beyond burning tires: the case for crumb rubber …infohouse.p2ric.org/ref/30/29463.pdfbeyond...

Beyond Burning Tires: The Case for Crumb Rubber Modified Asphalt

Prepared by Resa Dimino for Environmental Action Foundation

Introduction

Americans throw away 275 million old tires, more than one tire for every man, woman and child, each year. The majority of cast-off tires, now numbering as many as three billion, sit around the country in stockpiles, often stretching as far as the eye can see. Ugly to look at and clumsy to handle, these tires can also ignite into uncontrollable toxic fiies and serve as breeding grounds for rodents and mosquitoes that spread diseases.

The enormity and the visibility of the scrap tire problem has fueled an unfortunate drive for quick-fix solutions. As a result, the vast majority of “recycled” tires are burned for fuel (see Figure 1). Proponents of so-called “tire-derived fuel” argue that the high energy content in used tires makes them ideal candidates for burning. Yet, far greater net energy and environmental benefits are achievable by reprocessing tires into other valuable commodities.

In fact, ground up (or “crumb”) rubber from old tires can be used to make such useful commodities as garbage cans, welcome mats, athletic tracks, carpet backing, gaskets and asphalt. Not only can products made from crumb rubber provide a valuable end use for scrap tires, they can also save resources by displacing the raw materials that would have otherwise been used. Encouraging this higher quality recycling can provide economic development benefits as well. Communities that are now tire dumping grounds can house reprocessing facilities, bringing with them jobs and income.

This Action Paper is designed to educate policy makers and their constituents about the alternatives TO stock- piling and burning scrap tires. It profiles successful efforts to develop sustainable markets for this potentially valuable

Where Tires Are Going

Split/Punched 1% Retread/ Used

Crumb Rubber 2% commodity. And, in particular, it calls for coordinated action

at the state and federal levels to promote crumb rubber modified asphalt as a technology with a proven track record 51 %

and by far the greatest near-term potential to boost markets for scrap tires. Source: Scrap Tire Managemeni Council, 1994

Figure 1 ~~ ~~ ~~~

Environmental Action Foundation, 6930 Carroll Avenue, Suite 600, Takoma Park, MD 20912

Tire Burning: Resources up in Smoke

were reported to the U.S. Environmental Protection Agency (EPA) in 1989 alone. Burning tires emit carcinogenic poly-nuclear aromatic hydrocarbons, carbon monoxide, sulfur dioxide, nitrogen oxides and hydrochloric acid. In addition, because tires melt as they bum, these fires create an oily, liquid leachate (pyrolytic oil) that can contaminate surface and groundwater.

Tire stockpiles present a constant threat of dangerous fires. Eighty seven scrap tire pile fires

Tire fires can be quite costly to contain and clean up as well. The notorious Winchester, VA, tire fire burned for seven months in 1984 and cost the U.S. Environmental Protection Agency @PA) $1.8 million to contain. And that did not even cover the costs of fighting the fire, it simply paid for efforts to minimize contamination. Even after EPA’s expenditures, the site remained on the Superfund national priority list. A fire in Hagersville, Ontario, cost $1.5 million to extinguish. The cleanup, closure and monitoring costs are expected to reach an additional $3 million. If the 87 fires in 1989 were all that costly, the costs of containing and cleaning up the tire fires for that year alone might reach $300 million.

Burning tires for energy has been touted as a sound approach to getting tires out of stockpiles and into productive use. Tires are an attractive fuel for cement kilns, pulp and paper mills and some electric utilities, primarily because the fuel costs have been low. Many states provide rebates to users of tires for energy, making them an even cheaper fuel source. In addition, in the case of cement kilns and industrial boilers, a relatively small investment is required to shift from coal or coke to tires.

While burning tires in a controlled atmosphere, like an industrial boiler or tire-to-energy plant, may be safer than exposed tire pile fires, it is not beyond environmental reproach. Proponents of tire incineration argue tires burn cleaner than coal and petroleum coke, releasing less sulfur dioxide and nitrogen oxides. Burning tires, especially whole tires, can, however, increase emissions of the more toxic heavy metals, volatile organic compounds (VOCs), dioxins and furans. “In effect, substituting tires for coal trades pollutants you can see and smell for those that are invisible. That doesn’t make it safe,” explains Clean Water Action’s Selena Schmidt, who is fighting a Pittsburgh, PA, cement kiln’s bid to switch to tire burning.

From Waste To Raw Materials: Recycling Markets

Finding new uses for old tires avoids the environmental risks associated with tire burning and also helps conserve valuable resources. Up to ten million tires every year are discarded by consumers before they are completely worn and sold as used by tire dealers. In a more widespread practice, 30 to 33 million tires, mostly from trucks, are retread every year. Many state and local governments, as well as the federal government, have set purchasing guidelines that favor retreads in order to encourage this high-value end use for scrap tires. Unfortunately, with the advent of low-cost imported tires and the demise of snow tires, the once-thriving passenger car market for retreads is now quite limited.

Some discarded tires are split or “punched” for use in products such as gaskets, shoe soles, and dock bumpers. EPA estimates that markets for these types of products will demand roughly 3 million tires per year.

Whole or chipped tires are also used in some civil engineering applications, including road embankments, lightweight fill and crash barriers. These applications are important for a few reasons. First, the rubber provides performance benefits like resilience and insulation. Second, civil engineering


applications can use a significant amount of tires. One project by the University of Maine and the Army Corps of Engineers used a layer of tire chips as an insulator to reduce frost penetration on a gravel road. (A 6OO-foot long portion of road used about 20,000 old tires.) Third, this type of project can use tires that have been stockpiled and are too contaminated for higher value applications like crumb rubber. Although preferable to burning, these applications have the disadvantages of not adding much value to tires and not allowing the rubber to be recycled again.

The equivalent of 19 million tires are used in crumb rubber products every year. In this process, tires are shredded and then further refined to remove all metals, fibers and contaminants. Each tire contains about 10 or 12 pounds of usable rubber. There are about 15 crumb rubber manufacturing facilities in operation. The vast majority of the feedstock for crumbing facilities are not scrap tires, but buffings, a by-product of the retreading process. Buffings make up three-quarters of the 19 million tires going to crumb facilities; only 5 million scrap tires are currently used in crumb. Industry analysts say that is changing, and since the market for retreads is limited, the supply of buffings is not expected to grow. Any increase in crumbing capacity will increase the demand for scrap tires.

Crumb rubber can be used in rubber sheet and molded products, such as floor mats, mud flaps, and railroad crossings. A small amount of crumb is further refined for use as “reclaim” rubber in new tires. Together, these applications use the equivalent of about 13 million tires. There is significant growth potential in these end-uses. However, since crumb rubber is used in a variety of small and diverse markets, it is difficult to develop public policy to support them directly.

The remainder of the supply of crumb rubber, roughly six million tires worth, is used in asphalt. Extensive studies have shown that crumb rubber modified (CRM) asphalt, or rubberized asphalt, can increase the life and improve the performance of roads. Yet, the use of CRM asphalt is still not widespread. More than 30 states routinely use crumb rubber modifiers, but in relatively small applications. Less than one percent of paving material used now contains crumb rubber. However, the growth potential in this area is dramatic. EPA states: “Crumb rubber additives for pavements and combustion are the two categories of scrap tire utilization that have the greatest potential of using a considerable proportion of the tires generated each year.” Having surveyed the industry, the American Council for an Energy Efficient Economy estimates that CRM asphalt is suitable for 20 to 40 percent of all paving applications.

As with other materials, focusing on market development for high-value uses will help draw tires into a variety of recycled products. As the recycling market with the largest near-term growth potential, rubberized asphalt will improve our nation’s roads and develop the tire crumbing infrastructure. This infrastructure, in turn, will enhance the quality and lower the price of crumb rubber, thus increasing its access to other end use markets.

Crumb Rubber Modified Asphalt: The Basics

Crumb rubber was developed as a modifier in the 1960s to improve the performance and durability of pavements. Asphalt pavement contains two primary components: a binder and an aggregate. The asphalt binder is a petroleum product; the aggregate is stone,

Materials Used in Asphalt Pavements, 1994

~~

Aggregate 45 1.2 million tons

Asphalt Binder 28.8 million tons

Total Asphalt 480 million tons Pavement

burce: National Asphalt Paving Associatior Figure 2

usually whatever is locally available, including granite, limestone or shale. Crumb rubber modifier (CRM) can either be mixed with the binder in a “wet” process to make Asphalt Rubber; or it can be


mixed with the aggregate in a “dry” process to create Rubber Modified Asphalt Concrete (RUMAC). Given the massive amount of material used each year on our nation’s roads (see Figure 2), CRM asphalt has the potential to reduce our dependence on petroleum products and stone mining.

Crumb rubber modified asphalt has demonstrated exceptional engineering characteristics and improved performance over conventional asphalt pavements in many applications. Although specific properties vary according to mix design, in general, rubberized asphalt can build a longer-lasting road requiring less maintenance. CRM asphalt is more durable and elastic, which reduces weather-related damage in hot, wet and cold weather. For example, potholes are formed when water leaks through cracks in a pavement’s surface and then freezes and thaws, weakening the roads structure. Because CRM asphalt is more durable and elastic, it cracks less, leaks less, and results in fewer potholes. It also contains anti-oxidants that make pavements resistant to aging. The most extensive experience in using CRM asphalt is in Arizona, California and Florida.

Nonetheless, not all CRM asphalt projects have out-performed conventional asphalt. This can be attributed to insufficient transfer of effective mix designs and specifications for various road conditions. In a 1993 Report to Congress, the EPA and the Federal Highway Administration (FHWA) conclude: “The failures generally reflect inexperience with CRM technology in project selection, design engineering, and construction decisions.”

Detractors point to CRM asphalt’s higher initial material cost as a barrier to widespread use. Properly designed and applied, the premium for CRM asphalt materials runs around 20 percent higher than conventional asphalt. Yet, case studies have shown that, because of the performance benefits, CRM asphalt can have lower life-cycle costs. For example, a subdivision in Kansas City, Missouri, was repaved with CRM asphalt at a significant savings to the county. The original plan to use three inches of conventional asphalt would have cost Jackson County $360,000 and taken 60 days. The project was completed in only 2 days using one inch of CRM asphalt, and cost only $170,000. The contractor provided a four-year guarantee on the project, and in that four years it required no maintenance.

In addition, the price of rubberized asphalt is dropping due to the expiration of patents on the process and the development of a generic, unpatented RUMAC mix. The cost of Asphalt Rubber, for example, has declined by almost 50 percent since the patent expired in June 1992. Materials costs are expected to continue to drop as more contractors learn how to use rubberized asphalt, larger scale projects are undertaken and more tire crumbers come on line.

Rubberized asphalt presents economic development opportunities as well. The process of col- , lecting, transporting and processing tires for use in asphalt adds to the local economic base and adds

value to the material. “[Rubberized asphalt] takes a waste product with negative value and turns it into a product worth 17 cents per pound,” explains Joe Cano, of International Surfacing, Inc., and former engineer for the City of Phoenix. Once this technology takes hold in most of the states, it will become the biggest and most environmentally sustainable market for scrap tires.

The Institute for Local Self-Reliance estimates that a recent federal initiative to promote rubberized asphalt (see next section) would create up to 6,000 jobs in and around 385 small-scale tire crumbing facilities. These facilities would add up to $200 million in revenue to the economy. In addition, the process yields a product with significant performance benefits. The jobs created, value added, and superior- productmake crumb rubber modified asphalt an attractive “green” technology.


Federal Action on Tire Markets

Section 1038 of the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) directed state Departments of Transportation to spend a percent- age of their federal highway dollars on asphalt pavements containing old tires. Since passage, implementation of the law has been bogged down in attacks by some state transportation officials and conventional asphalt pavers. To date, the minimum use requirement in ISTEA has not been implemented.

In its original form, Section 1038 would have required states to use 5 percent of their 1994 federal paving budget on CRM asphalt. The law increased the requirement by 5 percent per year, to 20 percent by 1997 and years thereafter. The provision would have provided a stable market for CRM asphalt, ensuring that this “green” industry developed. At full implementation, in 1997 and after, state rubberized asphalt projects would have used 80

The Red Herrings

Opponents of crumb rubber modified asphalt fre- quently try to undercut the technology’s environmental credentials by raising questions about its impact on worker health and safety, and whether the material can be recycled. Neither critique is supported by current research.

CRM asphalt is sometimes mixed at higher temperatures than conventional asphalt, but no study has shown significant increased exposure to harmful chemicals for workers on rubberized asphalt projects. According to an EPA and FHWA report to Congress: “Based on the findings of seven projects in the US and Canada, the currently available data collectively indicate that no obvious trends of significantly increased or decreased emissions can be attributed to the use of CRM in [hot mix asphalt] pavement produc tion .”

Claims that rubberized asphalt pavements cannot be recycled as readily as conventional asphalt pavement are also unfounded. Both rubber modified asphalt concrete and Asphalt Rubber have been recycled successfully. There is no evidence that crumb rubber modified asphalt pavements perform any differently than conventional asphalt in the recycling process.

million tires per year. In addition, it would have developed the infrastructure for tire crumbing, creating an incentive for more companies to get involved and opening other markets to crumb rubber.

Section 1038 also directed the Federal Highway Administration to remove CRM asphalt from the experimental materials list and conduct a technology transfer program to ensure that CRM asphalt was applied appropriately and successfully. In addition, EPA and FHWA were directed to conduct a study on the impacts of rubberized asphalt on pavement recyclability, worker health and safety, and performance. The report was issued in June 1993 finding no reason to restrict the use of CRM asphalt based on these concerns.

Despite the demonstrated benefits of CRM asphalt, the traditional paving interests and some state highway officials continue to oppose the mandate in ISTEA. “Our position is that rubber may be benefi- cial in some cases, but it has to be based on engineering and economics,” explains Dick Morgan, Vice President of the National Asphalt Pavement Association (NAPA), the trade association leading the charge against Section 1038.

Even officiais in some states that have had great success with rubberized asphalt oppose the ~ ~~~ -~


mandate. “I don’t think we should be mandated to use [crumb rubber modified asphalt]. We need to use engineering characteristics to choose our materials,” says Randy West, an official at the Florida Department of Transportation. Florida has developed its own process for including crumb rubber in asphalt and has voluntarily chosen to use CRM asphalt in all of its road surfaces.

Organization

National Asphalt Paving Association

Opponents question the technology’s cost-effectiveness. “The use of crumb rubber in asphalt has not [always] proven to be cost effective,” charges Jim Sorrenson of the Federal Highway Adminis- tration. Transportation officials claim they already have a $30 to $50 billion shortfall in funding to meet transportation needs, so they should not have to pay a higher up-front cost for rubberized asphalt. On the other hand, by paying a bit more for CRM asphalt, those came governments will avoid the costs of disposing of and managing scrap tires. Such costs include tip fees that average $1.50 per tire, liabil- ity for tire stockpiles, and tire f’i cleanup costs. At full implementation of Section 1038, the avoided disposal cost alone would save local governments $149 million. One study done for the State of New Jersey estimated that the costs of incorporating tires in asphalt, from the point of generation until the rubber meets the road, is only $2 per tire.

Membership Interest

Conventional Longer lasting roads paving and road-building roadbuilding contractors. contractors Also, very cosy with

mean less work for

asphalt suppliers.

The minimum use requirement in Section 1038 was designed to stimulate demand for CRM asphalt in an industry that has been using the same materials for 60 years, and lags behind its European counterparts. In fact, the benefits of Section 1038 have been recognized in Europe, where use of the technology is widespread, An official with TOSAS, a major European paving contractor, wrote in a letter to NAPA: “We think your campaign against the use of CRM in hot mix asphalt is counter productive in view of the performance and cost benefits and the disposal of [tires] in the U.S.”

Yet, some fear that Section 1038 has actually hindered development of the new technology. Consultant Gary Cooper reports that before 1991 the crumb rubber modified asphalt industry was growing at a rate of about 25 percent per year. Since the passage of ISTEA, that growth has slowed dramatically. He argues that the mandate has put states and asphalt pavers on the defensive. Instead of giving states an incentive to research how to use rubberized asphalt properly, it is ‘‘making people research why they shouldn’t have to use it,” says Cooper.

“Having [CRM asphalt] shoved down people’s throats in the name of environmentalism has caused a backlash,” explains Gary Anderton, Civil Engineer for the Army Corps of Engineers. Florida’s West agrees, noting that his colleagues in other states “never got past being angry” about the mandate and recognized rubberized asphalt’s benefits, as Florida has.

West Virginia Transportation Secretary and Chair of the American Association of State Highway Transportation Officials (AASHTO) Task Force on Section 1038, Charlie Miller, sums up his colleagues’ concerns: “The bottom line is, [state transportation officials] know, f i t hand or anecdotally, of failures and it scares the bejesus out of them.”

Section 1038: The Opponents

The Asphalt Institute

They make more money when they sell more asphalt; crumb rubber cuts into the market share for asphalt binder.

I Large petroleum companies

American Association of State Highway and Trasportation officials

Very close relationsips

officials. years of collaboration and funding.

Figure 3


“The problem is that not all the states have the resources and time to do the research, and it won’t work unless it’s done properly,” concludes Bob Eaton, of the Army Corps of Engineers Cold Regions Research and Engineering Laboratory. “I am convinced that it will work most of the time if it is designed and constructed properly.” Unfortunately, states working in this area often end up reinventing the wheel, rather than learning from each others successes and failures.

Some point to the Federal Highway Administration’s technology transfer program as the magic bullet. “CRM asphalt will take off with or without ISTEA. The question is: When?” de- clares Michael Blumenthal of the Scrap Tire Management Council. He argues that the performance benefits and long-term cost effectiveness of rubberized asphalt make it a “better mousetrap.” “What I think we need is technology transfer,” he adds, “Departments of Transportation need to under- stand what they are working with.”

Others argue that a federal technology transfer program may not do the trick. Gary Cooper, who consults on rubberized asphalt projects, argues that in his experience, “most states will not accept other states’ experience” as proof that the material performs well. The Corps of Engineers’ Bob Eaton agrees, but also suggests that some states may accept the results of research funded by FHWA if it were done by a well-respected research team. FHWA is about to issue a $2.5 million research project that will look more closely at issues of cost, performance, recyclability and worker health and safety and recommend procedures for design and construction. Those recommendations will likely not be final before 1999. Whether the team chosen for the FHWA research project will be outside of the grips of the politics of this issue is still in question.

But there is more to this debate than just cost, performance and aversion to mandates. “The politics in this business are very strong,” says Barry Takallou, of TAK Consulting Engineers. Longer lasting roads mean less work for NAPA members. If they don’t start to get into crumb rubber projects, at full implementation of ISTEA’s rubberized asphalt provisions NAPA members stand to loose up to $3 billion. Contractors often build cheap, short-lived roads and then get paid again to repair or re-lay them. A recent article in Readers Digest sums up the problem: “In many European countries, contractors must guarantee their work for up to five years after completion. When they mess up, they fix it up -- a concept foreign to American road builders.” (It should be noted that many state laws require low-bid contracts, which are antithetical to long-term guaran- tees.)

NAPA and its road-building contractor membership provide significant campaign contribu- tions to Members of Congress, including Rep. Bob Can (D-MI), chair of the subcommittee on transportation appropriations. Rep. Can was responsible for the 1994 funding block on Section 1038, which resulted in an effective moratorium on implementation. He is attempting to do the same in 1995.

In addition, the revolving door between FHWA and NAPA has hampered that agency’s interest in meeting its requirements to implement Section 1038. “Whoever is the head of the Fed- eral Highway Administration, their next job is at NAPA,” muses Takallou, “They’re not going to go against their future boss.” Indeed, NAPA’s Morgan is the former Director of FHWA.

Well before the dverii of Section 1938, and until tday , supporters of crumb rubber modified asphalt within the federal government found their efforts squelched by powerful special inter-


Recycled Tires for Better Roads Coalition

Southwest Public Recycling Association, Solana Recyclers, Earth Circle Recycling, Northem California Recycling Association. Ecology Action of Santa CNZ, Garbage Reincamation, California Resource Recovery Association, Californians Against Waste, Connecticut Recyclers’ Association, Scenic America. EESI, Public Citizen’s Critical Mass Project, USPIRG. American Public Health Association, Friends of the Earth, American Institute of Architects, National Recycling Coalition, Environmental Defense Fund, Institute for Local Self Reliance, Amalgamated

Transit Union, Institute of Scrap Recycling Industries, Defenders of Wildlife, ACEEE. American Planning Association. Rails to Trails, Govemment Purchasing Project, National Wildlife Federation, Sierra Club, Surface TmspoItation Policy Project, Florida ITDRA, Iowa

Recycling Association, Environmental Law and Policy Center of the Midwest, Neighborhood Capital Budget Group, Chicagoland Bicycle Federation, Illinois Recycling Association, Bethel New Life, Center for Neighborhood Technology, Urban Harvest, Tire Technology, Citizens

for Appropriate Rural Roads, Kentucky Resources Council, South Central Recycling Association of Massachusetts, Warren Recycling Committee, Mass Recycle, Center for Ecological Technology, North and East Brookfield Recycling Committees. Sturbridge Recycling

Committee. Hispanic Office of Planning and Evaluation, Boston Recycling Coalition, Claudia Thompson Consulting, Good Neighbor Project, Chesapeake Bay Foundation, Maryland PIRG, Maryland Recyclers Coalition, Ecology Center of Ann Arbor, Recycle Ann Arbor, East and West

Michigan Environmental Councils, Genesee County Area Recycling Coalition, Citizens for Altematives to Chemical Contamination, Clean Water Action Michigan, Michigan Recycling Coalition, Recyclers of Ingham, Eaton and Clinton Counties, Michigan Environmental Council, St Paul Neighborhood Energy Consortium. Gulfcoast Recycling, Montana Environmental Information Center, Montanans for a Healthy Future,

Montanans Against Toxic Buming. Conservation Council of North Carolina, SunShares, Association of New Jersey Recyclers, Natural Resources Defense Council, NYPIRG, New York Environmental Planning Lobby, Hudson River Sloop Clearwater, Association of Ohio

Recyclers, Ohio Citizen Action, Environmental Health Watch, College of Wooster Recycling Coordinator, Recycling Advocates, OPIRG, Association of Oregon Recyclers, Organizations United for the Environment, Pennsylvania Clean Water Action. Audubon Society of Rhode

Island, South Carolina Recycling Market Development Advisory Council, South Dakota Resources Coalition, Virginians for Recycling, Virginia Recycling Association, Coalition for Jobs and the Environment, Washington Citizens for Recycling, Citizens for a Better Environment, Associate Recyclers of Wisconsin, West Virginia Solid Waste Management Board, National Environmental Health Association, Association of

American Wheelman, Delaware Clean Air Council, National Tire Dealers and Retreaders Association, as well as members in Arkansas, Alabama, Califomia, Mountain States, Georgia, Kansas. Louisiana, New England, Maryland, Missouri, North Carolina, Ohio, Texas

/

ests. In 1986, the EPA tried to issue a procurement guideline for crumb rubber modified asphalt. The guideline was pulled due to complaints from states and FHWA. EPA tried again in 1994. Again, the issue was judged too controversial for agency action. The US. Army Corps of Engineers recently delayed publication of a CRM asphalt user’s guide and specifications for at least a year. Another Corps project to develop a new CRM asphalt mix, which had been funded by the FHWA’s Strategic Highway Research Program and showed great potential in the lab, has lost its funding for the next stage of field testing.

Recognizing the importance of federal leadership to promote rubberized asphalt, a coalition of more than 100 public health, local government, environmental, recycling and industry representative has come together to advocate federal initiatives in support of crumb rubber modified asphalt. The Recycled Tires for Better Roads Coalition (see member list above) has committed to pressure Congress and the federal agencies to implement Section 1038 and promote rubberized asphalt in general.

Lessons from the States

In spite of the stalemate at the federal level, where Section 1038 has been bottled up by Con- gress, many states continue to make considerable progress in the use of crumb rubber modified asphalt. Recycling advocates should look toward different approaches to securing a market niche for this promising green technology in their own states and to following the lead of those innovative states and locali- ties that have already embraced CRM asphalt. In New Mexico, for example, the state has evened out the economics of incorporating tires in asphalt. A law passed this spring appropriates roughly half of the state’s tire fund, raised through an advance disposal fee on tires, to offset the higher initial costs to local governments to use rubberized asphalt.


Four case studies of other state and local efforts to promote CRM asphalt follow below.

Phoenix, Arizona

The City of Phoenix has the longest and most comprehensive experience using crumb rubber modified asphalt in the United States. Under the guidance of city engineer Charles McDonald, the city pioneered the use of asphalt rubber in the early 1960s as a method to increase the durability and cost- effectiveness of roads. Called the McDonald, or Asphalt Rubber Process, this method mixes 75-to-80 percent asphalt cement with 20-to-25 percent crumb rubber from old tires at high temperatures to create an asphalt rubber binder.

Over the past 30 years the city has used Asphalt Rubber extensively in a wide variety of applications. The fiist tests, in 1964 and 1965, used asphalt rubber as a stress absorbing membrane (SAM) on roads and airport runways that had experienced extensive cracking. The elastic properties of Asphalt Rubber proved to help stabilize badly cracked pavements and prevent reflective cracking. Shortly after these trials, the city began to routinely use Asphalt Rubber SAM’s.

The city then developed a method to use asphalt rubber stress absorbing membrane interlayer (SAMI), which is applied to the cracked surface and then covered by an asphalt concrete overlay. This method allowed existing pavements that had become structurally unsound to be rehabilitated, instead of replaced, leading to substantial savings for the city. The end result, according to former city engineer, Joe Cano: “It costs the taxpayer less per mile.” The city estimates that Asphalt Rubber provides maintenance-free roads for 12 to 15 years, as opposed to two-to-seven years for conventional pavements. Therefore, the long-term economics favor incorporating crumb rubber. In one case, an asphalt rubber SAMI was placed on a road in poor condition in 1971. The road was scheduled for total reconstruction in 1973. That road remained in service, maintenance free, until 1991.

In the late 1980s, Phoenix engineers also began to use an Asphalt Rubber concrete overlay as a surface course on roads. In 1989 alone, Phoenix used 70 miles of Asphalt Rubber concrete overlay, consuming 250,000 old tires. Although long-term performance data is not yet available, based on the performance to date, city engineers expect that the Asphalt Rubber overlay will be more durable, ex- tending the life of the pavement by as much as 15 years. The overlay has reduced oxidation and deterio- ration of the pavement, increased skid resistance by 30 percent, and improved the riding surface.

Contact: Joe Cano, International Surfacing, Inc., (800) 528-4548.

The State of Florida

In December, 1993, Florid8 Governor Lawtofi Chiles arnrrourrced that the state would make using rubberized asphalt “standard operating procedure” in virtually all of its surface courses. The practice is expected to consume about 20 percent of the tires generated in the state. In addition, local governments are expected to follow the state’s lead and use another 20 percent of scrap tires.

Engineers at the Florida Department of Transportation (DOT) have developed their own process for incorporating crumb rubber. It uses relatively small amounts (.4 to 20 percent) of a very fine rubber

lay rubberized asphalt at a reasonable cost and with relative ease of application. The cost to the state is which is mixed at Inwr temperatmes thm Asphalt Rubber. n e Fix was de\depd tc a k w the state tG


roughly 20 percent more than conventional asphalt now, and engineers expect that premium to drop to 10 percent in the near future. They predict the roads will last, on average, 25 percent longer.

Before making the leap to rubber roads, the state studied the potential effects of the new mix on worker health and safety. In a Tampa area project, the state DOT worked with the National Institute of Occupational Safety and Health, the Occupational Safety and Health Administration, EPA and Westinghouse to perform the evaluations. The study concluded that there was not a significant increase in worker exposure (over threshold levels), as a result of the inclusion of crumb rubber. The state also studied the recyclability of CRM asphalt and found that the crumb rubber had no “undesirable impact” on pavement recyclability.

Contact: Randy West, Florida Department of Transportation, (904) 488-5596.

The State of New Jersey:

The New Jersey Departments of Environmental Protection (DEP) and Transportation (DOT) have been working together for four years to address the use of recycled materials in highway construction projects. Under a contract funded by the DEP’s market development and research budget, the DOT established a Recycled Materials Task Force, made up of DOT and DEP representatives, as well as contractors and representatives of the Federal Highway Administration.

The New Jersey task force was created in 1990 to meet the DOT’S requirement under 1987 state law to revise its purchasing specifications to include recycled materials. In addition, in May, 1993, then- Governor Jim Florio issued an executive order on recycled product procurement that requires the DOT to surpass ISTEA requirements and use rubberized asphalt in 40 percent of its paving projects by 2001. “[The task force] has been very, very constructive in accomplishing what we were instructed to do,” says Henry Justus, a DOT official and chair of the task force.

Justus reports that the task force has been helpful in quick problem solving and in creating an “excellent rapport” with state environmental officials. Although they have not issued specifications yet, the state is actively testing four different types of CRM asphalt. They report no immediate problems on any of the test sections. The DEP contract also covers some of the research and development costs for these projects. In a related project, with funding from the EPA, the state has hired TAK Consulting Engineers to perform a full-cost audit of crumb rubber modified asphalt and two other tire recovery options to determine the true costs, from generation to end use, of these options. The cost-sharing and communication that has been pioneered in New Jersey has helped to get beyond any resentment DOTS feel for being “burdened” with scrap tires. It has encouraged the DOT to jump the hurdles facing the technology, not inflate them. It also brings some unbiased players into the fray.

Contact: Henry Justus, New Jersey Department of Transportation, (609) 530-2307

The State of California

California is a leader in the use of crumb rubber modified asphalt. In 1993 the state Department of Transportation (Caltrans) used a total of about 500,000 tons of CRM asphalt on 25, or about 7 percent: of the state’s paving projects. Local and County governments in California did at least as much paving with Asphalt Rubber, bringing the state-wide total use to over one million tons. That eats up a


whopping 1.7 million tires. Caltrans reports the number of Asphalt Rubber projects grows every year.

Caltrans began experimenting with rubberized asphalt in 1978 as a method to improve pavement performance in the snowy regions of the state. The first trial used FloMix, a type of dry process. Later, Caltrans tested Asphalt Rubber and PlusRide. These trials proved that rubberized asphalt out-performed conventional asphalt. The f i s t application in a non-snow region was in 1985. Since 1988, Caltrans has used Asphalt Rubber binder exclusively in its CRM applications.

In 1983, Caltrans experimented with both PlusRide and Asphalt Rubber at thicknesses reduced by over 50 percent. After three years all of the thin “control” sections had failed, but the PlusRide and Asphalt Rubber thin overlays showed no signs of distress. Since then, reduced thickness has become standard operating procedure for crumb rubber modified asphalt projects, making them much more cost effective. In addition to saving in material costs, the reduced thickness pavements use less energy and labor. Reducing thickness can also avoid costs related to reconstructing curbs, sewers, drains, signs, guardrails, etc.

When the passage of ISTEA removed crumb rubber modified asphalt from the Federal Highway Administration’s list of experimental materials, Caltrans began to routinely use Asphalt Rubber in rehabilitation projects. Today, the agency recommends at least one strategy using Asphalt Rubber for almost all road rehabilitation projects. Caltrans issued crumb rubber modified asphalt thickness design guidelines in 1992.

Caltrans has done some testing on worker health and safety which found that emissions on Asphalt Rubber projects were not beyond permissible levels. Nonetheless, workers on seven of the 25 Asphalt Rubber projects in 1993 complained about the fumes. In response a task force has been formed to study the issue and report by the end of 1994. Caltrans is about to begin a project to recycle sections of PlusRide, Asphalt Rubber and conventional asphalt. This project will look at workability and performance, as well as emissions from the recycling process.

Contact: Jack Van Kirk, California Department of Transportation, (916) 227-7300.

Conclusion

These experiences demonstrate the potential that crumb rubber holds to both build better, longer- lasting roads, and provide a high-value end use for tires. They point to two key strategies for moving to action: 1. Finding creative means to offset the higher initial materials costs associated with crumb rubber modified asphalt; 2. Identifying leadership within the state, through an environmental department or Governor’s office, to facilitate the process in cooperation with the DOT.

Whether or not Section 1038 survives today’s anti-regulatory mood in Washington, states will play a critical role in ensuring a foothold for rubberized asphalt. If Section 1038 heads toward implementation, pressure at home will help ensure that the states meet their obligations. If Section 1038 does not survive, a state-by-state advocacy approach can keep this promising technology moving forward, and build momentum in support of federal action for the future.


.................... .........................................o . What You Can Do! . . . . . . . . . . . . . . . . . . . 1. Write to Your Members Of Congress: It is time that the Federal Government support, not undermine,:

2. Meet With Your State and Local Departments of Transportation: Find out if they are

the development of green technologies like rubberized asphalt. Call Environmental Action Foundation for an update on the federal scene. . using crumb rubber modified asphalt. If they aren't, encourage them to try it. Encourage communication : . . between environmental and transportation agencies. . . . . . . . . . . . . . . . . . .

3. Promote Policies that Support Rubberized Asphalt: Procurement policies can create a stable market for CRM asphalt. Cost-sharing programs, through grants, advanced disposal fees, or other funding mechanisms can help ease transportation official's concerns.

: . . . wise draw public attention to this promising technology. . For more information on tire recycling, rubberized asphalt or other recycling issues contact: :

4. Publicize the Issue: Write an Opinion piece for your local newspaper, send out a press release, or other

Environmental Action Foundation 6930 Carroll Avenue, Suite 600

Takoma Park, MD 20912 (301) 891-1100 . .

.....e.............. .......................................... Resources on Tires and Crumb Rubber Modified Asphalt

Doug Howell Environment and Energy Study Institute 122 C Street, NW, Suite 700 Washington, DC 20001 (202) 628-1400

Michael Alexander Northeast Recycling Council 139 Main Street, Suite 401 Brattleboro, VT 05301 (802) 254-3636

Coordinates the Recycled Tires for Better Roads Coali- tion. Lead environmental group in the legislative battle.

Studies tire recycling and CRM asphalt use in the northeast; organized a meeting with state DOT'S and DEPs in the region.

Bill Eyring Center for Neighborhood Technology 2125 West North Avenue Chicago, IL 60647 (3 12) 278-4800

Gordon MacDougall and Sean Reed Rubber Pavements Association 3 12 Massachusetts Avenue, NE Washington, DC 20002 (202) 544-71 11

Working at the local level and nationally to promote CRM Trade association for asphalt rubber producers, contractors and asphalt as an example of more sustainable economic development.

crumb rubber manufacturers. Knowledgeable on players and processes related to &e tec!mo!ogyc Lead in the legislative battle.

Curtis Ravenel Byron Lord National Recycling Coalition 1101 30th Street, NW, Suite 305 Washington, DC 20007

Chief, Pavements Division, R&D Federal Highway Administration 6300 Georgetown pike, HNR 20

(202) 625-6406 M c ~ , VA 22101-2296 (703) 285-2062

NRC will develop, by 1995, a "best practices manual" to provide companies with information on how to use available technologies to recycle scrap tires.

Key in mplementing FKW-A's research and technoiogy transfer programs.


beyond burning tires: the case for crumb rubber …infohouse.p2ric.org/ref/30/29463.pdfbeyond...

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