A System for Capturing the Value of Worn-Out Pavements
When an asphalt pavement is reaching the end of its life cycle or is showing early distress, it can be overlaid with a new surface, or it can be recycled using a number of different techniques. Which technique to choose depends on a number of factors, including geographical location, available equipment, road depth, road condition, climate, traffic flow, curb height, quality of existing materials, and the underlying structure.
Why Recycle?
There are several obvious advantages to recycling, and some that are not so obvious:
- An aged, distressed pavement is replaced with a new, smooth, durable surface.
- Recycling reuses the existing aggregate and asphalt, cutting down on new raw material costs. When done in-place, hauling costs are reduced.
- Cracked pavement is removed, delaying future reflective cracking.
- Deformations such as potholes, ruts, and shoved pavement are leveled.
- Drainage problems can be fixed.
- Crowns can be re-established.
- Clearances under bridges and curb height can be restored.
- With the proper choice of materials, aged asphalt can be rejuvenated, and poor aggregate gradations can be corrected.
- Polymers can be added to improve flexibility, adhesion, strength and resistance to temperature extremes.
- In some locations, the large piles of material milled off of old pavements are becoming a problem. This RAP (reclaimed asphalt pavement) can be used as a valuable raw material instead of being considered as waste.
- In-Place recycling minimizes the time a lane is closed for re-construction.
- The savings in costs of new materials can be applied to increasing the improvements in our streets and highways.
- There is excellent public acceptance of recycled materials.
- The recycled pavement can, itself, be recycled when its time has come.
When to Recycle?
Almost any distressed asphalt pavement can be recycled, but the following are cases where recycling can solve existing problems most cost-effectively over the long term.
- A pavement has reached the end of its design life and exhibits classic alligatored fatigue cracking.
- There are drainage problems.
- There are problems with the underlying pavement structure.
- A newly laid pavement is rutting and shoving.
- A pavement is marred with thermal cracks that have raveled to form potholes.
- There are low clearances under bridges and overpasses.
- Curbs and gutters are no longer protecting lanes, sidewalks and adjacent properties from storm water.
Where to Recycle?
There have been successful recycling projects on rural roads, city streets and Interstate highways. As in any paving project, the design (including material selection and construction method) should be based on the particular situation.
How to Recycle?
Several very effective techniques have led recycling to become an accepted part of the asphalt paving industry. The key to a successful project is an analysis of the existing conditions and selection of the best available materials and method.
We Can Help
We've been providing asphalt paving products and expertise for recycling for many years. Let us help you in selecting the system available in your area which best suits your needs. Your local SemMaterials representative will be happy to supply further information about the Recycle Plus® and Reflex® systems, and help in selecting the right process for your paving needs.
Asphalt Recycling Glossary
- Asphalt content. The percent by weight of asphalt cement of the total asphalt/aggregate mixture.
- Cold In-Place Recycling (CIR) . Removing, crushing, blending with emulsified asphalt, re-laying and compacting an existing pavement in the same location.
- Cold Planing. Removal of pavement to a desired depth using specially designed equipment.
- Emulsified Asphalt. An emulsion of asphalt cement particles suspended in water, stabilized by a surface active emulsifying agent.
- Encore® Emulsion Hot In-Place Recycling. SemMaterials' improved emulsion for hot in-place recycling (HIR).
- Extracted Aggregate. Aggregate separated from a sample of aged asphalt pavement.
- Extracted Asphalt. Asphalt extracted from a sample of aged asphalt pavement.
- Hot In-Place recycling (HIR). Heating, scarifying, blending with emulsified or hot asphalt, re-laying and compacting an existing pavement in the same location. Additional virgin hot mix can also be blended with the recycled mix.
- Reclaimed Aggregate Material (RAM). Removed pavement material containing no reusable binder.
- Reclaimed Asphalt Pavement (RAP). Removed pavement containing asphalt and aggregate.
- Recycling. Re-using a material that has already served its first-intended purpose. Normally this requires some re-processing.
- Rejuvenating Agent. A material which helps restore the desired physical properties to an aged, oxidized asphalt binder.
- Recycle Plus® Recycled Asphalt Pavement. SemMaterials' improved system for recycling asphalt pavements and RAP which have reached the end of their life cycle.
- Reflex® emulsion cold in-place recycling. SemMaterials' improved cold-in place recycling system.