In article <
billvan-7967C6...@news.shawcable.net>,
> <
fbe938a0-d1e6-41fb...@i14g2000yqe.googlegroups.com>,
> Mary <
mrfea...@aol.com> wrote:
>
> > On Sep 16, 11:57 pm, Veronique <
veroniqueuni...@gmail.com> wrote:
> > > On Sep 15, 7:56 am, Mary <
mrfeath...@a0l.com> wrote:
> > >
> > > > On 9/14/2012 8:44 PM, Charles Bishop wrote:
> > >
> > > > > There used to be a "Concrete Highways are Best" campaign. Does
> > > > > anyone have a concrete highway (2 lanes) nearby? I think there
> > > > > was one through one of my hometowns, though I remember brick as
> > > > > well.
> > >
> > > > Yes, there's a state highway that I often use that's concrete, at
> > > > least in sections. There's also a road that should have been
> > > > concrete: they've put a couple of roundabouts in where there used
> > > > to be intersections, and the weight of the cars turning in a tight
> > > > circle have worn ridges where the tires go. I'm waiting to see
> > > > how the roundabout holds up once it snows and the plows have to
> > > > clear it.
> > >
> > > Maybe the plows will scrape it flat again?
> >
> > More likely dig up the ridges and turn them into rubble and thus
> > create a pothole.
> >
> Here in the zone where it sometimes gets cold, potholes occur when
> asphalt gets cold enough to crack, water seeps in, it expands when it
> freezes, further damaging the asphalt, and vibrations from subsequent
> traffic, especially heavy trucks and such, cause the damaged material to
> collapse.
>
> I don't think I've seen potholes in concrete hereabouts. Do they
> actually occur? Same way? And what causes potholes where it doesn't
> freeze?
I'm guessing the roadway surface gets damaged by falling equipment or
gets chunks dug out by accelerating/braking/turning vehicles, and the
development is furthered by other vehicles hitting the downstream edge or
rain washing away the layers beneath, making the edges unsupported. It
doesn't freeze here often (a handful of times per year, never very hard),
and I don't know the mechanics of pothole development. They do occur
though.