The oncomming traffic lane buckled like a little mountain ridge caused by two plates pushing into each other.

The net result on traffic seemed to be that several cars speeding along at 80mph suddenly hit a ramp in the middle of 94 East bound.

I always assumed it was really rare and the cause was that road some times gets laid at much lower temperatures and has to have higher regidity to be able to withstand -40 temps in the winter.

Also a lot of southern highways seem to be concrete. I assume becuase concrete is lighter and reflects heat.

Now I’m really curious. My google-fu is weak though, bring on the engineers!

I’m guessing that cement holds up to snow plows much better than asphalt does. And with its built-in flexibility, asphalt handles expansion from extreme heat better than cement.

But that’s just a guess. Any civil engineers out there know what’s really happening?

I find this really incredible, unless have a lot of shade and perhaps benefit from local valley cooling.

We have a 1930 stucco bungalow with no tree protection (all the old grown trees were hacked down by neighbors years ago) and have a whole house fan- yet, if the temps even flirt with the mid-eighties, it feels like we’re sitting on the blast vent of Hades itself. We’ve never been able to hold out long when the temps start rising in the spring.

I envy your great fortune- or mystical ways with stucco and fans.

*Not and engineer, but I play one on TV.

We used to have one of the first continuously reinforced concrete superhighways – the 495 bypass around Wilmington – that was engineered to expand and contract as a single, miles-long unit. It was rather impressive until the concrete started to break down at the molecular level after a decade or two. Seriously – the State said it was a chemical incompatibility between the aggregates used – http://pubsindex.trb.org/view.aspx?id=424656 – and the cement itself.

I recommend Minneapolis hire new highway engineers, ones who have lived in a place with variable temperatures at some point.

I think this won’t happen unless you have a dark or black surface to super heat a long stretch of road until it expands enough to cause a break.

It isn’t that concrete can’t take the freeze-thaw cycles as well as asphalt (in some regards it does a better job) but that potholes are inevitable in northern climes and repairing concrete pavement is much more complicated (and costly) than repairing asphalt.

Yet, the Edina City Council is concerned with new bike paths!

I’ve lived here four years now and it’s always taken a while–several days of very high temperatures or weeks of just general warmth–for this house to heat up to the point that it becomes uncomfortable. And it’s been cooler than average in Minneapolis right up until last week. (In fact, the downside is that I was still wearing a sweater to work two weeks ago. Outside was pleasant, inside was a touch too cool.) I’ll get hot in here eventually, just not yet. And in Fall, it’ll take us a while to cool down, too.

But yeah, standards are obviously different in different parts of the world. I remember how everybody in Toronto freaked out two or three years ago when they had dry 30° weather with everything from urgent heat advisories to free public pools. This is what happens here when temperatures reach 40°. Never could figure out why the same temperature is more dangerous for people in one region than in another (we don’t have an A/C culture here, so that’s not it ;-).

http://media.publicbroadcasting.net/kera/newsroom/images/3260697.jpg

This is the President George Bush Turnpike, or State Highway 190, north of Dallas. This is my primary route on my commute to and from work. It’s still not repaired because of the extensive damage that was caused to the road and the wall.

Those bumps you hit on concrete roads are expansion joints, thats where the road will expand to in the heat. The picture posted is pavers, not a concrete slab road. That hole in the picture is a tree stump and the damage is due to the settlement of the soil around where the tree stump and root system rotted out. Why does this happen when its hot out? The ground water has lowered, the soil can now settle into the void space left when the water recedes
out of the soil.

Damage to the road surface is a sign of the problem in the roadbed. Concrete is far stronger than the stress created from thermal expansion as long as is it constantly supported by the roadbed, road bed fails then the road fails above it, patch that hole a new one will form since the bed is weak below it. A slab will only buckle if it is restrained,roads are not restrained, they are free to expand laterally either to the sides of the road or into the expansion joints that are place in slabs.