Perhaps not realized here is that "asphalt" is not just one kind of thing.
There are as many "recipes" for asphalt as there are uses. Race tracks don't
tend to break up because the asphalt used is designed to withstand the high
g-load. When Heartland Park was built in Topeka, a different asphalt mix was
used in the corners than on the straights -- and eventually it was the
straights mostly that developed the big cracks from weathering, but the
cracks were not worsened by race traffic. Parking lots, however, are not
usually anticipated to carry g-loads that even an average asphalt street
corner would endure.
But we "stress" the lot maybe once a month, while that streetcorner turn is
stressed 24/7. Thus lots still usually withstand our brand of abuse because
it is such a minimal amount of the use.
The thing I've noticed, mostly, is lots that are clean generally hold up
well. Dusty or sandy is still clean in this regard, but oily is not. If the
lot has telltale oil patches in all the parking places, those soak into and
soften the underlying asphalt and that is often the first thing to show
cornering abuse when we do events. If the lot has potholes, those are
usually weather-related, not caused by us, but we can sure exacerbate them.
We can turn a little pothole into a big pothole in an afternoon, even on
concrete lots (e.g. Nationals). They may throw a hot-mix patch into a
pothole that will hold up just fine under customer traffic, but we'll tear
that patch out in a dozen passes over it if there is the least bit of
cornering force.
New asphalt also needs time before it can take our abuse. They can pave a
lot with asphalt today and park on it tomorrow, but give it a couple of
months before you autocross on it. Our site is concrete, but it needed a
fairly significant repair last year which was done in asphalt. We had to use
it within a week of being laid down, so the first couple of events the
course was designed to just roll over it, not turning or braking there. By
midsummer it was fine and we could do what we wanted on the patch.
--Rocky Entriken
----- Original Message -----
From: "Carson or Wendy" <dammwood@shaw.ca>
To: <autox@autox.team.net>
Sent: Friday, February 27, 2004 5:23 PM
Subject: need help, civil engineer stuff
> Our landlord has cranked up our daily rental rate for holding
> autocrosses. One of the reasons they give is to cover future replacement
> of the asphalt surface.
> The landlord said they would be willing to lower the rental rate if we
> could find some info regarding the wear on the asphalt surface that
> autocrossing creates. I feel this is negligible but they want proof. I
> have a video of our lot with the type of autocrossing it sees. Does this
> info already exist somewhere? Any engineer's out there want to take a
> stab at it. We have no money to pay for a study, sorry.
> Any help greatly appreciated.
> --
> Carson Damm
> Ft. McMurray, AB
> Canada
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