Automotive
Past attempts to use shredded tires as road sublayers were abandoned after underground fires
Early 1990s civil engineering experiments showed reduced frost damage but led to hazardous underground combustion in multiple states.
The short version
- In 1992, Maine tested burying shredded tires under a roadway to reduce frost heaves and recycle waste rubber.
- Similar projects in Washington State and Colorado later experienced underground combustion, reaching internal temperatures estimated near 450 degrees Fahrenheit and releasing hazardous compounds.
- The practice of burying tire layers was abandoned due to fire risks and expensive excavations, though blending ground rubber directly into asphalt remains standard.
Key facts
- In 1992, Maine placed approximately 20,000 shredded tires beneath a 600-foot gravel stretch of Dingley Road in Richmond to test whether rubber insulation could prevent frost damage.[Jalopnik]
- By 1996, tire-supported roadbeds in Washington State and Colorado experienced subsurface heating that cracked pavement and released noxious smoke containing benzene.[Jalopnik]
- Excavating the smoldering rubber from affected roadways required protective equipment and was officially estimated in 1996 to cost between $1 million and $3 million.[Jalopnik]
- The discarded burial technique differs from the ongoing standard practice of blending ground rubber directly into asphalt mixes.[Jalopnik]
What remains uncertain
- The precise trigger of the subsurface chemical reactions was not definitively settled, though theories included oxidation of residual steel belts or internal rubber degradation producing sulfuric acid.[Jalopnik]
Sources
Outlet counts describe coverage, not independent confirmation. Reports may share a wire service or original source.