Comments on: Let it rain

By: CGHill

CGHill — Thu, 15 Oct 2009 14:06:14 +0000

Asphalt is asphalt. The porosity comes from the process by which it’s applied.

But the usual road goo, washed up by rain, ends up below the road bed, and there’s a barrier to keep it out of the subbase. Theoretically, it’s reduced by 90 percent.

Seattle, I understand, worries about salt in Puget Sound. If there normally weren’t any, I’d worry too.

By: McGehee

McGehee — Thu, 15 Oct 2009 14:01:47 +0000

In Alaska’s defense, during the icy months almost everybody is riding on studded tires. The only time I ever skidded out on ice enough to cause an accident was the one winter I didn’t have them.

My car wasn’t damaged that time, but it had just been repaired from when it had been hit by another driver while it sat in the driveway minding its own business.

By: jenn1964

jenn1964 — Thu, 15 Oct 2009 12:34:11 +0000

Ask Seattle how well the no salt policy works. Isn’t porous asphalt petroleum based? Wouldn’t it exacerbate pollution problems?

By: McGehee

McGehee — Thu, 15 Oct 2009 04:17:12 +0000

Of course, on the Dalton Highway when the (unpaved) surface needs winter maintenance, they apply water.

By: CGHill

CGHill — Thu, 15 Oct 2009 03:35:34 +0000

Poking around this little PDF, I found some slightly different advice:

In northern climates, porous pavements have less of a tendency to form black ice and often require less plowing. Sand and gravel should never be used on porous pavements, although salt may be used on porous asphalt, and commercial deicers may be used on porous concrete.

So maybe the salt isn't so bad after all.

By: McGehee

McGehee — Thu, 15 Oct 2009 03:14:39 +0000

There are certainly challenges to overcome — I hear permeable asphalt can’t be salted, for example, a problem in a region with lots of snow

As I recall, in Alaska (a region with lots of snow — or so I hear) there are no surfaces that can be salted (legally). Thus alternatives are used.

Philly might look into said alternatives.