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Environmental and Health Issues and Recommendations  Recycled Content:
California is faced with the significant challenge of diverting or safely managing more than 40.2 million reusable and waste tires generated each year. California has an estimated 1.5 million waste tires that have been illegally dumped or stockpiled. These stockpiles pose a potential threat to public health, safety, and the environment.
See the Introduction for complete descriptions of these environmental and health issues.
BACKGROUND AND ENVIRONMENTAL AND HEALTH ISSUES
California has more registered vehicles than any other state. As a result, approximately 40 million reusable and waste tires are generated each year. An additional 1.5 million waste tires remain in unpermitted stockpiles throughout the state, posing a health and safety risk for the public.
California is faced with the challenge of diverting or safely managing these waste tires The California Integrated Waste Management Board (CIWMB) is dedicated to finding new uses for this valuable resource, and to working in cooperation with local governments, industries, and the public towards reaching this goal. CIWMB staff estimates that of the approximately 40 million reusable and waste tires generated in 2004, approximately 30 million of the tires (75 percent) were diverted through various alternatives, including reuse, retreading, and combustion.
Currently, the recycling markets in California do not consume all of the waste tires generated. Waste tires need to be stored safely until sufficient markets are in place to increase the consumption of waste tires. The CIWMB provides a waste tire management framework by enforcing waste tire facility and waste tire hauler regulations. As the use of tires as feedstock material in commercial applications increases, illegal stockpiling and the need for permitted storage will decrease or cease to exist.
The California Department of Transportation (Caltrans) is committed to helping reduce the number of waste tires entering California's landfills. Since 2002, Caltrans has utilized more than 9 million waste tires in highway construction projects, averaging nearly 2 million waste tires per year. Of this amount, approximately 8 million waste tires were used in rubberized asphalt concrete (RAC) projects.
Environmental and Health Issues
Recycled Content
Caltrans has established a variety of uses for waste tire products. They include RAC as a pavement alternative and tire-derived aggregate (TDA), which consists of shredding waste tires and using them as lightweight fill material for embankments. In addition, Caltrans uses recycled offset blocks in metal beam guardrail installations and recycled rubber mats for weed control underneath guardrails. When appropriate and cost-effective, RAC and TDA are the department's first choice.
Caltrans has been using rubber (called crumb rubber modifier (CRM)) in asphalt pavements since the 1970s, in chip seals, and the 1980s, in rubberized asphalt concrete. Early trials included the use of both the wet and dry processes of incorporating CRM; however, most of the work completed in the 1990s and in this decade has employed the wet process. The performance of the projects has varied from poor to excellent, but in recent years improved specifications and practices have provided more consistent performance. Other agencies, primarily the Arizona, Florida and Texas Departments of Transportation, have also used scrap tire rubber in asphalt pavements over this same period, generally with good success.
In 2003, Caltrans established a goal of using at least 15 percent RAC compared to all flexible pavement by weight. The department has exceeded this goal each year. Currently, RAC usage is at an all-time high in Caltrans.
Beyond the obvious environmental benefit of reducing landfill waste by recycling scrap tires for use in pavements, there could also be pavement performance enhancements such as improved durability and reduced noise. In January 2004, Caltrans and the CIWMB entered into an interagency agreement to supplement Caltrans effort in arriving at technically sound, cost effective, and environmentally friendly solutions to scrap tire management through the increased use of scrap tire rubber in roadway projects.
While Caltrans has met its goal in the amount of RAC tonnage, local governments are using the product more and more. In addition to two CIWMB RAC grant programs that may total $4 million or more, the California Legislature added an additional $5 million to the Board's budget this year (and, it is expected, next year) for RAC and tire-derived aggregate grant programs.
Detailed information on RAC emissions, environmental and health issues are available at the following sites:
SAC County Emission Cover Letter:
Air Quality Issues and Best Management Practices With the Production of Asphalt-Rubber Asphaltic Concrete
NIOSH Health Hazard Evaluation Report:
Hot Mix Asphalt Plants Emission Assessment Report
Stack Emissions with Asphalt-Rubber
LAWS AND GUIDELINES
California
Statute
In 2005, Assembly Bill (AB) 338 was passed. AB 338 requires Caltrans, to the extent feasible, to phase-in the use of crumb rubber asphalt (CRA) on its highway construction and repair projects.at the following levels:
- By January 1, 2007, a minimum 6.62 lbs CRM/tonne total AC pavement to be used.
- By January 1, 2010, a minimum 8.27 lbs CRM/tonne total AC pavement to be used.
- By January 1, 2013, a minimum 11.58 lbs CRM/tonne total AC pavement to be used.
AB939
AB 338 Assembly Bill
AB 338 requires Caltrans to gradually phase in the use of crumb rubber, which is used to make rubberized-asphalt concrete, on state highway construction and repair projects, to the extent feasible. The crumb rubber used is required to be manufactured in the United States, and derived from waste tires taken from U.S. owned and operated vehicles.
Division of Design - Resource Conservation - SB 1346
Summary of SB 876: Five-Year Tire Management Plan
For more information and extensive guidelines visit the following site:
ASPHALT RUBBER USAGE GUIDE
January 2003
Federal
To be determined.
PERFORMANCE
In 2002, Caltrans embarked on a study to evaluate the overall effectiveness of using RAC overlays under a warranty specification in which the contractor would repair (at his own expense) any significant distress that occurs in the first three or five years after construction, depending on the type of the project. The overall purpose of the study was to help provide a "level playing field" for all rubber-modified mixtures that contain a minimum of 15 percent scrap tire rubber. These sections could be constructed using the "wet process" (RAC-G), "terminal blend" (MB), or the "dry process".
Data gathered and analyzed as part of a well-coordinated plan were to be used to evaluate the overall performance and cost effectiveness of the use of RAC.
The performance data collected for the five RAC projects are presented within five separate sections of this report. The report concludes with a summary of the findings thus far and recommendations for continued testing within each of the RAC projects. Overall, the results to date indicate that the RAC projects should generally perform well over the five-year warranty period and the intended 10-year design lives. It is likely that some projects may deteriorate sooner and require more maintenance than others. However, the expectation is that the overall performance should be satisfactory and that RAC overlays are a good candidate for use under a warranty-type specification.
For detailed information on RAC performance refer to the reports available on the Office of Flexible Pavement Materials home page (RAC publications). http://www.dot.ca.gov/hq/esc/Translab/fpm/fpmRAC.htm.htm
Caltrans RAC specifications (39-400 series)
Many local jurisdictions use Caltrans specifications. In southern California, the Greenbook is also commonly used. The Greenbook is available at: BNI Building News
AVAILABILITY
Asphalt Rubber Binder used in RAC is readily available throughout the State. For more information refer to the following sites:
http://rubberpavements.org/
http://www.ciwmb.ca.gov/Tires/
http://ladpw.org/epd/tirerecycling/RAC-REAS.cfm
COST
According to the Rubber Pavements Association (RPA), the cost of RAC has decreased substantially since the patents have expired. The cost is nearly half of what it was in 1985. Currently, crumb rubber costs about $.12 - $.15 a pound. RAC costs roughly $2.50 per square yard (one inch thickness) compared to $1.35/sqyd for conventional Asphalt Concrete (AC). Used in a Friction Course, RAC costs about $2.15/sqyd compared to $1.55/sqyd for conventional mixes.
For detailed cost of the Caltrans RAC projects visit the following site. Click on a year and scroll through to Section 39. There are different costs associated given according to type of RAC. http://www.dot.ca.gov/hq/esc/oe/awards/
| Year |
Conventional AC
tonnes |
RAC
tonnes |
RAC
Percentage |
| 1999 |
7,030,000 |
420,210 |
5.6% |
| 2000 |
7,913,000 |
1,458,800 |
15.6% |
| 2001 |
5,215,000 |
637,272 |
10.9% |
| 2002 |
4,142,000 |
258,805 |
5.9% |
| 2003 |
2,218,000 |
414,160 |
15.7% |
| 2004 |
3,038,238 |
657,700 |
17.8% |
| 2005 |
1,647,984 |
877,704 |
34.8% |
Assumptions:
Passenger Tire Equivalent (PTE) = 20 lbs. per tire
Crumb Rubber Modifier (CRM) = 12 lbs CRM is produced per PTE
2.72 PTE per metric ton of RAC
SPECIFICATIONS
Caltrans specifications for RAC (39-400 and 39-480)
Caltrans Specifications-Procedures: Caltrans takes a new specification through three stages:
Special Provision (SP). First it is an SP where it is used initially on a number of projects.
Standard Special Provision (SSP). After the SP has been used successfully for a period of time, it usually becomes an SSP which means that it is a method approved by Caltrans.
Standard Specification. After the SSP has been used successfully for a period of time, then it usually becomes a Standard Specification, and is included in Caltrans Standard Specifications which is published every four years.
Many local jurisdictions use Caltrans specifications. In Southern California, the Greenbook is commonly used.
What is the Greenbook? The Greenbook, or Standard Specifications for Public Works Construction, is used by the city and county of Los Angeles and 200 other local governments and agencies in the Los Angeles area.
Who Publishes It? It is published by the Joint Cooperative Committee of the Southern California Chapter of the American Public Works Association, and the Southern California Districts of the Associated General Contractors of California.
How Often? It is updated and republished every three years. Supplements are published yearly.
Where Can I Get It? The Greenbook includes both English and metric units, and is available through:
BNI Building News
1612 S. Clementine St.
Anaheim, CA 92802
(714) 517-0970
VENDORS
The (RPA) home page is linked to the following sites:
Advanced RecyclingSciences, Inc.
All States Asphalt
American Recycler
Arizona Department of Transportation
Asfaltomeros, S.A.
Asphalt Rubber TechnologyService
California Tire Report
CEI Enterprises
Columbus McKinnon
CONSULPAV - Consultores eProjectistas de Pavimentos, Lda
Cox Paving Company
Crumb Rubber Manufacturers
D & H Equipment
EAPDD
Granite Construction Company
International Surfacing Systems
Law Engineering LAWGIBBGroup
L.A. Country RubberizedAsphalt Technology Transfer Center
PaveTex Engineering and Testing
Puritan Magnetics
Recycled Materials Resource Center\
Rubber Division, American Chemical Society
Scrap Tire Management Council
Scrap Tire News
Speedie and Associates
Unix Rubber
USEPA - Greenscapes
USEPA - Resource Conservation Challenge
Valley Slurry Seal
Western States Surfacing
SUCCESS STORIES
California
RAC is cost-effective for appropriate applications. A two-inch thick rubberized asphalt concrete overlay can potentially save as much as $50,000 per lane mile when compared to a four-inch thick conventional asphalt overlay.
RAC is durable, safe, and quiet. RAC provides better traction and visibility in wet weather, which may reduce highway accidents. Additionally, many argue that using RAC potentially provides for quieter roadways. Research has shown that noise can be reduced as much as 85 percent using an open graded rubberized friction course. It is unknown at this point if the noise reduction is attributed to the addition of rubber or if it is due to the surface pores associated with open graded pavements.
RAC is environmentally friendly. A two-inch thick resurfacing project uses over 2,000 scrap tires per lane mile. This means that for a one-mile section of a four-lane highway, over 8,000 scrap tires can be used.
What can be done to reduce environmental hazards of our remaining scrap tires?
The good news is that due to the passage of State Assembly Bill 1843 in 2000 and the establishment of the Tire Recycling Management Act, the California Integrated Waste Management Board (CIWMB) is leading a revitalized effort to recycle tire material. CIWMB provides assistance by promoting the use of rubberized asphalt concrete, commonly known as RAC and affectionately referred to as "rubber roads." Rubberized asphalt concrete, a paving product made from aggregates, asphalt cement and reclaimed tire rubber.
The city of Thousand Oaks knows firsthand the benefits of using RAC. The city has been using the product since 1992. To date, Thousand Oaks has used rubber from 1.3 million discarded tires to resurface hundreds of miles of surface streets. The city found that the improvements-increased skid resistance, reduced road noise, improved riding qualities and imperviousness to water-have made the use of RAC cost effective and more desirable than traditional asphalt concrete.
Thousand Oaks is not the only city that has used RAC. The CIWMB awarded more than 60 grants totaling $4.2 million between January and April of this year alone. Many of these grants help first-time or limited-RAC users, including San Clemente, Fremont, Rancho Cordova, Brea, San Fernando, Galt, Ripon and Nevada City, to name just a few. Individuals, businesses, local governments, universities, school districts, park districts, and qualified California Indian tribes are also eligible to apply for the grants.
RESOURCES AND WEBSITES
The CIWMB is mandated to regulate and manage waste tires within the state. The Legislature recognized the need for waste tire management and passed the California Tire Recycling Act in 1989. To further strengthen waste tire management, the Legislature passed Senate Bill (SB) 876 in 2000 to augment the California Tire Recycling Act. For more information, read the Overview of Tire Management in California.
Rubberized Asphalt Concrete Grants (SB 1346)
This grant program provides funding to local governments for rubberized asphalt concrete (RAC) projects. The application period for the fiscal year 2005-06 is now closed. The Board awarded funding to the recommended applicants at its April 2006 Board meeting. The application period for the fiscal year 2006-07 cycle is anticipated to occur in September 2006.
Targeted Rubberized Asphalt Concrete Incentive Grants
This grant program also provides funding to local governments for rubberized asphalt concrete (RAC) projects. The fiscal years 2005-06 and 2006-07 application is now available. Applications are being accepted on a monthly basis.
Setting up a new concrete and asphalt recycling plant requires certain State and local permits, such as air and water, and zoning.
Where Can I Get Help? Businesses starting or expanding into recycling activities may get financial, technical, marketing, business and permitting assistance from the "R-Team" at CIWMB, at (916)341-6526.
Air Permits: The local air districts may be concerned about nuisance odors and various emissions, and may require processors to spray materials with water to control dust. Locate your local air district by calling the Air Resources Board at (916) 322-2990 or by checking their Web site at
Water Permits: The Regional Water Quality Control Board may require a permit for the facility depending on feedstock and location. Look up your regional board in a local phone book under State Government, Water Quality Control Board.
Special Note: Portions of the Environmentally Preferable Purchasing Best Practices Manual were borrowed or adapted from the Environmentally Preferable Purchasing Guide published by the Solid Waste Management Coordinating Board of Minnesota.
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