Indiana's Concrete Pavement

[digitalphiltv]

This is kind of loaded...but I've thought and googled on this rare-to-occasionally for a few years now... What's the reason behind Indiana using so much grooved concrete pavement, where other states use asphalt? I prefer the concrete, but sometimes I wish for asphalt when I get tired of the noise from driving over the grooved pavement. This is a mystery to me, which has puzzled me for years now... Why do some of the concrete bridges in Indiana have concrete extending a couple hundred feet either side of the bridge? And why is the pavement also concrete for a couple hundred feet either side of (and underneath) some overpasses on an otherwise asphalt roadway? Why put grooves in the concrete anyway?

[AsphaltPlanet]

Grooves provide friction between the roadway and tire to improve traction.  At overpasses, I suspect the reason for a short sections of concrete is to maintain height clearance at an overpass. Adding 90 mm (3-1/2") of asphalt over a concrete highway is a significant profile increase.

[Mdcastle]

The overall cost of a concrete roadway can be cheaper. Sometimes asphalt is used because it's cheaper overall, and sometimes just because it's cheaper up front. Indiana and the Midwest have a harsh climate, hard soils and are far from major oil refineries but have plenty of limestone for making concrete, and thus use a lot of it. Florida presumably has softer soil and is closer to refineries, and has a gentle climate, and uses a lot of asphalt. The only places I've seen concrete in Florida are downtown Orlando and Miami.

There's a technique for soft soils now to put down asphalt and then concrete on top of it, but that was after I-394 was built; the center section was asphalt over soft soils, and each end was concrete over hard soils.

Concrete on either side- I've seen it here where a bridge is rebuilt, they'll rebuild the road a bit on either side and will use concrete. As for under overpasses they might have put an asphalt overlay on the rest of the road, but couldn't under the bridge do to clearance issues.

Grooves are to rough it up to provide skid resistance. A newer techinque is to use weighted astroturf or burlap rather than a fine metal rake, this produces a more tolerable low rumble instead of a high pitched whine.

[agentsteel53]

At overpasses, I suspect the reason for a short sections of concrete is to maintain height clearance at an overpass. Adding 90 mm (3-1/2") of asphalt over a concrete highway is a significant profile increase.

that is the precise reason in California; I'd imagine it is the same elsewhere. 

I feel like the difference is only about 2 inches, though.

[kkt]

Even if the initial asphalt is only 2" thick, it has to be repaved pretty often, and they just put a new layer over the top.  A couple of repavings down the road and the height becomes a problem.

[AsphaltPlanet]

That problem is pretty easily avoidable by simply milling the asphalt off of the concrete prior to repaving. It is possible to cold mill concrete pavement as well prior to paving it but that does have an effect on the pavement structure which could be negative.

[Alps]

Concrete on either side of the bridge is not actually the bridge, it's "approach slabs." That should point you in the right direction on that. Concrete below the overpass is because that's the original pavement that was there, and asphalt is typically added on top of concrete rather than replacing it. Adding asphalt under the overpass would reduce the clearance by 3" which can be a difference maker for some trucks.

[kphoger]

There's a technique for soft soils now to put down asphalt and then concrete on top of it, but that was after I-394 was built; the center section was asphalt over soft soils, and each end was concrete over hard soils.

This is called white topping, right?

[mukade]

Adding asphalt under the overpass would reduce the clearance by 3" which can be a difference maker for some trucks.

I can't say for sure, but I thought they did it to increase the bridge clearance by two or three inches (or whatever). If I remember correctly, they did the under bridge concrete work across the state in a relatively short span of time so I just assumed that is why they did it. When Indiana resurfaces highways, as with most every other state, they mill the old pavement down before laying the new surface so there should not result in any reduction in clearance.

[digitalphiltv]

Thanks guys... I had suspected some of this, although I did not consider the clearance issue underneath bridges.

[thenetwork]

Concrete on either side of the bridge is not actually the bridge, it's "approach slabs." That should point you in the right direction on that. Concrete below the overpass is because that's the original pavement that was there, and asphalt is typically added on top of concrete rather than replacing it. Adding asphalt under the overpass would reduce the clearance by 3" which can be a difference maker for some trucks.

And don't forget that in the colder climates, there could be several inches of packed snow/ice on the roadway in the winter that reduces the clearance even more at times.

[formulanone]

...sometimes I wish for asphalt when I get tired of the noise from driving over the grooved pavement.

Not to completely dissect your question here, but I wonder if cutting the cement with seemingly random grooves, rather than fixed-width and fixed-spaced grooves, might reduce road noise. There's spans or brides in which the noise is particularly grating.

I only suggest this idea because repetitive "road noise" can be cancelled out somewhat by tire tread patterns which also use non-fixed width tread blocks, grooves, and sipes that are of varying sizes (although they appear similar, usually the inner or outer tread blocks on recent tires are not equally sized. (It should be noted this isn't typically not found on "cheaper" tires or heavy-duty truck tires.)

On the other hand, there's not much incentive to use extra time and expense on this, because there's no real financial benefit, post-construction...but just an idea that suddenly popped in my head.

[Revive 755]

There's a technique for soft soils now to put down asphalt and then concrete on top of it, but that was after I-394 was built; the center section was asphalt over soft soils, and each end was concrete over hard soils.

This is called white topping, right?

White topping, IIRC, is a type of resurfacing where concrete is the material being laid on top of the existing pavement instead of asphalt.

I have heard of some places placing asphalt under concrete when the pavement is being placed from the ground up on new or complete removal and replacement projects.

[vdeane]

It is possible to reduce noise by changing the grooves.  NY does this with newer concrete and has re-grooved some older concrete (I still remember with great sadness when the Thruway did this between I-490 and NY 332, especially since the noise was unique and not the usual whine).  The noise never bothered me, but with the exception of I-390 between Mount Morris and the Thruway, NY hasn't had many (none that I traveled with any kind of regularity at least) concrete segments longer than 5 miles until recently; they pretty much all were in the Southern Tier.

[jwolfer]

The overall cost of a concrete roadway can be cheaper. Sometimes asphalt is used because it's cheaper overall, and sometimes just because it's cheaper up front. Indiana and the Midwest have a harsh climate, hard soils and are far from major oil refineries but have plenty of limestone for making concrete, and thus use a lot of it. Florida presumably has softer soil and is closer to refineries, and has a gentle climate, and uses a lot of asphalt. The only places I've seen concrete in Florida are downtown Orlando and Miami.

There's a technique for soft soils now to put down asphalt and then concrete on top of it, but that was after I-394 was built; the center section was asphalt over soft soils, and each end was concrete over hard soils.

Concrete on either side- I've seen it here where a bridge is rebuilt, they'll rebuild the road a bit on either side and will use concrete. As for under overpasses they might have put an asphalt overlay on the rest of the road, but couldn't under the bridge do to clearance issues.

Grooves are to rough it up to provide skid resistance. A newer techinque is to use weighted astroturf or burlap rather than a fine metal rake, this produces a more tolerable low rumble instead of a high pitched whine.

most urban areas in Florida have concrete interstates.  I-95 reconstuction in Brevard County was concrete too

[Interstatefan78]

Here in New Jersey grooved concrete pavement is only found on I-287 from exit 47-66 and driving this stretch has a different whine on your car, but  most roads use ungrooved concrete pavement like I-280 from exit 15-17 and I-78 from exit 52-58 and driving these highways on their concrete section makes a standard noise   

[NJRoadfan]

Here in New Jersey grooved concrete pavement is only found on I-287 from exit 47-66 and driving this stretch has a different whine on your car

It used to be MUCH louder until NJDOT diamond grinded the whole section of roadway in an effort to make it quieter.

[ShawnP]

I like the concrete here in Indiana. One of the local towns has a stretch of 50 year old concrete that's not in that bad of shape. In fact with some work could be repaired to last 30 plus more years.

[seicer]

There were a few issues with trucks hitting overpasses after reasphalting projects on interstates in Indiana. My uncle - a former truck driver, hit an overpass after a resurfacing project that added apparently quite a few inches to the existing pavement, and the height guides and signs had not been updated. The concrete helps maintain height - no need to check after each resurfacing.

As for the concrete pavement at the bridges - it's typically longer than just the approaches. Here is an aerial along I-74: http://goo.gl/maps/Cb3D2. The concrete extends further past the typical approach, and includes an asphalt cushion. Some others on I-74 and I-70 were in a serious state of disrepair - I know one along I-74 was just reasphalted and the other was repaired but is still in awful condition. Not sure on the need for these.

[Interstatefan78]

Here in New Jersey grooved concrete pavement is only found on I-287 from exit 47-66 and driving this stretch has a different whine on your car

It used to be MUCH louder until NJDOT diamond grinded the whole section of roadway in an effort to make it quieter.

You are right about I-287 from exit 47 to 66, but I-78 from exit 52-58 and exit 3 to PA state line  has it concrete pavement being paved with asphalt, but NJDOT needs to look at INDOT and Caltrans for concrete pavement rehab.

[Mamba205]

...sometimes I wish for asphalt when I get tired of the noise from driving over the grooved pavement.

Not to completely dissect your question here, but I wonder if cutting the cement with seemingly random grooves, rather than fixed-width and fixed-spaced grooves, might reduce road noise. There's spans or brides in which the noise is particularly grating.

I only suggest this idea because repetitive "road noise" can be cancelled out somewhat by tire tread patterns which also use non-fixed width tread blocks, grooves, and sipes that are of varying sizes (although they appear similar, usually the inner or outer tread blocks on recent tires are not equally sized. (It should be noted this isn't typically not found on "cheaper" tires or heavy-duty truck tires.)

On the other hand, there's not much incentive to use extra time and expense on this, because there's no real financial benefit, post-construction...but just an idea that suddenly popped in my head.

Yes. When the grooves are arranged in a uniform or repetitive pattern, tires will produce a very tonal (musical note) sound as they impact the grooves. This is because the sound pressure is being centered on a narrow-band frequency, rather than broad-band. If the pattern is broken into a random arrangement, the tread will no longer vibrate harmonically, therefore we will not hear a dominant tone.

[US 41]

Even if the initial asphalt is only 2" thick, it has to be repaved pretty often, and they just put a new layer over the top.  A couple of repavings down the road and the height becomes a problem.

In Terre Haute they use black top. They've redone the black top so much that the curbs are hardly noticeable in some areas.

[Mamba205]

Even if the initial asphalt is only 2" thick, it has to be repaved pretty often, and they just put a new layer over the top.  A couple of repavings down the road and the height becomes a problem.

In Terre Haute they use black top. They've redone the black top so much that the curbs are hardly noticeable in some areas.

I always thought they milled the pavement before pouring in new asphalt. For example, they mill down however many inches and replace it with the same height of new asphalt. I don't see why they would skip the milling process, as just pouring new asphalt on top of the existing pavement would make for a big bump as you drive onto and drive off the new pavement. I've personally never seen it done this way.

[JREwing78]

I've commonly seen city street departments and county road commissions overlay existing asphalt without milling it.

[Mamba205]

I've commonly seen city street departments and county road commissions overlay existing asphalt without milling it.

Interesting. I have, however, seen microsurfacing done and it adds very small height to the pavement profile, about 3/8 inch.