Asphalt rubber SAMs (Stress Absorbing Membranes) serve as highly durable wearing surfaces for demanding pavements. The innovative surface treatment includes 3/8” or 1/2" stone placed over a thick (0.5 to 0.7 gallons per yd2) hot-applied binder composed of asphalt blended with 20% by weight rubber from recycled tires. The tire rubber is finely ground at ambient temperatures then blended with asphalt at temperatures exceeding 350ºF. The high temperature causes the oils in the asphalt to swell the elastomeric rubber polymer, resulting in a stiff, elastic and flexible binder material that is less sensitive to brittleness at low temperatures and bleeding at high temperatures. The tire rubber contributes polymer, carbon black and anti-oxidants. The result is a very adhesive and cohesive high viscosity binder that gives high film thickness on the aggregates, improving durability and resistance to oxidative aging, aggregate loss and delamination. The SAM durability doubles the life of conventional chip seals and reduces spalling around existing reflective cracks.
Benefits of Asphalt Rubber SAMs
- Waterproofs and seals small cracks and imperfections on the existing pavement surface
- Minimizes loss of curb reveal and alignment; thinner than hot mix overlays
- Uses recycled material, reduces scrap tire inventories
- More durable than conventional asphalt
- Developed for high traffic volume roads
- Quick construction and traffic return with minimal user delays
- Long lasting preventive maintenance preserves the value of your structurally sound pavements with distressed surfaces
The SAM Process
All States Materials Group’s asphalt rubber is formulated for durability and adhesiveness. It is manufactured at our facility with strict quality control for consistency and performance. We use coated and heat-treated high quality stone that has been tested for shape, hardness, proper gradation and cleanliness. A laboratory design with the project materials determines the correct asphalt rubber and aggregate application rates. There should be sufficient asphalt to give the proper embedment (and therefore bonding) of the aggregate in the asphalt, and just enough aggregate to cover the surface (typically 30-35 pound per yd2). After any repairs are made and the pavement is cleaned of any loose debris, a properly adjusted and calibrated distributor truck sprays the hot asphalt rubber on the pavement at the predetermined shot rate. This is immediately covered by the aggregate from a continuous, self-propelled aggregate spreader. The seal is then rolled to properly orient and seat the aggregate. After any excess aggregate is swept off, the newly surfaced road can be opened immediately to traffic.
Where and When to Use Asphalt Rubber SAMs
Asphalt rubber SAMs are designed for demanding, high traffic volume highways; but they may be used on any type of road where a high performance surface treatment is wanted. They are ideal for cracked and raveled surfaces where traffic delays, curb reveal, and clearances under bridges and overpasses are a concern. The pavement to be sealed should be structurally sound and properly drained. It should have a good profile, but may have aged asphalt with extensive surface cracking and raveling. There should be no sign of sub-base movements or surface bleeding. When warranted, potholes and cracks should be filled. The surface should be swept of any stones, sand, mud or other loose debris. Asphalt Rubber SAMs are the long-lasting treatment for distressed-surface pavements that you want to preserve. All States Materials Group wants to make sure your surface treatment job is a success. We can help with determining the right treatment at the right time for your pavement. For your overall road program, we can help you evaluate single versus multiple surface treatments, equipment rentals and aggregate supply instead of our complete turnkey contracting. Contact our professionals for more information about how asphalt rubber SAMs can help you preserve your pavements.