All States Materials Group

Additional Resources

Crumb Rubber Modified
Hot Mix Asphalt

All States Materials Group’s crumb rubber modified (CRM) hot mix asphalt (HMA) is a high performance pavement manufactured and constructed with well-maintained, state-of-the-art equipment by knowledgeable, experienced professionals. The binder is a blend of asphalt and 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 high viscosity elastic binder material that remains flexible at low temperatures and stiff 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, rutting, raveling, delamination, shoving and thermal and reflective cracking. We blend the CRM asphalt binder with high quality aggregates for superior hot mix asphalt performance, and use superior quality construction to build your pavement.

Benefits of Crumb Rubber Modified Hot Mix Asphalt Pavements

  • Resists oxidative aging
  • Resists cracking at low temperatures and rutting at high temperatures
  • Resists raveling and delamination
  • Reduces back spray and improves visibility in wet weather
  • Can reduce HMA lift thickness, preserving curb reveal and clearances under overpasses
  • Improves pavement structure and ride
  • Uses recycled material, reduces scrap tire inventories
  • Durable, high performance mix extends the service life of your hot mix pavements

The CRM HMA Process

All States Materials Group’s crumb rubber modified asphalt is formulated for durability and high performance applications. Our laboratory mix design determines the gradation and asphalt content. To account for the rubber and higher film thickness on the aggregates, the job mix formulas are a little different from conventional HMA mixtures; typically higher voids in mineral aggregate (VMA) and higher binder contents (typically 20% higher) are needed. The HMA is manufactured at our facility with strict quality control for consistency and performance. We use our state-of-the art equipment to manufacture, transport, lay and compact the mix. Our well-trained, experienced crews follow strict procedures for quality construction.

Where and When to Use CRM HMA

While designed for applications where high performance is needed, All States’ crumb rubber modified hot mix asphalt (asphalt rubber) may be used for any HMA paving project, and has proven effective on streets, highways and airfields. Typically, the high performance mix is used for surface courses. It is ideal for high volume highways where durability, lift thickness, visibility, and user delay are concerns. On distressed surface pavements, an All States Materials Group asphalt rubber SAMI under the overlay will retard reflective cracking and prolong the service life of the overlay. The high film thickness makes CRM asphalt especially useful for special mixes such as open-graded friction courses (OGFC), paver placed surface seal, gap-graded mixtures and stone matrix asphalt (SMA). These mixes give outstanding performance in heavy-duty applications. The open mixes greatly improve visibility in wet weather and substantially reduce road noise, but in the past have had some problems with raveling and early aging with conventional asphalt. The crumb rubber asphalt’s thicker film reduces drain down and aging of asphalt, giving the durability to make these high strength stone-on-stone mixes most effective. As with any surface course, CRM HMA should be placed on pavements with sound base structures and good drainage. There should be no sign of sub-base movements or moisture damage.

All State Asphalt’s professionals work with municipal, state and consulting engineers on a job-by-job basis to construct need-specific asphalt rubber hot mixes. We can help with such issues as equipment rentals and aggregate supply as well as our superior quality complete turnkey contracting. We will be there to make sure you are satisfied. Contact us for more information on how to use our crumb rubber modified asphalt to its best advantage on your projects and extend pavement life.