A chip seal job is the
poor man's paving. Instead of paving a road with
asphalt and
concrete, which are
amazingly expensive,
counties and
municipalities will often use chip sealing. It's much
cheaper, and has many of the advantages as a
real paving job.
Here's the
lowdown:
The
road to be sealed is usually
gravel. The road is first
paved so there's a
nice cap (rounded form, being higher in the center).
A
penerating oil is applied. This is that super
black,
sticky shit that you see sprayed on
highways. It
ruins everything it touches. However, this
oil holds the road together
nicely. It's applied, then allowed to
dry for
24 hours. After a day, it is pretty hard.
After a day has passed, crews come in an apply a second layer of penetrating oil. While the oil is still
hot (it's sprayed out at about 230F), a
chip spreader follows immediately behind the
applicator truck and
dumps the chips on. Around here, the chips we use are
pink granite chips. They're hard little rocks that make a nice driving surface, but suck ass for
rollerblading.
Following about 300' behind the chip spreader are a series of
rollers. They
pack the chips into the oil, where hopefully they'll stay. Three or four rollers are used. The rollers are
positioned to form a
half V shape -- like
ducks and
birds fly. That way the each
overlap the other's tracks.
And that's about it. To chip seal on mile of gravel road costs about $100,000. And they call this cheap.