The Great Asphalt Road Conspiracy

[Crossroads Inc.]

So...

The other day I found myself talking to a friend of mine who is a Civil Engineer.
I consider the guy pretty level headed, logical and rational.

We got talking about the roads in Phoenix, and how crappy they are. That it seems every big road is also having to be re-tares, re-surfaced or re-paved. Then he starts going off about how it is all because "Big Oil" bought off a bunch of people in the 50's and got them to go from using Concrete for highways to oil based asphalt. According to him, Concrete roads which was what most of the highways in the country were up until the mid 50's, never had big problems with temperature expansion and rarely if ever needed repaving.

Now, conspiracy aside, I am curious if he is correct. If our cities had roads of Concrete instead of Asphalt would it actually be a big benefit? Would the age of gooey half melted roads in the summer, and massive potholes in the winter come to an end, or would they just be replaced by some new problem?

[The Vortex Empire]

http://en.wikipedia.org/wiki/Road_surface

I don't really know anything about it myself, but some interesting information here.

In the 1960s, rubberized asphalt was used for the first time, mixing crumb rubber from used tires with asphalt. While a potential use for tires that would otherwise fill landfills and present a fire hazard, rubberized asphalt has shown greater incidence of wear in freeze-thaw cycles in temperate zones due to non-homogeneous expansion and contraction with non-rubber components. Also, application of rubberized asphalt is more temperature-sensitive, and in many locations can only be applied at certain times of the year.

One of the major advantages of concrete pavements is they are typically stronger and more durable than asphalt roadways. They also can be grooved to provide a durable skid-resistant surface. A notable disadvantage is that it can typically have a higher initial cost, as well as can be more time consuming to construct. This cost can typically be offset through the long life cycle of the pavement. Concrete pavement can be maintained over time utilizing a series of methods known as concrete pavement restoration which include diamond grinding, dowel-bar retrofits, joint and crack sealing, cross-stitching, etc. Diamond grinding is also useful in reducing noise and restoring skid resistance in older concrete pavement.

So concrete roads are more durable, but more expensive. Dunno about the Big Oil conspiracy aspect.

[Grandmaster Jogurt]

From what I was taught it's a cost-benefit situation depending on the road conditions. In some areas, the extra strength and durability of cement concrete is such that you have to resurface the roads significantly less often and that saves a lot of money over time. However, in areas with common construction or other reasons to dig it up, or where frost heaves strong enough to break cement concrete happen regularly, the roads have to be resurfaced so often that the extra durability will not offset the extra cost.

However, a lot of it also has to do with what is available in resources and funds. For instance, many roads around where I live in Maine would actually be cheaper over the long term to pave over in cement concrete, but there is a lot of inertia for two big reasons. The first is that the up front costs would be high and so the state has little interest in adding that into a contract, and the second is that most of the road construction companies around here run asphalt concrete plants primarily with cement concrete only used for non-surface jobs.

[Zeropoint]

Higher up-front costs of cement concrete is enough to explain it to my satisfaction. Most money-spending groups in the world, be they businesses or governments, seem to be unable to grasp the benefits of paying more now to save money in the long run. Any benefit that doesn't show up on the yearly budget might as well not exist.

[Broomstick]

According to him, Concrete roads which was what most of the highways in the country were up until the mid 50's, never had big problems with temperature expansion and rarely if ever needed repaving.

Your friend has obviously never lived/worked in Michigan, Illinois, Wisconsin or Indiana. The normal summer/winter cycles in those states can chew up concrete roads just fine.

[Isolder74]

According to him, Concrete roads which was what most of the highways in the country were up until the mid 50's, never had big problems with temperature expansion and rarely if ever needed repaving.

Your friend has obviously never lived/worked in Michigan, Illinois, Wisconsin or Indiana. The normal summer/winter cycles in those states can chew up concrete roads just fine.

Not to mention the amount of salt they use in Chicago every year doesn't help much either.

[Kitsune]

According to him, Concrete roads which was what most of the highways in the country were up until the mid 50's, never had big problems with temperature expansion and rarely if ever needed repaving.

Your friend has obviously never lived/worked in Michigan, Illinois, Wisconsin or Indiana. The normal summer/winter cycles in those states can chew up concrete roads just fine.

Expansion gaps is suppose to solve that

[Thanas]

Concrete is also worse when it comes to sound dampening, which is a significant factor in rural communities or inner cities over here.

[Crossroads Inc.]

Thanks for all the feed back...

Obviously there are some benefits to Concrete roads, but it's not a "Miracle cure" Like my friend seemed to think.

[Broomstick]

According to him, Concrete roads which was what most of the highways in the country were up until the mid 50's, never had big problems with temperature expansion and rarely if ever needed repaving.

Your friend has obviously never lived/worked in Michigan, Illinois, Wisconsin or Indiana. The normal summer/winter cycles in those states can chew up concrete roads just fine.

Expansion gaps is suppose to solve that

Oh, don't get me wrong - concrete is obviously more durable in those conditions but it's not invulnerable. Expansion joints help but, seriously, if you're cycling between a summer high of 40C and a winter low of -35C with water and salt thrown into the mix and the substance is subjected to the constant pounding of multi-tons of vehicles every day I don't think we have any road material that's going to last particularly long, and even the longest-lasting pavement will require some form of maintenance and patching.

Obviously there are some benefits to Concrete roads, but it's not a "Miracle cure" Like my friend seemed to think.

Correct.

[Kitsune]

Oh, don't get me wrong - concrete is obviously more durable in those conditions but it's not invulnerable. Expansion joints help but, seriously, if you're cycling between a summer high of 40C and a winter low of -35C with water and salt thrown into the mix and the substance is subjected to the constant pounding of multi-tons of vehicles every day I don't think we have any road material that's going to last particularly long, and even the longest-lasting pavement will require some form of maintenance and patching.

My understanding is that areas of Germany also have a lot of bad weather but the Autobahn is also concrete
Interesting, many interstates in my area of Virginia were concrete but have been paving over them in Asphalt.

[Thanas]

Oh, don't get me wrong - concrete is obviously more durable in those conditions but it's not invulnerable. Expansion joints help but, seriously, if you're cycling between a summer high of 40C and a winter low of -35C with water and salt thrown into the mix and the substance is subjected to the constant pounding of multi-tons of vehicles every day I don't think we have any road material that's going to last particularly long, and even the longest-lasting pavement will require some form of maintenance and patching.

My understanding is that areas of Germany also have a lot of bad weather but the Autobahn is also concrete

Most of them are concrete base with asphalt on top, pictures here. But not all asphalt is equal, there are several types used depending on need.

One interesting piece of building is using pure concrete on the lorry lanes and asphalt on the high speed lanes (the left ones) of some of the heavy-volume autobahns.

[Thanas]

Ghetto edit:


This is the typical concrete with asphalt on top you will see on the vast majority of Autobahnstrecken.

[salm]

Oh, don't get me wrong - concrete is obviously more durable in those conditions but it's not invulnerable. Expansion joints help but, seriously, if you're cycling between a summer high of 40C and a winter low of -35C with water and salt thrown into the mix and the substance is subjected to the constant pounding of multi-tons of vehicles every day I don't think we have any road material that's going to last particularly long, and even the longest-lasting pavement will require some form of maintenance and patching.

My understanding is that areas of Germany also have a lot of bad weather but the Autobahn is also concrete
Interesting, many interstates in my area of Virginia were concrete but have been paving over them in Asphalt.

Some autobahnen are mixed roads where the right lane is concrete and the other landes are alphalt. The concrete lane is where the large trucks drive so they need to be more durable.

[Block]

Wouldn't concrete cause more wear on tires and create less traction on turns or is that only the type the tend to use for surfacing garage floors?

[Grandmaster Jogurt]

That's only if you smooth the surface down as you would for an interior surface. Otherwise, the materials are largely similar being mostly a gravel/sand aggregate bonded by something, in one case asphalt in the other case cement. Either way you'll have a rough surface dominated by the gravel so you should be getting similar wear on the tires and traction.

[Covenant]

One of the things that IS true about american roads is that they're shittily designed and require repeated, continual fixes. As boomstick or any of us other Chicago locals will tell you, road construction is the permanent revolution of any urban environment that sees four seasons and has cars. European roads are better designed, but are more expensive upfront. We don't do it right over here and I assume its because of the costs and the need for us to keep changing where they go. Certainly PARTS of the road are concrete, even in Chi-town. Coming in to congress parkway the whole damn thing is concrete under the visible roads. But having seen how long it took to fix that stupid entrance to Wacker (thank the road gnomes that it finally got fixed, for fuck's sake) I'm not surprised people don't do an all-concrete construction for roads in any city that isn't ultra-firmly established.

[andrewgpaul]

Bits of the M74 south of Glasgow were made of reinforced concrete at one stage. The last time I drove down there before it was rebuilt with tarmac, it felt like driving over corrugated sheet.

In addition, painted road markings don't look as clear, to me; there doesn't seem to be as much contrast between the concrete surface and the paint, although there's probably ways round that.

[Broomstick]

Oh yeah, quite simple really - use the standard road markings, but then outline them in black for greater contrast. I've seen that on both roads and runways made of concrete, it can be quite effective.

Of course, paint also costs money...

[andrewgpaul]

I've seen them, and they still didn't stand out as well to me. Might just be my eyes, though.