The difference between Asphalt and Concrete.

[vdeane]

Decades of hearing "kadunk kadunk kadunk" as drivers drove across misaligned joints and then trying to mill them down only led to a greater use of asphalt here.

But that sound gives the road character!

[Tonytone]

All these years and we only have two types of road to lay down.  I think our people at Dot need to go back to the writing board.

No, no, paulthemapguy just identified three different types of hydraulic concrete alone.  I've also driven on graded dirt, oil-sealed, gravel, river rock, cobblestone, and brick roads.  Et cetera.
And we haven't even discussed the different kinds of whitetopping yet.

Whitetopping? Please continue.

Click here.

Now that I know what it is, This seems like a good method of laying down pavement. instead of digging the old out and putting new down. (even though the ikd asphalt can be melted and reused as new asphalt, I wonder if thats where the different color asphalt comes in from pavement markings.)

[formulanone]

Ah, the repetitive noise of concrete, the joints that sometimes cause a steering wheel to jolt out of your hand, the pull it creates while trying to navigate a straight line, the fact it seems to be repaired so shoddily...wait, where was I going with this?

[TheArkansasRoadgeek]

Out East towards Little Rock AHTD uses concrete for a large section of I-40 and it hasn't seen much need for repairing in the maybe five + years seens its laying. We use longitudial grooves vs lat., I wonder why states use both to where it makes squares?

[J N Winkler]

A lot of the NVH and durability problems with Portland cement concrete are functions not of the material itself, but rather the following:

*  Lack of dowelling for smooth load transfer across joints (dowelling is a comparatively recent innovation and you can often see where it has been retrofitted by looking for "staples" of fresh concrete across transverse joints)

*  Low subgrade bearing capacity (making no compromises on CBR costs money up front, but saves a lot of trouble down the road)

*  Loose surface profile standards (Kansas' own example of "whisper concrete," a length of expressway K-96 between Wichita and Hutchinson that was built in the late 1990's, relied on a very tight surface profile standard)

*  Poor subgrade sealing that allows water to percolate through joints and cause "mud pumping" (the traditional preventative, which is not cheap, is to apply a thin asphalt layer directly on top of the subgrade; in Kansas sealants have been tried, but on US 50 between Walton and Florence this approach failed, resulting in early slab cracking that had to be fixed with slab replacements, a dowel retrofit, and finally an asphalt overlay)

Some agencies use diamond grinding on concrete to restore a smooth surface profile; in Kansas this has been done on multiple lengths of I-235 in west Wichita.  I personally don't care for this approach since it degrades steering feel.  It results in a high-pitched whine which I can't hear (better than 90% hearing loss in both ears) but can still feel as a vibration through the steering wheel, and tracking is also affected because the tires try to follow the grooves.  I would rather put up with a very restrained clump-clump-clump (taking into account the owning agency's track record of enforcing minimum bearing capacity, sealing, and surface profile during the initial construction) as a gentle reassurance that I will never have to deal with hydroplaning if it rains.  Rutting is a major cause of hydroplaning on aged asphalt pavements and is one reason I am suspicious of asphalt in areas that receive torrential rain.

Bad NVH on very old concrete pavements in places like Washington state, New York, California, etc. is really a symptom of excess durability, like old porcelain enamel button copy signs that can last for well over fifty years but do not come anywhere close to meeting modern expectations of legibility and color fidelity at night.  These pavements are usually cases where the agency designed and built for a 20- or 25-year life with good sealing and subgrade bearing capacity but a loosey-goosey surface profile standard, and then "gets lucky" and is able to double or triple service life but at the cost (to motorists) of having to accept surface roughness that does not comport well with modern expectations of ride quality and steering feel.

[jjakucyk]

Concrete roads are highly durable and more environmentally friendly as compared to asphalt roads.

I question this statement.  While asphalt is more obvious in its direct use of petroleum products, albeit generally the heaviest and least desirable fraction, it takes a significant amount of energy and resultant carbon emissions to make the portland cement that goes into concrete.  Of course then you have to take into consideration a multitude of other factors, such as longevity (+concrete), recyclability (+asphalt), heat island (+concrete), noise (+asphalt), and others.  But it doesn't seem so cut and dried. 

[1995hoo]

Decades of hearing "kadunk kadunk kadunk" as drivers drove across misaligned joints and then trying to mill them down only led to a greater use of asphalt here.

But that sound gives the road character!

Heh. In 2014 we had the following exchange in a thread titled "If you could bring back one traditional highway practice, what would it be?"

I give you credit for consistency!

I'm wondering what you folks prefer about concrete road surfaces. I've generally preferred asphalt because, when maintained correctly, it's usually smoother and quieter, whereas on many concrete roads I find the seams a lot more noticeable to the point where your car makes what I've always thought of as a "clopping noise."

But I love the clopping noise!

[dfwmapper]

Out here in California concrete was used in copious amounts during the big building era of freeway construction.  The concrete generally holds up very well, but it is loud and definitely isn't exactly something that probably been maintained as well as it should have over the decades (see $5.2 billion thread in Pacific Southwest).  Other states like Arizona use rubberized asphalt in major urban areas which seems to be holding up decently out in the drier climates.  Personally I like it because of how quiet and it made things commuting when I lived in the Valley, I was really surprised to see there actually some detractors who didn't like it.  I can't imagine that the surfaces will hold up as well as the concrete in California, but ADOT has the money why not use it for maintenance?

ADOT's rubberized asphalt is generally a thin overlay on top of a standard PCCP road. They get the best of both worlds: a smooth, quiet surface that doesn't get ruts, but also lasts for many decades without needing full-depth reconstruction. The downside is that the upfront cost is higher than either method on its own. ADOT really doesn't have the money to spend, which is why this treatment is generally reserved for the Phoenix and Tucson metro areas, which have sales taxes dedicated to transportation funding.

[silverback1065]

asphalt is highly recyclable.

[Tonytone]

I wonder why lighting on the roadway surfaces haven't been introduced yet, maybe reflective paint is good enough


iPhone

[In_Correct]

That type of Seasick Cement is used between Gainesville and Denton. Some areas of the Cement is Seasick Cement. It is so noticeable that I was concerned that my car was malfunctioning. The road feels slightly uneven, but it does not make that thumping noise that happens in parts of Oklahoma City. Actually Interstate 35 in Cooke County has no obvious noise at all. It sounds similar to a worn out Asphalt road but since it is Cement Slabs it has a pulsing sound. But it is not loud thumping and the fact that I hear no whistle noise could mean that there are no grooves in that cement. It is possible that the grooves wore away and that the road is very old. ... or a new road with many traffic that wore it out quickly. Before I knew that there is such as thing called Seasick Cement, I thought it was an old and / or worn out road that was repaired so much that the entire road had been repaired but not replaced ... and that they did it smooth enough to not cause the thumping sound but it still results in the Seasick feeling. It is also possible that the road is not old at all, but is still worn out quickly because of the billions of vehicles on Interstate 35. Especially the stretch between Gainesville and Denton is so busy that when the frontage road has a red light, the line is so long it takes the entire ramp and cars are waiting in line on the shoulder.

Does Texas like to use Seasick Cement? The road surface seems to be a lower quality cement but the noise the road makes is loud. These roads are in U.S. 75 Denison, Texas and Loop 288 Denton, Texas. The quieter, older, more worn out Seasick Cement roads are U.S. 75 Sherman, Texas; I-35 Gainesville to Denton with Denton County's stretch slightly louder.

I do not know the type of Cement used in Spur 503 and U.S. 82 Sherman, Texas but it looks old.

Other posts I replied to:

I often refer to Asphalt roads as Tarmac roads, as this is what China refers to them as. I previously thought that other nations never use Cement roads until China news article referred to Ashpalt as Tarmac and Concrete as Cement. (Also, in Hong Kong, which drives the opposide side of the road of China, ... Street View reveals Cement bridges. ... This is unusual because other nations do not seem to use Cement road surface for anything, not even bridges. I might be wrong as I do not yet look at the maps often.) Naming Asphalt or Blacktop as Tarmac (or Blacktop) makes sense because when I think of Concrete: I think of Cement, not Ashpalt.

My preference is for Cement road surfaces almost anywhere. But I noticed that they have Tarmac around Bridges. They should probably have Tarmac there. Also, I noticed that when they add a bridge over the highway, they will add Cement to the road surface under the bridge. I disagree and think that they should have Tarmac. The reason why is because I agree with White Topping because it provides a foundation to the Cement roads. But whenever the Cement surface requires a complete replacement, then instead of digging it out, just put a new cement deck on top of the old cement deck. This should make the foundation even stronger but it makes the road taller, which decreases the clearance of the bridge. If the bridge is replaced the same time that the new Cement is added on top of the old Cement, then the height of the bridge could be raised and the clearance would not be lower.

Another feature I would like to see added to Cement Roads (if possible) is to heat them so that they can be de-iced.

And adding red brick to the outside of the shoulders, or even making the shoulders themselves red brick. Red Brick would make the perfect Rumble Strips.

I also like to see Zippers added to Cement Roads. I am not talking about Barrier Transfer Machines. I am talking about those metal things that expand if it gets hot. They are usually on bridges but the roads known as U.S. 69 and U.S. 75 north of Atoka, Oklahoma appear to have something very similar even though these zippers are part of the regular deck on the ground, not just part of a bridge.

I also like reflectors. They are useful at night especially around road work.

I have driven on roads in Missouri where the grooves do not go across the road. It is weird.

[silverback1065]

unrelated to previous posts, but it really annoys me when people think cement and concrete are the same thing.

[Pink Jazz]

ADOT's rubberized asphalt is generally a thin overlay on top of a standard PCCP road. They get the best of both worlds: a smooth, quiet surface that doesn't get ruts, but also lasts for many decades without needing full-depth reconstruction. The downside is that the upfront cost is higher than either method on its own. ADOT really doesn't have the money to spend, which is why this treatment is generally reserved for the Phoenix and Tucson metro areas, which have sales taxes dedicated to transportation funding.

Actually as far as I know not even Tucson has the rubberized asphalt on PCCP overlay construction; this is exclusive to the Phoenix metropolitan area.

[Plutonic Panda]

I like the look of concrete over asphalt.

[cjk374]

Concrete lasts longer than hot mix.

[hbelkins]

"Just spot attention such as joint repair."

In NY, we have found such attention to be problematic.  Any drive across "repaired" concrete proves how difficult it can be to return a concrete surface to a smooth condition.

Decades of hearing "kadunk kadunk kadunk" as drivers drove across misaligned joints and then trying to mill them down only led to a greater use of asphalt here.

Probably the roughest concrete road I've ever driven is I-86 in the western portion of New York. I'm thinking of the area around Jamestown and Salamanca heading eastward.

[Rothman]

"Just spot attention such as joint repair."

In NY, we have found such attention to be problematic.  Any drive across "repaired" concrete proves how difficult it can be to return a concrete surface to a smooth condition.

Decades of hearing "kadunk kadunk kadunk" as drivers drove across misaligned joints and then trying to mill them down only led to a greater use of asphalt here.

Probably the roughest concrete road I've ever driven is I-86 in the western portion of New York. I'm thinking of the area around Jamestown and Salamanca heading eastward.

The big problem there was the bad relationship between the Senecas and the State.  Last I heard, things were being worked out so the work could be done (if it hasn't already).

[In_Correct]

I drove on both road surfaces on a very hot day and the Tarmac, Blacktop, Hot Mix what ever you want to call it ... is too HOT! 

[silverback1065]

there's hot mix asphalt, and cold mix asphalt.  almost never see cma though. 

[vdeane]

NYSDOT uses CMA on many rural two lane roads.  We put a layer of HMA on top.

[Rothman]

NYSDOT uses CMA on many rural two lane roads.  We put a layer of HMA on top.

Still?  I thought NYSDOT was moving away from CMA.

[cjk374]

You can buy CMA in bags at the big home & hardware stores.

[vdeane]

NYSDOT uses CMA on many rural two lane roads.  We put a layer of HMA on top.

Still?  I thought NYSDOT was moving away from CMA.

Last I checked, cold in-place recycling is standard for VPP projects, at least in Region 1.

[Beltway]

Concrete's biggest weakness IMO is its noise....something that there's been a lot of research on in Minnesota and Iowa to find ways to tweak the concrete surface to reduce road noise.  One idea that came out of Minnesota about 2 decades ago was dragging artificial turf across the surface as it's curing.  MnDOT tested this on I-35W through Richfield when it was rebuilt ca. 1999.

Concrete pavement also in most cases is not smooth, even new or almost new (~5 years) pavements often have seams and little bumps that at least provide some annoyance to the ride.  Older pavements often have more serious spalled sections and broken sections, and in many places you can see asphalt surfaces with the concrete joint bumps shadowing thru.

I just took a trip from Richmond to NW Indiana and noticed a lot of these issues in West Virginia, Ohio and Indiana (I-64, US-35, I-75, I-70, I-65, I-80).  I think it is a good sampling of such problems everywhere, including my state.

I am more and more leaning to opposing the use of concrete (and most have steel rebar reinforcement) for new pavements.  It just seems like most of the time they just don't "get it right", that there are roughness and other problems thru the life cycle of the pavement, and in many places pavements are quite noisy, sometimes making all sorts of odd and changing sounds.  The noisiness also impacts homes and businesses in the area.

When it comes time to do a heavy rehab after 20-25 years or so, these projects are very expensive.

The New Jersey Turnpike demonstrates that full depth asphalt pavement is feasible and favorable on the busiest highways in the world, and on very old highways (it opened in 1951).

[tolbs17]

I wonder why the Greenville Southwest Bypass was built with asphalt and not concrete. Probably because of the low AADT? And, look at the I-840 eastern leg in Greensboro. It's all concrete.

Sometimes I see there's a mix of concrete and asphalt shoulders. I generally prefer it to be either asphalt or concrete, not mixed. That's my opinion.

And yes, I bumped this thread cause I had something to add to it.