Probably not*. The "old asphalt roads" are 90-96% aggregate (rocks). The asphalt is really just a flexible binder for the harder stuff. Also, the lighter volatiles have long since evaporated from the asphalt cement, so it won't readily light. Come to think about it, the asphalt cement is, cut with water, emulsifiers and other additives to improve application and durability.
*I did some calculation to determine the heat content of asphalt concrete roads as compared to wood, and I've decided that both may be useful, depending on context:
- 1. Decent hardwood (think birch, not hickory) has a comparable Btu content as asphalt concrete:
- --Seasoned Birch: 6.95 kBtu/lb, 162.5 kBtu/ft^3 (these are based on cord density, not wood density);
- --Old Asphalt Road: 8.82 kBtu/lb, 64.9 kBtu/ft^3 (based on in-place density, 5% cement content & 30% additive content).
- 2. I will guess that wood will release the heat more quickly, while the aggregate in asphalt concrete will store heat and release it slowly over time.
- 3. Wood and "old roads" will require approximately the same handling. The wood needs to be cut, split and stored while the asphalt needs to be broken up, then the (potentially useful) aggregate will need to be (re)moved.
- 4. The asphalt cement will need an existing hot fire to start. The ignition temperature of asphalt is ~900F, so the entire mass including the aggregate will will absorb a great deal of heat before it starts contributing anything.
- 5. profit?
I set out to demonstrate that your comment wasn't very useful, but it looks like old asphalt roads may, in fact, be useful for keeping warm, with the caveat that some other material will be needed to start (and maintain) an asphalt concrete fire.