Crumb Rubber and Polymer
Modified Asphalt (CRMA)
While asphalt is a viscoelastic, highly viscous liquid that has excellent flexibility, waterproofing and adhesive properties, it has a tendency for brittleness at very low temperatures (which leads to cracking and shelling) and flow at very high temperatures (which leads to rutting and bleeding) and oxidative and fatigue aging (which results in loss of flexibility). To improve asphalt physical properties and extend the serviceable temperature range, All States Materials Group supplies modified asphalts for hot mix, emulsions and special applications. The modifiers are designed to be compatible with the chemistry of the asphalt and to give the desired enhanced properties. Where reflective cracking is a concern, the reinforcement of viscoelastic polymers can greatly improve the ability of the asphalt binders to remain intact over cracks which expand and contract with temperature and traffic. Where temperature extremes are a concern, the serviceable temperature range is greatly extended by modifiers. In heavy traffic, the rut and fatigue resistance can be greatly improved with the elasticity, durability and higher stiffnesses imparted by viscoelastic polymers. With the judicious selection of materials, modified asphalts can cost-effectively extend the service lives of pavement layers and surfaces, leading to better quality roads, lower user delays for maintenance and reconstruction, and overall lower life cycle costs. All States is proud to be on the forefront of manufacturing and using modified asphalts for innovative techniques. Our modified products include:
- PG Graded Asphalts
- Crumb Rubber Modified Asphalts
We want to help you provide longer lasting, lower life cycle cost pavements. Contact us for more information on which products will work the best for your applications and meet your expectations for performance.
PG Graded Asphalts
The test methods and specifications developed by the $150 million Strategic Highway Research Program (SHRP) led to the PG binder grading system. Our researchers use these tests to formulate asphalts to meet the specifications and to give the expected performance as well as quality control on our materials. To meet the more demanding PG grades, we supply polymer modified materials to give outstanding performance during mixing, construction and long-term on the road. We understand how important a consistent supply of quality asphalt is to the paving construction industry. To this end, we market and deliver quality paving grade PG asphalts through our terminal. Our terminal and insulated transports include state-of-the-art, well-maintained tanks and equipment, and we run strict quality control evaluations on all our products. We know how important it is that asphalts meet specifications and that they are delivered on time.
Benefits of All States Materials Group’s Modified PG Graded Asphalts
- Our strict quality control gives consistent, quality materials
- Meets all AASHTO, state and local specifications
- Delivered on spec, on time, on temperature
- Premium asphalts for lower life cycle costs on the most demanding applications
Modified PG Graded Asphalt Uses
The primary use of PG asphalt is in the manufacture and construction of hot mix asphalt pavements. The higher, modified grades are designed for use on pavements with temperature extremes, high traffic volumes, braking and stopping traffic and over crack relief interlayers. They are used for Superpave mixes as well as specialty mixes such as open-graded friction courses and stone matrix asphalt to provide higher film thicknesses, less drain-down and more elastic durability. The materials we supply are ready-to-use in conventional hot mix plants and construction equipment. In some cases, tanks of the materials should be agitated or rolled over to make sure there are no temperature differentials or segregation within the asphalt. Mix, laydown and compaction temperatures for modified materials do not always follow conventional guidelines. Contact us for information on the best handling and usage of the material you are using. We can also supply you with more information about how our asphalt can help you provide a cost-effective, high quality and well-maintained road network for the driving public, or how we can provide you with an asphalt for your special application.
Crumb Rubber Modified Asphalt
All States Materials Group’s crumb rubber modified asphalt (CRM) is a high performance binder for hot mix asphalt (HMA). It is 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 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.
Benefits of Crumb Rubber Modified Asphalt
- Gives a high film thickness
- Resists oxidative aging
- Resists cracking at low temperatures and rutting at high temperatures
- Prevents raveling of open- and gap-graded mixes
- Can reduce HMA lift thickness, preserving curb reveal and clearances under overpasses
- Uses recycled material, reduces scrap tire inventories
- Durable, high performance binder extends the serviceable life of your hot mix pavements
Uses of Crumb Rubber Modified Asphalt
All States Materials Group’s crumb rubber modified asphalt is formulated for durability and high performance applications. It is manufactured at our facility with strict quality control for consistency and performance, as well as meeting all of your specifications. It is delivered ready-to-use for manufacture of HMA in traditional hot mix plants and placement with conventional HMA paving equipment. While designed for applications where high performance is needed, it may be used for any HMA paving project, and has proven effective on streets, highways and airfields. It is an ideal product for stress absorbing membrane interlayers (SAMI). The high film thickness makes it 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 have had some problems with raveling with conventional asphalt. The crumb rubber asphalt’s thicker film reduces drain down and aging of asphalt, giving the durability to make these mixes most effective. To account for the rubber, the designs are a little different; typically higher voids in mineral aggregate (VMA) and higher binder contents (typically 20% higher) are needed. Contact us for more information on how to use our crumb rubber modified asphalt to its best advantage.