Why are highways in the US paved with concrete?
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Originally Posted By: Alfred_B
The ones I've seen in Europe are concrete with an asphalt laminate. The concrete is protected and lasts a very long time. The asphalt takes the damage and is replaced every few decades.
Yup, that's how the 400-series roads are. They strip the buggered-up asphalt every once in a while and put down fresh over top of the concrete base.
The ones I've seen in Europe are concrete with an asphalt laminate. The concrete is protected and lasts a very long time. The asphalt takes the damage and is replaced every few decades.
Yup, that's how the 400-series roads are. They strip the buggered-up asphalt every once in a while and put down fresh over top of the concrete base.
Asphalt gets soft in the Texas heat and develops ruts. Then comes the cracks, which develop into potholes.
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Originally Posted By: HerrStig
Concrete holds up better in very warm climates, but as we know, is noisy.
They have made some serious strides with the noise. On the 290 expansion happening in NW Harris County (Houston), they have grooved the concrete is such a way the road noise is reduced by more than 70% (give or take). Massive difference versus plain concrete.
Concrete holds up better in very warm climates, but as we know, is noisy.
They have made some serious strides with the noise. On the 290 expansion happening in NW Harris County (Houston), they have grooved the concrete is such a way the road noise is reduced by more than 70% (give or take). Massive difference versus plain concrete.
Working in the road design industry, the short answer is not all highways in the US are concrete - far from it.
In Minnesota, the Concrete and Asphalt pavement industries work hard to better their products and compete hard against each other.
Concrete can be done very well, and last a very long time. The issue is creating a very solid and well drained base, using stainless steel or epoxy coated dowel bars to connect the slabs, and using a low water content (very stiff) mix of concrete to minimize the migration of water (and salt) into the concrete itself. Add on top of that, the time construct, and cure the surface correctly, and downtime to reconstruct a road can be considerable.
Ultimately, we usually end up selecting a road surface based on a variety factors, including initial construction cost, lifecycle cost, soil conditions, and availability of suitable materials for construction, inconvenience posed by construction, etc. When oil costs go up, asphalt prices do too and makes concrete more viable in more scenarios.
We've come a long way on how we groove the concrete to prevent hydroplaning - newer roads are much quieter than the old way we used to do these. We also can do diamond grinding on older concrete to make them quieter too.
Most of it comes down to what its the expected cost over a design lifespan - concrete with one major repair 1/2 to 2/3rds of the way through life, or multiple mill and overlays of asphalt.
Lots of variations from there, but that's the basics.
In Minnesota, the Concrete and Asphalt pavement industries work hard to better their products and compete hard against each other.
Concrete can be done very well, and last a very long time. The issue is creating a very solid and well drained base, using stainless steel or epoxy coated dowel bars to connect the slabs, and using a low water content (very stiff) mix of concrete to minimize the migration of water (and salt) into the concrete itself. Add on top of that, the time construct, and cure the surface correctly, and downtime to reconstruct a road can be considerable.
Ultimately, we usually end up selecting a road surface based on a variety factors, including initial construction cost, lifecycle cost, soil conditions, and availability of suitable materials for construction, inconvenience posed by construction, etc. When oil costs go up, asphalt prices do too and makes concrete more viable in more scenarios.
We've come a long way on how we groove the concrete to prevent hydroplaning - newer roads are much quieter than the old way we used to do these. We also can do diamond grinding on older concrete to make them quieter too.
Most of it comes down to what its the expected cost over a design lifespan - concrete with one major repair 1/2 to 2/3rds of the way through life, or multiple mill and overlays of asphalt.
Lots of variations from there, but that's the basics.
Another issue with concrete that we see up in Canada is in the winters. We need to use a lower slump,"wetter" mix of concrete to utilize air entrainment. With our freeze/thaw cycles we need small air bubbles in the crete to allow water to expand/contract to minimize popouts. Guess what, that adds cost and complexity to builds.
As a young man and officer in 1919, just after WW I, Eisenhower was part of the US Army team that drove across the US to demonstrate the then-new trucks they had. It was miserable and took two months.
https://www.eisenhower.archives.gov/research/online_documents/1919_convoy.html
Later, he was awed by the German Autobahn system and realized how important they were to Germany as a strategic transportation alternative to rail. The original Interstate Highway System specifications included his vision, shaped by his early experience with US roads, that they be able to support the rapid movement of US Army supplies and equipment. Because a tank, or a missile launcher, is so heavy, the highways were built of concrete, and because the equipment was so large, there were strict requirements on overpass height as well.
What's happened since: re-paving, new construction, expansion, may, or may not, have met those original specifications and intent.
https://www.eisenhower.archives.gov/research/online_documents/1919_convoy.html
Later, he was awed by the German Autobahn system and realized how important they were to Germany as a strategic transportation alternative to rail. The original Interstate Highway System specifications included his vision, shaped by his early experience with US roads, that they be able to support the rapid movement of US Army supplies and equipment. Because a tank, or a missile launcher, is so heavy, the highways were built of concrete, and because the equipment was so large, there were strict requirements on overpass height as well.
What's happened since: re-paving, new construction, expansion, may, or may not, have met those original specifications and intent.
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Can't use asphalt at major airports. It can't support the weight of big airplanes. So, the ramps, taxiways, and runways of major airports are all concrete. Three to four feet thick in some places.
4WD
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Whew - I started reading this and thought: "wait, he's an active pilot 
Kestas
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I've read that, on average, concrete lasts 20 years, asphalt lasts 5. From a longevity standpoint concrete is a no-brainer. Even economically concrete is likely a better choice, considering the labor involved with laying down a surface and tying up traffic less often.
Asphalt is a byproduct of crude oil refining. Gotta do something with it. Maybe that's why we use it at all.
Asphalt is a byproduct of crude oil refining. Gotta do something with it. Maybe that's why we use it at all.
Originally Posted By: 4WD
The new freeway SW Houston:
1) build up the road bed
2) pave with asphalt
3) frame up intense re-bar steel above the asphalt
4) pour about a foot of concrete
Interesting.
In Ohio, I've seen them tear out and replace old Interstates using:
1) Road bed
2) Concrete with re-bar
3) Asphalt
Then, they resurface the road every 5 years or so by grinding off some of the asphalt and apply a new asphalt layer
Only bridges have exposed concerete.
The new freeway SW Houston:
1) build up the road bed
2) pave with asphalt
3) frame up intense re-bar steel above the asphalt
4) pour about a foot of concrete
Interesting.
In Ohio, I've seen them tear out and replace old Interstates using:
1) Road bed
2) Concrete with re-bar
3) Asphalt
Then, they resurface the road every 5 years or so by grinding off some of the asphalt and apply a new asphalt layer
Only bridges have exposed concerete.
4WD
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They had paved asphalt over the concrete many times since the 70's - now ripping it all out - I expect this new system will last longer but asphalt could go over it in a few years ...
So that you can see the beautiful grass growing through the gaps every 5 feet as you 'thump, thump, thump' for the next 20 miles. Or to drown out any and all noise of anything else you might hear while driving.
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I see a mix of concrete and asphalt highways here. I've only noticed concrete on the interstates while lesser highways like highway 6 is asphalt.
I think asphalt is a much cheaper material and much easier to lay down. also appears to last about 1/5 to 1/10 as long. Ed
Asphalt here. Atleast the top layer and in the summer the trucks make 2 grooves.
Originally Posted By: Miller88
Most of the roads here in upstate NY are asphalt. Concrete slabs move around too much during freeze/thaw cycles. We have a few roads that were once concrete and then later paved over and they are real shock killers!
For sure. There's even a stretch of thruway on the way to Rochester that's concrete.
My truck hates it.
Most of the roads here in upstate NY are asphalt. Concrete slabs move around too much during freeze/thaw cycles. We have a few roads that were once concrete and then later paved over and they are real shock killers!
For sure. There's even a stretch of thruway on the way to Rochester that's concrete.
My truck hates it.
It's mostly asphalt around here, although we have some concrete - especially grooved concrete. Up where tire chains may be used, they mostly use concrete because it stands up better to wear. Of course they rarely repave.
I was under the impression that most roads in Europe were concrete because it lasts longer. Still - I though that asphalt repair is cheaper, and concrete basically needs to be removed and totally replaced, while asphalt can typically be removed easily and just laid.
I dealt with an HOA driveway, and we basically got asphalt. I asked about concrete and was told it would cost about 3 times as much. There were some concerns about specific spots where garbage trucks went, and one recommendation was for concrete pads in those specific areas like you might see in a parking lot at a discount store.
I was under the impression that most roads in Europe were concrete because it lasts longer. Still - I though that asphalt repair is cheaper, and concrete basically needs to be removed and totally replaced, while asphalt can typically be removed easily and just laid.
I dealt with an HOA driveway, and we basically got asphalt. I asked about concrete and was told it would cost about 3 times as much. There were some concerns about specific spots where garbage trucks went, and one recommendation was for concrete pads in those specific areas like you might see in a parking lot at a discount store.
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Originally Posted By: totegoat
Concrete driveways are good but concrete highways aren't. Asphalt is much cheaper and easier to repair.
Except it does not last in the South with the summer heat and the zillions of OTRs running across it. Back not many years ago, there were sections of the freeways in Houston where you did not need to steer, you could just climb into the ruts and be on "auto steer".
Concrete driveways are good but concrete highways aren't. Asphalt is much cheaper and easier to repair.
Except it does not last in the South with the summer heat and the zillions of OTRs running across it. Back not many years ago, there were sections of the freeways in Houston where you did not need to steer, you could just climb into the ruts and be on "auto steer".
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