This article was originally printed in the City of Colorado Springs Green Greetings.
On June 8, the City of Colorado Springs Street Division received an Excellence in Recycling award for their leadership role in recycling waste tires. Starting in 2006, the City began an experimental resurfacing program using Permeable Friction Course Terminally Blended Tire Rubber Asphalt (TBTRA) that to date has used a total of 226 tons of liquid tire rubber from approximately 45,500 recycled tires. Over the last four years, 78 lane miles of roads in Colorado Springs have been paved with TBTRA. Beginning in 2010, the City’s TBTRA paving program is planning to exclusively use waste tires generated in Colorado. Not only has the City’s TBTRA program been well received by local citizens, the positive buzz has led other communities across the state to try incorporating TBTRA into their paving programs.
Even in tough economic times, the City Street Division and Pikes Peak Rural Transportation Authority (PPRTA) have continued to support the use of TBTRA as part of the City’s street maintenance program. While the primary user benefit of TBTRA is extending pavement life, the product has also proven to have significant safety and other benefits, including improved road conditions in rain and snow storms, noise reductions of up to 3 decibels, ability to filter out of contaminants from storm water runoff, and an exceptionally smooth driving surface.
The Colorado Springs Street Division changed its experiment in 2007 from using mixes with 10 percent tire rubber content in the oil to 15 percent tire rubber content. This further increased the amount of waste tires that could be used by the program. On average, 2.1 waste tires are used per ton of asphalt mix; 291 tons of TBTRA are typically used per lane mile.
Within Colorado, tire rubber asphalt historically had a poor reputation due to durability issues and environmental pollution in the manufacturing process. Street Division Manager Saleem Khattak, assisted by Bob Syme of the PPRTA maintenance program and the Arizona Department of Transportation, researched these problems and found ways to mitigate them. When challenges arose in the field, City staff and their partners identified the causes and documented them with pictures, turning the lessons learned into a technical presentation now used to help their staff and contractors, as well as other communities, develop best practices for the application of TBTRA in Colorado. This proactive information sharing has increased the chances that others will experience positive outcomes when trying TBTRA, further encouraging its use.
One of the unique elements of Colorado Springs’ use of TBTRA has been extensive scientific documentation and testing. By investing in noise studies, pavement condition analysis, and testing of TBTRA over a long period of time using different percentages of rubber, various rock sizes and underlying surface conditions, the Street Division has quantifiably demonstrated TBTRA’s benefits. This testing and documentation has helped to overcome industry hesitation and has changed the perception of TBTRA’s viability in our state.
The City plans to continue using TBTRA where appropriate and economically feasible, as it has shown to be good for the City, the environment, and the roads that the Street Division safeguards for our community. However, building an economy of scale through multiple users is critical to the future development of regional manufacturing of the terminally blended oil, more tire recycling plants in Colorado, a subsequent reduction of costs for the product, and the overall reduction of waste tire stockpiles in the state.
The Colorado Association for Recycling brings together individuals and leaders in business, education, nonprofits, and state and local government to take action to turn greater amounts of waste into resources. Their annual award program recognizes governmental entities, individuals, companies and organizations for their excellence in recycling. The Outstanding Government Recycling/Diversion category is awarded to a public agency that leads by example, creating programs that efficiently increase recycling and waste diversion.
