We had an interesting failure back in 96 when they tried using tires as road bed fill. It started to burn underneath the road.
You Can Burn Rubber On This Stretch Of Road Shredded Tires Used As Fill Have Smoldered And Burst Into Flame, Prompting Closure - Spokesman.com - Jan. 31, 1996
After this article was written it got bad enough that they had little black volcanos of goo erupting through the tarmac. They had to dig up the road and haul it off the shredded tire fill to where it could burn itself out somewhere else.
EDIT: The epicness of this failure is more than I thought. It is cited as case number one in a report on scrap tire fires published in 1998. The road bed cost $1 million to create and $3 million to dispose of and clean up. When tearing up the road, the exposed the shredded tires that suddenly burst into flames
"When the tire chips were exposed to oxygen in the air during excavation, the fire flared up and engulfed the excavation equipment"
LOL
Starts on page 8
http://www.usfa.fema.gov/downloads/p...ons/tr-093.pdf