On Sat, Jun 14, 2014 at 7:05 PM, sjard <sjard@emerytelcom.net> wrote:
"Road crews have been known to bury foil-wrapped potatoes under fresh asphalt, then come back and exhume them several minutes later . . . "
Having worked on a road crew, I'm not entirely sure how that would work. Hot mix asphalt comes out of the mix plant at between 450 to 500 degrees fahrenheit, and has to be laid down and shaped before it drops below about 300 degrees. If it drops below about 275, it won't compress properly with the rollers and you have to scrape it back up and usually dump it (it's very hard to reheat properly). It cools rapidly; you've only got about 15 minutes with a 5 ton load from plant to worked before it cools too much.
I'm not sure what you mean by "plant."
When road crews around here work, the asphalt comes to them in regular large dump trucks, then gets tipped into a big, slow-moving, one-lane-plus-wide machine with a large hopper on the back which does the pre-roller spreading. Given our *horrendous* local traffic, there is NO way these dump trucks are making it from a fixed plant somewhere to a roadwork site in only 15 minutes. So those big crawlers must be able to re-heat fairly cool asphalt to application temps.
Assuming this is correct, I can see "accidentally" bleeding a bit of extra hot asphalt off onto the road shoulder, then coming back when it's cooled off to ~275 and shoveling it back into the hopper (minus your lunch).
Richard Aiken
"Never insult anyone by accident." Robert A. Heinlein
"A word to the wise ain't necessary -- it's the stupid ones that need the advice." - Bill Cosby
"We know a little about a lot of things; just enough to make us dangerous." Dean Winchester