Asphalt vs Concrete Freeways

[Big John]

Does anyone know why ISTHA repaved I-94 from Lake-Cook Rd to Half Day Rd in asphalt a couple years back when the rest of the Tri-State from O'Hare north is concrete?

Was it supposed to act as a test control sample to see if they want to use asphalt going forward?

That section may have different soil conditions more conductive to asphalt.

[Road Hog]

When I was a kid I skateboarded in the city park and the "clip clop" of the wheels on the concrete reminded me of riding on the interstate. That's all I got today.

[tolbs17]

https://www.google.com/maps/@36.1256568,-80.1291349,3a,44y,353.47h,89.68t/data=!3m6!1e1!3m4!1sIwQJWktnWl0KVDUBsEVJEw!2e0!7i16384!8i8192

This highway look nice although there is one thing that I don't like about it which is the markings. Where are the black painted markings? Also btw, this highway (Winston-Salem Northern Beltway) transitions into asphalt past the Reidsville Rd interchange.

I'm only saying this cause I'm kind of blind when looking at white-on-white stuff. However at night time, it's not a problem because you have markers which light up...

[tolbs17]

When I ask, which type of asphalt is better? After 9 years I see, it's all crumbled when it was repaved. It's now due for repaving.

https://www.google.com/maps/@35.8906502,-77.6111437,3a,80.2y,278.56h,51.05t/data=!3m7!1e1!3m5!1sNZXsgqI8Aw8oT2zj2THxfg!2e0!5s20110801T000000!7i13312!8i6656

[midwesternroadguy]

Jointed plain concrete pavement is maddening to drive on after it's aged through many freeze-thaw cycles in places where it snows.  The joints get pushed up, so it's like riding waves on a waverunner until you want to barf....but the waves are pavement.

I got news for you.  Asphalt/blacktop does the same thing.  In Minnesota, MNDOT refers to it as tenting.  Certain sandy clay soils create drainage issues that cause tenting.  It's very annoying. 

[Rothman]

Jointed plain concrete pavement is maddening to drive on after it's aged through many freeze-thaw cycles in places where it snows.  The joints get pushed up, so it's like riding waves on a waverunner until you want to barf....but the waves are pavement.

I got news for you.  Asphalt/blacktop does the same thing.  In Minnesota, MNDOT refers to it as tenting.  Certain sandy clay soils create drainage issues that cause tenting.  It's very annoying.

Not every 50 feet or so like concrete.

Also, some DOTs just paved asphalt over concrete rather than being able to afford a crack and seat, just delaying the rhythmic kachonks a while.  See I-81 in Cortland and Broome Counties in NY...

[ran4sh]

Is there a reason why a freeway would be paved with asphalt for one direction (e.g. northbound) and concrete for the other (southbound)? See I-85 between Greenville SC and Anderson SC, which has been paved that way for about a couple of decades now.

[ilpt4u]

The one that blows my mind: Concrete cut and patch sections on an otherwise asphalt paved highway. Have been noticing IDOT D8&D9 do more of that the last couple summers

It creates an interesting driving surface

That said, I have not seen it on freeways. 2 lane roads and boulevards in towns

[Tom958]

I prefer asphalt. Even when major rehab is required, it can be milled down rather than having to be ripped out down to the dirt and replaced as is done with concrete. Asphalt is more forgiving of imprecision in initial placement, too.

[wriddle082]

Is there a reason why a freeway would be paved with asphalt for one direction (e.g. northbound) and concrete for the other (southbound)? See I-85 between Greenville SC and Anderson SC, which has been paved that way for about a couple of decades now.

SC is almost known for this nowadays it seems.  A couple of years ago they finished widening a portion of I-77 north of Columbia, then did pavement rehab (with no widening) on an immediately adjacent stretch north of what was widened.  Most of what was widened or rehabbed was original concrete dating to the late-70’s to early 80’s (because most of I-77 south of Charlotte was late to the game, not actually finished until 1991!).  Anyway, during the process of widening, they laid a brand new concrete lane to the inside median, and my assumption was that they would just diamond grind it all down for the final riding surface, after repouring damaged slabs in the original section.  They did all of that, and then placed asphalt over it all for the final riding surface!  No breaking up of the concrete or anything!  I suppose the freeze/thaw cycle in Columbia just isn’t severe enough for concrete joints to come through the asphalt (it gets down into the upper teens maybe one night a year, and gets up to just over 100 as the highest temp for a week or two in mid-summer).

But anyway, just north of this seemingly asphalt widened section, they paved over the original concrete southbound lanes, but simply repaired and diamond-ground the northbound lanes.  So from Exits 22 to 27, you have northbound concrete and southbound asphalt.

All in all, I *used* to prefer concrete, mainly because it just wasn’t used as much where I was raised (Tennessee), and I liked the sound of the perpendicular grooves.  But the parallel grooves of diamond-ground roads are terrible when you have newer tires, and I’m sure downright dangerous to motorcycles.  Superpave asphalt is the quietest and most resilient of the asphalts, but is very slippery in the rain.  And it rains A LOT in NC and SC!  Since SC has started exclusively using OGFC asphalt on interstates, it’s made a world of difference in rainy conditions.  Overspray is cut down drastically.  Much different in NC, which I think only recently started trying out OGFC and has Superpave everywhere.  Overspray is absolutely horrible when driving through NC in the rain.  The only big issues with OGFC are noisiness (and not in a good way) and it doesn’t hold up as well.  So in a state with poor maintenance practices like SC that isn’t a good combination, but I think they’re trying to be better.  In general, they just don’t use maintenance “best practices” and really need to look to other states for pointers.  Especially when it comes to bridge approaches.  Some states don’t seem to have a problem in that department, while others can never seem to get it right.

I brought up a lot to process, but most of us will be asleep in a few hours anyway, due to eating too much.  Happy Thanksgiving everyone!

[wanderer2575]

Is there a reason why a freeway would be paved with asphalt for one direction (e.g. northbound) and concrete for the other (southbound)? See I-85 between Greenville SC and Anderson SC, which has been paved that way for about a couple of decades now.

I'm guessing:

(1)  May save some $$.
(2)  Research/testing purposes -- comparing longevity of two different builds in identical soils and with identical traffic statistics.

[Tom958]

I-75 between I-475 and Forsyth in three lanes of concrete southbound and four lanes of asphalt northbound. The four lanes northbound eliminates the operational problem of dropping a lane at the 75-475 confluence. Perhaps three lanes of more-durable concrete is expected to be similar in life expectancy to four lanes of less-durable asphalt. 

[ErmineNotyours]

Testing blacktop asphalt:  Quieter pavement test section (polymer).

[Bitmapped]

Is there a reason why a freeway would be paved with asphalt for one direction (e.g. northbound) and concrete for the other (southbound)? See I-85 between Greenville SC and Anderson SC, which has been paved that way for about a couple of decades now.

I'm guessing:

(1)  May save some $$.
(2)  Research/testing purposes -- comparing longevity of two different builds in identical soils and with identical traffic statistics.

Having one side be asphalt and the other side be concrete was explicitly done for research purposes on the US 30 freeway east of Wooster, OH.

[MikieTimT]

On the newly completed Bella Vista Bypass (I-49), the northbound carriageway that was just completed was done with asphalt between the exits where they had pre-paved the unopened carriageway a couple of years ago when they did the overpasses.  They did asphalt on the completed northbound carriageway due to funding constraints to finish the project.  The southbound carriageway is all concrete with asphalt shoulders.

[bwana39]

The reasoning generally to have disparate surfaces on parallel opposite direction lanes generally is done because they are done or redone at different times. The reasoning at a given time may be the financial situation of the road building agency at the time, the current choice of surfaces by the roadbuilding agency at the different times, or something as simple as the bid is for a spec that either would meet or exceed and the particular contractor of a design build project prefers the other (especially in situations where a period of maintenance is included.)

REDONE is probably the bigger reason. In a lot of cases, they put an asphalt layer over existing concrete to smooth the driving surface.  In Texas, most of the rural driving surfaces are asphalt but on the interstates and major arterials, the base is actually concrete. There is a near constant program to mill the surface down to relatively flat and put a new asphalt driving surface.

[tolbs17]

Here's a map that shows a list of all the concrete highways in North Carolina

https://www.arcgis.com/apps/mapviewer/index.html?layers=da4a1a337c6846a7b97030dc00e7c51c

[jdbx]

In Norther California, there are a number of variations even within the same direction of a freeway, usually the result of widening projects using a different material than what was used when the highway was originally constructed.

The most interesting one around here is US-101 between San Jose and Morgan Hill.  This stretch of freeway was built during the early 1980's, and consisted of 2 lanes each way, paved in asphalt.  It became a bottleneck over the years, as US-101 south of Morgan Hill and north of CA-85 was already 3 or 4 lanes in each direction, respectively.  When it was finally widened in the late-90's, 2 lanes were added to the inside shoulder of each direction, a mixed-flow and HOV lane.  These added lanes were constructed of concrete, which gives an interesting effect of the roadway being 50/50 concrete/asphalt:

https://www.google.com/maps/@37.2023968,-121.7112073,3a,75y,139.8h,93.58t/data=!3m7!1e1!3m5!1sGGJo9ENoW7jYxpFlszNM6Q!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DGGJo9ENoW7jYxpFlszNM6Q%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D203.82089%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

Another example, in the opposite direction, is CA-242 in Concord.  It was constructed in the 1960's with the then-typical concrete roadway/asphalt shoulders.  When a third shoulder lane was added in each direction around 2000, it was constructed of asphalt:

https://www.google.com/maps/@37.9755499,-122.0451252,3a,75y,31.4h,90.5t/data=!3m6!1e1!3m4!1sMKDwxAiAGUOysgEI6rMg8Q!2e0!7i16384!8i8192

Its worth noting that those cracked concrete slabs on CA-242 northbound were replaced over this past summer with fresh concrete in a project that resulted in a couple of weekend-long closures of that entire direction of freeway.  Interestingly, the left lane remained paved with asphalt.

I have noticed that most major widening projects in the past few years around here have been paved with the same surface as the existing roadway.  Asphalt freeways widened with asphalt, concrete freeways widened with concrete.

[stevashe]

When I ask, which type of asphalt is better? After 9 years I see, it's all crumbled when it was repaved. It's now due for repaving.

https://www.google.com/maps/@35.8906502,-77.6111437,3a,80.2y,278.56h,51.05t/data=!3m7!1e1!3m5!1sNZXsgqI8Aw8oT2zj2THxfg!2e0!5s20110801T000000!7i13312!8i6656

Actually, this is an interesting case. It looks like the put some sort of chip seal over the asphalt, which is what you see being laid down in that streetview image over top of the normal asphalt of the lane being driven in by the google car. Chip seal is only supposed to last about 5-10 years so the crumbled look it has now is completely ordinary, and the cracks you see are only in that top layer, which could be easily scraped off to reveal the fresh asphalt beneath. I've never seen chip seal used as a sort of sacrificial layer like this before though, only as a fix to prolong the life of asphalt that is starting to wear down, which is what makes this interesting.

You can actually see a little bit of the still fresh-looking asphalt layer below if you look closely at the side of the road: https://goo.gl/maps/iuZpchCvjFns4d1w6

[bwana39]

When I ask, which type of asphalt is better? After 9 years I see, it's all crumbled when it was repaved. It's now due for repaving.

https://www.google.com/maps/@35.8906502,-77.6111437,3a,80.2y,278.56h,51.05t/data=!3m7!1e1!3m5!1sNZXsgqI8Aw8oT2zj2THxfg!2e0!5s20110801T000000!7i13312!8i6656

Actually, this is an interesting case. It looks like the put some sort of chip seal over the asphalt, which is what you see being laid down in that streetview image over top of the normal asphalt of the lane being driven in by the google car. Chip seal is only supposed to last about 5-10 years so the crumbled look it has now is completely ordinary, and the cracks you see are only in that top layer, which could be easily scraped off to reveal the fresh asphalt beneath. I've never seen chip seal used as a sort of sacrificial layer like this before though, only as a fix to prolong the life of asphalt that is starting to wear down, which is what makes this interesting.

You can actually see a little bit of the still fresh-looking asphalt layer below if you look closely at the side of the road: https://goo.gl/maps/iuZpchCvjFns4d1w6

This is the process Texas uses all over the state. The aggregate in the Streetview looks to be more coarse, but this is not the spray and drop chipseal either. This just putting down a layer of hotmix. As to the hotmix resurfacing, in Texas it tends to be replaced from as little as three years to as much as seven or eight. As people who drive on I-20 between Dallas and Louisiana too well know, it seems to be a never ending process that has most stretches undergo milling and resurfacing every three or so years.

My idea of chipseal is where liquid asphalt is sprayed on the road and rock chips or gravel are dropped onto it and it sticks.

[tolbs17]

When I ask, which type of asphalt is better? After 9 years I see, it's all crumbled when it was repaved. It's now due for repaving.

https://www.google.com/maps/@35.8906502,-77.6111437,3a,80.2y,278.56h,51.05t/data=!3m7!1e1!3m5!1sNZXsgqI8Aw8oT2zj2THxfg!2e0!5s20110801T000000!7i13312!8i6656

Actually, this is an interesting case. It looks like the put some sort of chip seal over the asphalt, which is what you see being laid down in that streetview image over top of the normal asphalt of the lane being driven in by the google car. Chip seal is only supposed to last about 5-10 years so the crumbled look it has now is completely ordinary, and the cracks you see are only in that top layer, which could be easily scraped off to reveal the fresh asphalt beneath. I've never seen chip seal used as a sort of sacrificial layer like this before though, only as a fix to prolong the life of asphalt that is starting to wear down, which is what makes this interesting.

You can actually see a little bit of the still fresh-looking asphalt layer below if you look closely at the side of the road: https://goo.gl/maps/iuZpchCvjFns4d1w6

That's great to know. When US-264 was upgraded to interstate standards, they did the same thing so I expect it to crumble in 5-10 years. The normal asphalt can still be seen on the shoulders.

https://www.google.com/maps/@35.608748,-77.4589528,3a,50.3y,298.87h,67.86t/data=!3m6!1e1!3m4!1sngXkAtIcuqzMsIlZqtkOWQ!2e0!7i16384!8i8192

[Bitmapped]

When I ask, which type of asphalt is better? After 9 years I see, it's all crumbled when it was repaved. It's now due for repaving.

https://www.google.com/maps/@35.8906502,-77.6111437,3a,80.2y,278.56h,51.05t/data=!3m7!1e1!3m5!1sNZXsgqI8Aw8oT2zj2THxfg!2e0!5s20110801T000000!7i13312!8i6656

Actually, this is an interesting case. It looks like the put some sort of chip seal over the asphalt, which is what you see being laid down in that streetview image over top of the normal asphalt of the lane being driven in by the google car. Chip seal is only supposed to last about 5-10 years so the crumbled look it has now is completely ordinary, and the cracks you see are only in that top layer, which could be easily scraped off to reveal the fresh asphalt beneath. I've never seen chip seal used as a sort of sacrificial layer like this before though, only as a fix to prolong the life of asphalt that is starting to wear down, which is what makes this interesting.

You can actually see a little bit of the still fresh-looking asphalt layer below if you look closely at the side of the road: https://goo.gl/maps/iuZpchCvjFns4d1w6

That's great to know. When US-264 was upgraded to interstate standards, they did the same thing so I expect it to crumble in 5-10 years. The normal asphalt can still be seen on the shoulders.

https://www.google.com/maps/@35.608748,-77.4589528,3a,50.3y,298.87h,67.86t/data=!3m6!1e1!3m4!1sngXkAtIcuqzMsIlZqtkOWQ!2e0!7i16384!8i8192

That appears to be open graded asphalt. It helps drain water away from the surface and is good for rainy areas. It's not used in the north where it would perform poorly in freeze/thaw cycles.

[tolbs17]

When I ask, which type of asphalt is better? After 9 years I see, it's all crumbled when it was repaved. It's now due for repaving.

https://www.google.com/maps/@35.8906502,-77.6111437,3a,80.2y,278.56h,51.05t/data=!3m7!1e1!3m5!1sNZXsgqI8Aw8oT2zj2THxfg!2e0!5s20110801T000000!7i13312!8i6656

Actually, this is an interesting case. It looks like the put some sort of chip seal over the asphalt, which is what you see being laid down in that streetview image over top of the normal asphalt of the lane being driven in by the google car. Chip seal is only supposed to last about 5-10 years so the crumbled look it has now is completely ordinary, and the cracks you see are only in that top layer, which could be easily scraped off to reveal the fresh asphalt beneath. I've never seen chip seal used as a sort of sacrificial layer like this before though, only as a fix to prolong the life of asphalt that is starting to wear down, which is what makes this interesting.

You can actually see a little bit of the still fresh-looking asphalt layer below if you look closely at the side of the road: https://goo.gl/maps/iuZpchCvjFns4d1w6

That's great to know. When US-264 was upgraded to interstate standards, they did the same thing so I expect it to crumble in 5-10 years. The normal asphalt can still be seen on the shoulders.

https://www.google.com/maps/@35.608748,-77.4589528,3a,50.3y,298.87h,67.86t/data=!3m6!1e1!3m4!1sngXkAtIcuqzMsIlZqtkOWQ!2e0!7i16384!8i8192

That appears to be open graded asphalt. It helps drain water away from the surface and is good for rainy areas. It's not used in the north where it would perform poorly in freeze/thaw cycles.

Even parts of I-40 in North Carolina going to Wilmington is like that too.

[tolbs17]

When this was resurfaced in 2020 or 2021, I wonder what type of asphalt they used for this. Because it's definitely not as dark as compared to US-264 in Pitt and Greene county lines. Is this just a temporary fix or what? It was listed in the pavement rehabilitation.

https://www.google.com/maps/@35.7026215,-77.9839546,3a,45.7y,295.96h,73.63t/data=!3m7!1e1!3m5!1sqHiech8NP3h7eJMjqE0Jmw!2e0!5s20211101T000000!7i16384!8i8192

[jeffandnicole]

When this was resurfaced in 2020 or 2021, I wonder what type of asphalt they used for this. Because it's definitely not as dark as compared to US-264 in Pitt and Greene county lines. Is this just a temporary fix or what? It was listed in the pavement rehabilitation.

https://www.google.com/maps/@35.7026215,-77.9839546,3a,45.7y,295.96h,73.63t/data=!3m7!1e1!3m5!1sqHiech8NP3h7eJMjqE0Jmw!2e0!5s20211101T000000!7i16384!8i8192

Probably just a different blend of asphalt.  Sometimes if it's something really different, they may discuss it on their website.