Concrete vs. Hotmix (asphalt)

[Darkchylde]

I love concrete surfaces. Besides the fact that some stretches last seemingly forever (admittedly under light traffic), the whirring noise is great for gauging speed without having to check the speedometer, and the sound of the car running over the expansion joints actually helps keep me paying attention to the road.

A lot of people don't like some of the older concrete surfaces in Louisiana, but some of them (especially I-55) make for adventurous drives.

[Hellfighter]

I like concrete surfaces because of both the noise (it sounds so cool) and the fact that if a road has concrete, it most likely was reconstructed.

[Marc]

For me it depends. I really like the new porous asphalt that a good portion of the SE U.S. is using these days. Other advantages the porous stuff gives you is that the costs the same as regular asphalt and lasts longer than regular asphalt. Even still though, it doesn't last as long as concrete.

Houston is a city of no asphalt. Even neighborhood streets are all concrete. I don't remember when I drove on asphalt last. It's been a good while. I'd be okay with concrete, but Texas uses grooved/scored concrete which makes a god-awful high pitched whistle. On top of that, they use a continuous pour without slabs/joints, so there's no other sound to help take away from the whining noise. If they used slabs, I'd like it better.

In my opinion though, whatever they type of surface the road is made of, bridges should ALWAYS be concrete. Bridges are expensive to replace and asphalting a bridge only means you have to resurface it more often, putting more strain and weight on the structure. Texas does this on all asphalt freeways and I've never understood why. If a bridge is originally concrete, why would you add a layer of asphalt on top? That's just more weight the structure has to carry.

[Michael]

I thought I was the only one who liked the whistling noise, but I guess not!  I must not be as weird as I thought!

[vdeane]

I love the noise on concrete.  It's probably why most of my favorite road segments are concrete.

One reason why the bridge may have asphalt over it may be that the DOT is too lazy to repair it properly and so just puts asphalt on it to cover the problems.  Happens with roads too; very common in NY (though NYSDOT has been reconstructing some interchanges with concrete).

[jdb1234]

I also love the noise on concrete.

Here in Alabama, we have not had any concrete construction in 30 years (I-459 was the last concrete-built freeway in Alabama).  Ironically, the concrete section is in better shape than the asphalt sections that were resurfaced not to long ago.

Down in Florida, the asphalt highways tend to stain white, making it very hard to see.

[UptownRoadGeek]

I'm mixed, but I guess I like asphalt more.  I hate the tha-thunk tha-thunk tha-thunk of Louisiana concrete, but I love the whistle of the concrete in Houston.  As far in seeing pavement markings in my area when it rains you can't see anymore on asphalt than you can on concrete because the water sits up instead of draining, even on bridges.  Louisiana has recently restriped all of the highways in my area so now between every white stripe there are 5 or 6 reflectors, so at night and in the rain you see the reflectors and you fell it when you cross.  Sort of like Botts dots.

[Scott5114]

Count me in as one who likes the concrete whistle. I mainly get my concrete fix from Kansas, as Oklahoma's concrete freeways were mostly done before scored concrete was invented.

OKC's concrete freeways have some interesting properties. On each expansion joint there are three small patches of concrete approximately where the tires cross (making six per lane on each joint). I think I read on WSDOT's site that those patches conceal "dowel bars", which I guess make the concrete stronger by holding it together. Also, each white stripe has recently had a black stripe painted after it. I'm guessing that's to make it easier to see when the sun angle/weather conditions would otherwise make it impossible to see.

[Tomahawkin]

Is the Porous Asphalt the kind that soaks in Rain in order to help miminize the ponding effect on the road the runoff rain comes from the backside of tire erosion during downpours?

[Bryant5493]

^^ I think you're correct.


Be well,

Bryant

[Snappyjack]

I am a concrete fan myself. The noise, the look, everything. Can't get enough of it. Here in NY, almost all of I-88 is concrete(although near Binghamton, it has been resurfaced with asphalt. I am very glad the Thruway between exits 39 and 40 is being reconstructed with concrete. I wish the whole thing was like that.

[Michael]

^^ I wondered if they were going to do that!  I live in Weedsport, so I see the construction all the time.  I guess I don't have to post a new thread now!

[Snappyjack]

Yeah, last time I drove through there, I glanced over to the other lanes and it definitely looked like concrete to me. Sure enough, I went on the Thruway website, looked up the project info, and confirmed it.

[wytout]

Well we have very few concrete stretches left here in CT (closest to me is a small portion of I-84 around manchester that's probably been there since the old alignment of CT-15/wilbur cross highway. Overall it's held up ok, but does have some asphalt patches in it here and there).  I find concrete has a nostalgic factor to it, and for that reason I like it.  But for driving, you can't beat fresh asphalt.  Of course after a year or two, it's not fresh asphalt anymore, and it's all cracked and full of potholes anyway.

[vdeane]

Yeah, last time I drove through there, I glanced over to the other lanes and it definitely looked like concrete to me. Sure enough, I went on the Thruway website, looked up the project info, and confirmed it.

And I drove on it yesterday, so I can confirm that it's definitely concrete.  Now they're reconstructing another portion just east of there, I wonder if that will be concrete as well.

[njroadhorse]

The whistley noise on concrete bridges makes them so epic. 

[Michael]

*thunk-thunk*
*whistle*
*thunk-thunk*

(possibly repeat)

[Bryant5493]

^^  True.


Be well,

Bryant

[mightyace]

On I-65 south of Nashville, the interstate/freeway is asphalt but most if not all of the exit ramps are concrete. 

I'm not sure why this is other than, TDOT doesn't want to work on the ramps that often.

[Stephane Dumas]

I did a trip to Ottawa in 2006 on TCH-417, there was some gaps who replaced asphalt with concrete. A-13 in Laval is done with concrete.

At Asbestos, a town named from the mining extraction of Asbestos in the north of Sherbrooke, they repaved a street with a blend of "asphalt-asbestos" (approximate translation of the French word "asphalte-amiante" chrisotyle to be more precise, a French article mentionned "asphalt-chrysotile http://www.radio-canada.ca/regions/estrie/2009/07/13/003-asphalte_chrysotile_asbestos.shtml http://www.cyberpresse.ca/la-tribune/estrie/200907/14/01-883955-asbestos-pave-sa-rue-principale-avec-de-lasphalte-amiante.php )

also I spotted on Wikipedia, some stuff about "bioasphalt" http://en.wikipedia.org/wiki/Bioasphalt

[jjakucyk]

Interesting question...I would have to say I tend to prefer concrete, but only when it's done right.  Here in Cincinnati there's very little concrete anywhere, though there's a plethora of 1960's era roads that have been overlaid with asphalt.  Interestingly, even some new/rebuilt roads here in the city itself are built as concrete roads but with a 2-3" asphalt wear surface.  I guess the idea is that the concrete will last for a very very long time, providing a stable base for the asphalt which is easier to replace and maintain.  One thing though that they have been doing is making a pad of concrete intended to remain exposed at bus stops, to prevent rutting.  Here's a good example: http://maps.google.com/maps?gl=us&om=0&ie=UTF8&layer=c&cbll=39.148866,-84.43672&panoid=eLXRIn75VcPH0O7doHXW8g&cbp=12,79.72,,0,19.93&ll=39.148792,-84.436841&spn=0,359.990247&z=17

Unfortunately, most of the newer roads around here that are all concrete just plain suck. Part of the problem (at least in my opinion) is that the low bidders cheap out on the surface finishing.  The grooving is done by hand when the concrete is so wet that it gets very bumpy and jarring.  Proper surface finishing is one of the things that makes concrete more expensive, but when done right it makes the road that much more worth the investment. 

There's a few small sections of roads and overpasses around here that use exposed aggregate concrete.  It's not like what you see on residential sidewalks and driveways (which is much more extreme), but it's similar.  Basically, the top layer of cream is removed during the curing process, exposing the medium sized aggregate.  It looks just like an asphalt road that's weathered for several years, except that it's tan instead of gray, and there may be expansion joints.  That seems to be the preferred finishing method by AASHTO because it's just as quiet, if not more so, than asphalt, as well as providing good traction and wear.

One thing I haven't seen mentioned is that older concrete roads can have their life extended quite a bit by diamond grinding.  It's especially useful after extensive repairs, because it evens out all the patches with the rest of the road surface.  I think they even do it on some new roads too (the new I-40 bypass in Greensboro, NC comes to mind).  You can always tell when it's been done because the grooves run parallel to traffic instead of perpendicular.  It's also a lot less noisy.

[florida]

At Asbestos, a town named from the mining extraction of Asbestos in the north of Sherbrooke, they repaved a street with a blend of "asphalt-asbestos" (approximate translation of the French word "asphalte-amiante" chrisotyle to be more precise, a French article mentionned "asphalt-chrysotile http://www.radio-canada.ca/regions/estrie/2009/07/13/003-asphalte_chrysotile_asbestos.shtml http://www.cyberpresse.ca/la-tribune/estrie/200907/14/01-883955-asbestos-pave-sa-rue-principale-avec-de-lasphalte-amiante.php )

Paving a road with a mixture of asbestos and asphalt? Are Québécois immune to mesothelioma? 

P.S. A few nights ago, I just noticed the city with that name in the road atlas, but I didn't think they'd pave their roads the same way.

[City]

I am personally varied on Concrete VS Asphalt. It really depends. In cities, I probably would go with paving main arteries with concrete. But when you are in a rural area with low traffic, I say pave freeways and roads with asphalt. AADT can define "Pavement or Concrete?" really nicely. If you use NYC for an example, I say pave all the roads with concrete there. It should be a big no-no for very big cities to have asphalt streets.

But when I am on a rural two laned road with not very many other drivers, pave it with asphalt. It is cheaper and accommodates the needs of the road, you should do it. Unless you are talking about those very remote highways. Pave 'im with concrete, and wait for them to crack up. Many, many years will pass by before it degrades. Alaska? Stick it with asphalt. Or porous asphalt.

Some day, concrete can not even handle the traffic we will have. An AADT of 1,000,000 a day would be disturbing. We'll have to make something new.

But for now, I say use either varying by the various situation that he/she has.

[Marc]

On I-65 south of Nashville, the interstate/freeway is asphalt but most if not all of the exit ramps are concrete. 

I'm not sure why this is other than, TDOT doesn't want to work on the ramps that often.

This is a Tennessee thing. I've seen it all over Memphis. Especially on the newer freeways.

[vdeane]

Here is NY the opposite is done - the only surface streets paved with concrete are a couple intersections that have recently been reconstructed, and all the concrete freeways are at the edges of the suburbs or rural.  Then again, it only lasts 20 years here, so when it starts to decay, the road needs to be closed and ripped up, repaved all the way from the base.