You have a new road repair project. You may have heard the terms asphalt milling and full depth reclamation and wondered what the difference is between them. While they are both road repair methods for asphalt pavement, they repair the existing pavement in different ways. Pavement milling and full depth reclamation also have different long-term outcomes.
What is Asphalt Milling?
There are many benefits of asphalt milling. The milling process involves removing the existing asphalt layer to prepare it for asphalt resurfacing.
Cold milling or profiling are other words for asphalt milling. Road crews use a specialized milling machine with rotating cutting drums to grind away the existing pavement. Some key characteristics of asphalt milling include the following:
- Asphalt removal: asphalt milling removes only the top asphalt layer of the pavement, usually 1 to 4 inches deep. Asphalt milling machines remove only the alligator cracked pavement, leaving the undamaged asphalt layer intact.
- Resurfacing preparation: After road crews remove the damaged asphalt, they apply a new layer of asphalt to the existing material.
- Asphalt recycling potential: road crews haul away the asphalt millings. They use the recycled asphalt for future construction projects.
Crews use asphalt milling to fix surface defects in the existing asphalt pavement. A milling machine also improves road smoothness, corrects drainage issues, and prepares the existing asphalt for overlay.
What is Full Depth Reclamation (FDR)?
Full depth reclamation, also called full depth recycling or FDR, is a much more comprehensive process than asphalt milling. Road crews pulverize the entire existing pavement with the road base and sub base and mix it together. The process of full depth reclamation creates a stable, strong, and long lasting road foundation.
Road crews use full depth reclamation to strengthen the road base and get rid of pot holes, ruts, or cracks. Here are the key features of the FDR process:
Complete asphalt removal: an asphalt milling machine pulverizes and mixes together the existing asphalt pavement with the road base material.
Add Stabilizers and Compact: Road crews add water to the pulverized asphalt and road base. Sometimes they also add additional materials such as cement, lime or asphalt emulsion to enhance strength and stability.
Reconstruction: Finally, road crews compact the materials, creating a new solid road base. They pave over the new surface or chip seal it.
Cost-effective and sustainable: Full depth reclamation reuses existing asphalt as road base. This limits the amount of new aggregate production. It also keeps pothole ridden asphalt out of the land fill, and eliminates transportation costs. This makes full depth reclamation a cost effective solution that is good for the environment.
Should I Use Asphalt Milling or Full Depth Reclamation for My Road Repairs?
If you are trying to decide between asphalt milling or full depth recycling, there are a few factors to consider:
- Your Asphalt Road Condition: If your asphalt has surface defects, minor cracks, or unevenness, pavement milling might be a good solution. It selectively removes the top layer of asphalt while preserving the underlying layers. FDR is better if you have an unstable road base or alligator cracks and potholes.
- Your Road Repair Budget: Asphalt milling can be less expensive short term because it fixes only the asphalt surface. Full depth reclamation is a more in depth process that may involve an upfront investment. The right equipment can lessen the impact to your budget.
- Asphalt Pavement Outcome: Asphalt milling will address defective asphalt surfaces, improve road smoothness, or prepare for a new asphalt layer. Full depth reclamation is a long term road repair solution. It addresses the underlying structural issues and provides a stable road foundation.
- Environmentally Friendly: both asphalt milling and full depth reclamation recycle asphalt. With the milling process, you will need to haul away the used material for other projects. Full depth reclamation recycles the asphalt millings as road base, avoiding the cost of transportation and purchasing new materials.
Summing it Up: Comparing Full Depth Reclamation and Asphalt Milling
Asphalt Milling removes the top surface of the pavement, providing a temporary fix to pot holes and cracks. Full depth reclamation pulverizes the entire asphalt surface with a predetermined portion of the road base. FDR reconstructs the entire pavement structure and provides a long-term and cost effective repair solution.
With asphalt milling, you remove the asphalt millings to dispose of them or re use them. FDR reuses the millings to strengthen the road base, ending the need to dispose of the asphalt millings. Deciding which method to use will depend on the condition of your asphalt and road base and your budget. Perhaps most important, you will need to decide how long you want your road repair to last.