crushed, pulverized and blended. This revitalized gradation can be mixed with an asphalt emulsion or calcium chloride to increase the stability of the rejuvinated material. This process completely rehabilitates and reinforces the structural strength of the underlying base of the road. It 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. This structural upgrade is used when the pavement has been deemed structurally unsound. Examples of such would be roads in constant need of maintenance repairs and those riddled with pot holes.
A mix design must be developed based on core sample analysis. Drainage and shoulder issues must be addressed.
Core samples are taken from the desired construction site. These samples undergo testing and after proper analysis a mix design is developed for the project. With these steps completed, construction can begin. The existing surface is milled 6 to 10 inches deep. Milling down this deep will bring up the surface, base layer, and some soil. The materials are pulverized to a specific aggregate size which is determined within the mix design.
During the second pass of the pulverizing process, asphalt emulsion or chemicals such as calcium chloride or magnesium chloride are added to increase pavement stability. The step that follows the mixing process is the re-application of the product.
Midland Asphalt typically utilizes multiple pass reclamation in which the initial pass is simply to "pre-pulverize" the existing surface. The second pass then unifies the size of the aggregate gradation and a second addition of stabilizers (emulsion or calcium chloride) occurs. Multiple pass reclamation is a superior method to single pass reclamation because it helps to unify material size and may contain double the amount of stabilizing materials.
The next step is compaction. Compaction can be completed by use of one of the following roller types: Double-Drum Steel, Sheep's/Pad Foot or Pneumatic Rubber Tire. Water is continuously applied to keep the surface from drying out until it is able to support traffic. The final step is the application of the chosen surface treatment (i.e. FiberMat®, NovaChip®, chip seal, hot-mix asphalt, etc).
Note: Proper grading and compaction are necessary for optimal results.