Listed below are recent posts across all of CalRecyle's blogs.
Santa Barbara’s Ortega Ridge Road is no longer in danger of washing away thanks to 80,000 recycled waste tires. Like many paved pathways that curve and bend along with California’s rugged terrain, the ground beneath the road absorbed water in the rainy season - undermining its stability and causing the asphalt to crack, sink, and slide down the hillside. At one point, the road was reduced to just one safe lane.
Now, thanks to an innovative new road repair technique, Ortega Ridge Road is stable, safe, and a model for what’s possible in areas prone to landslides.
A First for California
With grant assistance and technical guidance from the California Department of Resources Recycling and Recovery (CalRecycle), Santa Barbara County rebuilt Ortega Ridge Road in 2019 using more than 80,000 recycled tires that were shredded and processed into Tire-Derived Aggregate (TDA). The highly permeable fill material allows water to drain through it (unlike conventional soil)– avoiding excess weight that often causes these types of roadways to wash away.
The Ortega Ridge Road repair was the first infrastructure project in California to use TDA material in this type of civil engineering application.
CalRecycle Funding Stopped the Cycle of Failure
Santa Barbara County spent decades on this problem. “We were looking for a solution for this continually failing road,” says Chris Doolittle, an engineer geologist with Santa Barbara County. “It had been failing for 20 years at a minimum.” Over and over again, crews tried the more traditional repair technique of laying down new asphalt – one layer after another - only to watch the road degrade again.
“We had a good relationship with CalRecycle and determined this site would be a really good candidate for a pilot project,” Doolittle recalls.
In March of 2018, CalRecycle awarded Santa Barbara County $158,241 in funding from its Tire-Derived Aggregate Grant Program to purchase the recycled tire fill material. Armed with research from the University of California San Diego, which provided engineering data for the project design, CalRecycle worked alongside the county and engineering contractor GHD Services to design and construct a more eco-friendly and long-lasting repair on a 225-foot section of Ortega Ridge Road.
Tire-derived aggregate, made from 810 tons of California waste tires, was used to backfill a retaining wall composed of large, rock-filled welded wire baskets (called gabions) to replace failed soil and provide lateral support to the reconstructed embankment. The repair resulted in a more permanent repair, saved the county permitting time, money for easements, construction costs and expensive road materials.
“CalRecycle provided expert support,” notes CalRecycle senior waste management engineer William Heung. “As a result, public works was able to open a safe, stable roadway to the public more quickly and inexpensively than traditional methods, with the environmental benefit of reducing the number of used tires buried in landfills.”
There’s an Award for That!
The Ortega Ridge Road repair earned the 2020 Outstanding Local Streets and Road Repair Project award from the County Engineers Association of California (CEAC).
“What we want is to see something that is out-of-the-box thinking and innovative,” explained CEAC President Rick Tippett, also the director of transportation for Trinity County. “What this award is intended to do is share success, so other agencies will take those ideas back to their communities.”
Project leaders are hopeful a recognition like this will encourage other local cities and counties to consider the use of TDA and this groundbreaking engineering technique to improve local infrastructure and protect public safety. “We would like to see more of this type of project around the state,” says Heung. “It is a superior alternative material to other products out there and a great use for California’s scrap tires.”
Longer Lasting Roads with Little Environmental Impact
Tire-Derived Aggregate is a smart, cost-effective way to repurpose some of the 51 million waste tires that Californians generate every year. Beneficial uses for this material include:
- Lightweight, permeable backfill that’s lighter than gravel and more permeable than soil
- A low-cost option to reduce train noise. When placed under tracks, TDA reduces the vibration and noise that is often a nuisance to those living nearby.
- Retaining wall backfill, particularly in areas prone to landslides. Because of TDA’s lightweight properties, retaining walls can be designed using less reinforcing steel.
- Landfill gas collection trenches. The high porosity of TDA makes it an excellent material for filling landfill gas collection trenches that transport methane, hydrogen sulfide, and carbon dioxide.
CalRecycle’s Tire-Derived Aggregate Grant Program supports projects that use recycled waste tires in place of conventional construction materials for civil engineering applications such as retaining wall backfill, landslide stabilization, vibration mitigation, and various landfill uses. The unique engineering properties of shredded waste tires allow for free-draining, lightweight, and typically less expensive solutions for these types of projects.
Posted on In the Loop by Chris McSwain on Jul 20, 2020
- Since 2011, CalRecycle has awarded $5,582,126 in TDA grants to 28 projects statewide.
- Grants are funded through a portion of the $1.75 fee consumers pay on each new tire purchased in California.
- For more information about CalRecycle’s waste tire management grants, including application criteria and maximum award amounts, see our Tire Recycling, Cleanup, and Enforcement Grants webpage.
- Get direct notifications about funding availability, applicant and project eligibility, and application due dates by joining CalRecycle’s Tire-Derived Aggregate listserv.
Tire fires of past decades could take months to extinguish, while emitting smoke thick containing cyanide, carbon monoxide, and other toxins.
Until 19 years ago, countless illegally dumped tires polluted our state. Large piles of old tires sometimes even caught fire in the hot California sun. These tire fires put off toxic smoke containing cyanide and carbon monoxide. Because a fire can continue to burn deep inside a pile of tires after the top layer appears extinguished, firefighters struggled to put out these smoldering blazes that emitted thick, black plumes of toxic smoke that sometimes burned for months.
California turned to recycling to solve the problem of tires:
- Catching fire
- Clogging waterways
- Filling with water that bred disease-causing mosquitoes
Where can we put 51 million tires a year?
California’s 35 million registered vehicles generate 51 million used tires every year. To manage this constant flow of vulcanized rubber into the waste stream, California passed the Tire Recycling Act in 1989, which created the Tire Recycling Program. After a series of devastating illegal tire pile fires in 1998 and 1999, the law was strengthened in 2000.
To prevent illegal stockpiles of tires, the state has:
- Permitted tire storage facilities
- Enforced used tire storage and management laws
- Developed recycled tire product options
To find new uses for more than 82 percent of 51 million worn-out tires a year, CalRecycle constantly innovates and evaluates safety studies. The department awards grants and loans to businesses and public entities to expand the safest markets for waste tires.
Different styles of playground cover are a common use of recycled tires.
Across California, companies are producing tire-derived products made from recycled tires, including:
- Playground surfaces
- Flooring, including rubber mats for gyms
- Path cover
- Accessibility ramps
Where the rubber becomes the road
For more than 30 years, ground-up, recycled tires mixed with asphalt have produced cost-effective, durable, and environmentally friendly binder in concrete road cover. Overall, about 2.7 million tires have gone to paving California’s roads.
Tire rubber makes up only about 1 percent of rubberized asphalt concrete. The asphalt binder absorbs the rubber into it, reducing its ability to break away as a microparticle. These streets last about 50 percent longer than roads made from asphalt alone.
Many local governments have used tire-derived aggregate in place of conventional construction material for civil engineering projects to:
- Backfill retaining walls
- Stabilize hills to keep them from slipping into landslides
- Absorb vibrations
- Fill in land for other reasons
This tire material helps solve a variety of civil engineering challenges because it drains better and costs less than other lightweight, mixed material building aggregate.
“Tire-derived aggregate requires minimum processing and reduces the need for mining (like other lightweight fills) in facilities that generate greenhouse gases,” said William Heung, CalRecycle Senior Waste Management Engineer for the Materials Management and Local Assistance Division.
Tires saved millions on California transportation
Local governments used this tire material to expand rail systems for both the Bay Area Rapid Transportation (BART) and the Metropolitan Transportation Agency in Southern California. The cushioning rubber from tires absorbs vibrations underneath the tracks.
Along with keeping about 500,000 tires from going into landfills, these two projects saved BART and MTA millions of dollars.
Tire material stabilizes a retaining wall on a hill that prevents mudslides in Santa Barbara.
A recent innovative road project in Santa Barbara used tire material to stabilize a retaining wall located on a hill. Because the tire material won’t degrade even when wet, engineers expect it to support the retaining wall more effectively and help prevent mudslides that can happen when water washes away soil on a hill. (View video.)
Keeping tires from trashing California
California’s population will continue to grow, so our efforts to expand tire recycling must keep pace.
Over the last few years, through its grants and loans, CalRecycle has funded rubberized road concrete and other tire material projects to prevent millions of waste tires from ending up illegally dumped or in landfills.
CalRecycle explores potential tire products as we work to reach the state's zero waste goals while preventing tire fires that pollute our air with poisonous smoke.Posted on In the Loop by Syd Fong on Feb 18, 2020
Yuba County is home to the latest construction project to use recycled waste tires to patch up damaged roadways. Last month, 430,000 tires were utilized as filling material to repair multiple roads destroyed by recent landslides.
CalRecycle awarded the county $439,636 as part of the Tire-Derived Aggregate Grant Program, which funded both the purchase of the recycled tire material and the repair work.
Tire-Derived Aggregate (TDA) is made from shredded scrap tires and is used in a wide range of construction projects. These uses include retaining wall backfill, lightweight embankment fill, landslide stabilization, vibration mitigation, and various landfill applications.
The material is lightweight and cost-effective, and it drains well in wet conditions.
As an added bonus, recycling tires diverts them from landfills and illegal dumpsites. Currently, California generates more than 40 million waste tires per year.
Take a look at this video to see the recent Yuba County TDA project in action.Posted on In the Loop by Syd Fong on Oct 7, 2019