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National Boards => General Highway Talk => Topic started by: silverback1065 on October 31, 2016, 11:20:39 AM

Title: Different colored Asphalt in States
Post by: silverback1065 on October 31, 2016, 11:20:39 AM
I've been wondering this for a while, so I thought I'd ask you guys.  Why is it that some states have different colored asphalt?  What causes this?  I've noticed that Mississippi's asphalt is sometimes red.  What causes this, the aggregate?  An admixture?
Title: Re: Different colored Asphalt in States
Post by: cl94 on October 31, 2016, 12:47:31 PM
PA asphalt is often red because they use aggregate sourced in-state.

One thing I have noticed is that asphalt in Vermont is often quite light-colored compared to other places. Don't know why.
Title: Re: Different colored Asphalt in States
Post by: SectorZ on November 01, 2016, 01:38:29 PM
Anyone know what causes the random purple-tinged color you see in some of the suburbs north of Boston. Saugus comes to mind as having more than a few colored like that.
Title: Re: Different colored Asphalt in States
Post by: jwolfer on November 01, 2016, 01:57:45 PM
Quote from: SectorZ on November 01, 2016, 01:38:29 PM
Anyone know what causes the random purple-tinged color you see in some of the suburbs north of Boston. Saugus comes to mind as having more than a few colored like that.
They are starting rainbow colored pavement.  Different roads are different colors.  Its all party of the "gay mafia agenda" . California another liberal state is doing the same thing

LGMS428

Title: Re: Different colored Asphalt in States
Post by: 20160805 on November 03, 2016, 06:51:14 AM
Quote from: jwolfer on November 01, 2016, 01:57:45 PM
Quote from: SectorZ on November 01, 2016, 01:38:29 PM
Anyone know what causes the random purple-tinged color you see in some of the suburbs north of Boston. Saugus comes to mind as having more than a few colored like that.
They are starting rainbow colored pavement.  Different roads are different colors.  Its all party of the "gay mafia agenda" . California another liberal state is doing the same thing

LGMS428

Seriously?  :paranoid:

I haven't noticed any unusual asphalt colours in my area, but I have noticed double standards as to what roads are asphalt and which are concrete.  I've seen concrete residential streets, but I've also seen asphalt freeways and expressways.
Title: Re: Different colored Asphalt in States
Post by: jwolfer on November 03, 2016, 07:41:24 AM
Quote from: 20160805 on November 03, 2016, 06:51:14 AM
Quote from: jwolfer on November 01, 2016, 01:57:45 PM
Quote from: SectorZ on November 01, 2016, 01:38:29 PM
Anyone know what causes the random purple-tinged color you see in some of the suburbs north of Boston. Saugus comes to mind as having more than a few colored like that.
They are starting rainbow colored pavement.  Different roads are different colors.  Its all party of the "gay mafia agenda" . California another liberal state is doing the same thing

LGMS428

Seriously?  :paranoid:

I haven't noticed any unusual asphalt colours in my area, but I have noticed double standards as to what roads are asphalt and which are concrete.  I've seen concrete residential streets, but I've also seen asphalt freeways and expressways.
SARCASAM

LGMS428

Title: Re: Different colored Asphalt in States
Post by: Mr. Matté on November 03, 2016, 12:17:04 PM
Quote from: jwolfer on November 03, 2016, 07:41:24 AM
Quote from: 20160805 on November 03, 2016, 06:51:14 AM
Quote from: jwolfer on November 01, 2016, 01:57:45 PM
Quote from: SectorZ on November 01, 2016, 01:38:29 PM
Anyone know what causes the random purple-tinged color you see in some of the suburbs north of Boston. Saugus comes to mind as having more than a few colored like that.
They are starting rainbow colored pavement.  Different roads are different colors.  Its all party of the "gay mafia agenda" . California another liberal state is doing the same thing

LGMS428

Seriously?  :paranoid:

I haven't noticed any unusual asphalt colours in my area, but I have noticed double standards as to what roads are asphalt and which are concrete.  I've seen concrete residential streets, but I've also seen asphalt freeways and expressways.
SARCASAM

LGMS428

Besides, the gay mafia is clearly using thermoplastic:
(https://farm4.staticflickr.com/3708/19595827208_977529e170_b.jpg)
(https://www.aaroads.com/forum/index.php?topic=16157.0)
Title: Re: Different colored Asphalt in States
Post by: jwolfer on November 03, 2016, 01:24:22 PM
Quote from: Mr. Matté on November 03, 2016, 12:17:04 PM
Quote from: jwolfer on November 03, 2016, 07:41:24 AM
Quote from: 20160805 on November 03, 2016, 06:51:14 AM
Quote from: jwolfer on November 01, 2016, 01:57:45 PM
Quote from: SectorZ on November 01, 2016, 01:38:29 PM
Anyone know what causes the random purple-tinged color you see in some of the suburbs north of Boston. Saugus comes to mind as having more than a few colored like that.
They are starting rainbow colored pavement.  Different roads are different colors.  Its all party of the "gay mafia agenda" . California another liberal state is doing the same thing

LGMS428

Seriously?  :paranoid:

I haven't noticed any unusual asphalt colours in my area, but I have noticed double standards as to what roads are asphalt and which are concrete.  I've seen concrete residential streets, but I've also seen asphalt freeways and expressways.
SARCASAM

LGMS428

Besides, the gay mafia is clearly using thermoplastic:
(https://farm4.staticflickr.com/3708/19595827208_977529e170_b.jpg)
(https://www.aaroads.com/forum/index.php?topic=16157.0)
Oh my goodness. That is just fabulous!

LGMS428

Title: Re: Different colored Asphalt in States
Post by: MikeCL on November 06, 2016, 01:23:03 AM
I have a question somewhat like the op but what I've noticed is say when they repave a road it's almost much darker then the original and has less rock and looks like more tar?
Title: Re: Different colored Asphalt in States
Post by: silverback1065 on November 06, 2016, 03:19:02 PM
Quote from: MikeCL on November 06, 2016, 01:23:03 AM
I have a question somewhat like the op but what I've noticed is say when they repave a road it's almost much darker then the original and has less rock and looks like more tar?

when they repave a road, they put in new surface asphalt, and some extra binder.  the extra binder is what makes it so dark.  it will get bleached by the sun over time though and turn more gray.
Title: Re: Different colored Asphalt in States
Post by: MikeCL on November 06, 2016, 10:25:03 PM
Quote from: silverback1065 on November 06, 2016, 03:19:02 PM
Quote from: MikeCL on November 06, 2016, 01:23:03 AM
I have a question somewhat like the op but what I've noticed is say when they repave a road it's almost much darker then the original and has less rock and looks like more tar?

when they repave a road, they put in new surface asphalt, and some extra binder.  the extra binder is what makes it so dark.  it will get bleached by the sun over time though and turn more gray.
My thing is has it always been like this or something new to add extra binder?
Title: Re: Different colored Asphalt in States
Post by: silverback1065 on November 06, 2016, 10:28:49 PM
Quote from: MikeCL on November 06, 2016, 10:25:03 PM
Quote from: silverback1065 on November 06, 2016, 03:19:02 PM
Quote from: MikeCL on November 06, 2016, 01:23:03 AM
I have a question somewhat like the op but what I've noticed is say when they repave a road it's almost much darker then the original and has less rock and looks like more tar?

when they repave a road, they put in new surface asphalt, and some extra binder.  the extra binder is what makes it so dark.  it will get bleached by the sun over time though and turn more gray.
My thing is has it always been like this or something new to add extra binder?

i believe it depends on the project.  but if this is done a lot, you get situations where the road is almost equal in height as the curb, which causes the municipality to have to raise the curb (if they're competent).  i've seen situations where they mill say, 2" off, and replace with 2" of surface and binder, this will cause the new surface to be higher than the old. 
Title: Re: Different colored Asphalt in States
Post by: MikeCL on November 06, 2016, 10:30:44 PM
Quote from: silverback1065 on November 06, 2016, 10:28:49 PM
Quote from: MikeCL on November 06, 2016, 10:25:03 PM
Quote from: silverback1065 on November 06, 2016, 03:19:02 PM
Quote from: MikeCL on November 06, 2016, 01:23:03 AM
I have a question somewhat like the op but what I've noticed is say when they repave a road it's almost much darker then the original and has less rock and looks like more tar?

when they repave a road, they put in new surface asphalt, and some extra binder.  the extra binder is what makes it so dark.  it will get bleached by the sun over time though and turn more gray.
My thing is has it always been like this or something new to add extra binder?

i believe it depends on the project.  but if this is done a lot, you get situations where the road is almost equal in height as the curb, which causes the municipality to have to raise the curb (if they're competent).  i've seen situations where they mill say, 2" off, and replace with 2" of surface and binder, this will cause the new surface to be higher than the old.
I was happy they did the street I live on I'm not sure why but it was as slick as ice when it had any type of water on it with the re-pavement it far better less rocks in it I see
Title: Re: Different colored Asphalt in States
Post by: TEG24601 on November 07, 2016, 10:34:38 AM
It does appear to be greatly influenced by the aggregate or binder.  In Washington, SR-20, through the North Cascades is colored Red, because they used the rock they blasted to build the road, to make the asphalt.
Title: Re: Different colored Asphalt in States
Post by: Rothman on November 07, 2016, 01:02:47 PM
In southeastern Idaho, pavement can get a red color due to their using lava as a snow/ice treatment.
Title: Re: Different colored Asphalt in States
Post by: roadman65 on November 08, 2016, 05:19:33 PM
Better question is why does Florida's asphalt start out black and then turn white after a few years?  I always thought it was the sun bleaching it, but I have seen some paving projects use a different texture asphalt that retain the black colore even after 20 years.

Of course back to the OP, not all states are standard state wide either.  FL is red textured in the Panhandle while the main Peninsula is the black that turns white.
Title: Re: Different colored Asphalt in States
Post by: Revive 755 on November 08, 2016, 10:29:52 PM
Quote from: roadman65 on November 08, 2016, 05:19:33 PM
Better question is why does Florida's asphalt start out black and then turn white after a few years?  I always thought it was the sun bleaching it, but I have seen some paving projects use a different texture asphalt that retain the black colore even after 20 years.

I believe it has something to do with oxidation and the material ratios - particularly with the amount of binder and recycled materials - in the asphalt mix.
Title: Re: Different colored Asphalt in States
Post by: Gnutella on March 10, 2018, 12:09:39 PM
Is it just me, or does Missouri use very large rocks in their asphalt aggregate?
Title: Re: Different colored Asphalt in States
Post by: US71 on March 10, 2018, 01:37:34 PM
Quote from: silverback1065 on October 31, 2016, 11:20:39 AM
I've been wondering this for a while, so I thought I'd ask you guys.  Why is it that some states have different colored asphalt?  What causes this?  I've noticed that Mississippi's asphalt is sometimes red.  What causes this, the aggregate?  An admixture?

I know some of Oklahoma's older roads are reddish looking. Maybe has something to do with the iron content of the gravel used?
Title: Re: Different colored Asphalt in States
Post by: formulanone on March 10, 2018, 07:04:51 PM
Quote from: Revive 755 on November 08, 2016, 10:29:52 PM
Quote from: roadman65 on November 08, 2016, 05:19:33 PM
Better question is why does Florida's asphalt start out black and then turn white after a few years?  I always thought it was the sun bleaching it, but I have seen some paving projects use a different texture asphalt that retain the black colore even after 20 years.

I believe it has something to do with oxidation and the material ratios - particularly with the amount of binder and recycled materials - in the asphalt mix.

There's lots of shell rock, coral, and limestone in most of Florida's pavement. It really bleaches over time like almost nowhere else, but get get a closer look, and the sharp texture reveals the ocean's skeletal bounty.

I suppose it depends on how it fades or how much recycled material is used. A buddy of mine who used to be in the paving industry told me it's very close to 100% nowadays.

Alabama, Mississippi, and southwestern Tennessee seem to have lot of red in their pavement, though it differs from place to place as the oil and layers wear down. Oklahoma and Arkansas also have some reddish pavement.

I've seen some blue, purple, and greenish tints in sporadic locations around the country.
Title: Re: Different colored Asphalt in States
Post by: wriddle082 on March 10, 2018, 07:55:59 PM
In Georgia and the Carolinas, with the high granite content in the aggregate, you can see sparkles in the pavement when the sun hits it just right.
Title: Re: Different colored Asphalt in States
Post by: mrcmc888 on March 12, 2018, 06:46:36 AM
Quote from: wriddle082 on March 10, 2018, 07:55:59 PM
In Georgia and the Carolinas, with the high granite content in the aggregate, you can see sparkles in the pavement when the sun hits it just right.

Tennessee has that as well.  One thing I've noticed with East Tennessee asphalt is that it seemingly never fades.  It takes years for a freshly-paved section of road to bleach into even dark gray.
Title: Re: Different colored Asphalt in States
Post by: adventurernumber1 on March 19, 2018, 10:39:11 AM
Most of the time I see the typical black and grey asphalt, and white and yellow and tan concrete, but fairly often I have seen unusual colors for pavements as well.

The most prominent examples of this are the almost-white-colored asphalt many places in Florida, and the brown and red colored asphalt all over the place in states like Tennessee and Mississippi. My parents told me that each of these respective occurrences were because Florida used sand in their pavement and Tennessee used clay in their pavement, but someone here would have to confirm that information. In TN, for example, it is quite typical for an asphalt road to be resurfaced (or paved for the first time if it is new) looking black, but then by the time a few years passes it may usually be either grey or red/brown (if it is a road that has a brownish color to it, it will usually show up by the time a few years pass). My home state of Georgia almost never has very unusual colors with any of their pavements (at least on main roads), but the most prominent example of an oddity regarding that (that no longer exists) was several years ago when a short section of Georgia Highway 201 in Whitfield County had brownish asphalt not unlike that found prominently in Tennessee, until it was resurfaced in Fall 2014. This coloring was more evident closer to 2014 before it was resurfaced (at the end of its life), but here is 2008 GMSV showcasing this: https://www.google.com/maps/@34.8779177,-84.9829193,3a,75y,271.2h,88.35t/data=!3m6!1e1!3m4!1svBbage_-yCBe-g7nrPqH0w!2e0!7i3328!8i1664

Here is some GMSV showing the reddish-brown asphalt roads often found in the state of Tennessee: https://www.google.com/maps/@35.0595731,-85.1927593,3a,75y,340.21h,85.74t/data=!3m7!1e1!3m5!1sQIj-bY8KNZOHYRXFn-vvnQ!2e0!6s%2F%2Fgeo2.ggpht.com%2Fcbk%3Fpanoid%3DQIj-bY8KNZOHYRXFn-vvnQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D93.59545%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

Here is some GMSV showing the white-ish asphalt roads often found in the state of Florida: https://www.google.com/maps/@29.1291925,-81.125851,3a,75y,35.33h,88.9t/data=!3m6!1e1!3m4!1swH_0ADemz8REI0PxsyeeRQ!2e0!7i13312!8i6656


Title: Re: Different colored Asphalt in States
Post by: Max Rockatansky on March 19, 2018, 11:11:30 AM
A lot of the older roads in the Mojave in San Bernardino County in California have a red tinge to them.  My understanding was that the quarry that the materials was mined from had a lot of iron oxide or could have some sort of sand stone mix.  Kelbaker Road comes to mind has having some really red looking secitons.
Title: Re: Different colored Asphalt in States
Post by: hotdogPi on March 19, 2018, 11:15:00 AM
Reading, MA has red (about this color) asphalt on some of its minor streets.
Title: Re: Different colored Asphalt in States
Post by: roadman65 on March 26, 2018, 08:26:51 PM
Florida differs by region.  The Panhandle has a different color than the Peninsula.  The Peninsula uses a grey type, even though its black when applied.  However, in Orlando since milling the old asphalt, the colors now are much darker after exposed for years to the elements.

Title: Re: Different colored Asphalt in States
Post by: MikeCL on September 16, 2018, 10:09:03 PM
Quote from: mrcmc888 on March 12, 2018, 06:46:36 AM
Quote from: wriddle082 on March 10, 2018, 07:55:59 PM
In Georgia and the Carolinas, with the high granite content in the aggregate, you can see sparkles in the pavement when the sun hits it just right.

Tennessee has that as well.  One thing I've noticed with East Tennessee asphalt is that it seemingly never fades.  It takes years for a freshly-paved section of road to bleach into even dark gray.
I wish roads would stay mostly dark
Title: Re: Different colored Asphalt in States
Post by: Road Hog on September 18, 2018, 11:38:11 AM
Not asphalt, but I remember as a kid that Mississippi chip-sealed its roads extensively with reddish-pink gravel.
Title: Re: Different colored Asphalt in States
Post by: CapeCodder on September 18, 2018, 09:17:16 PM
Quote from: Gnutella on March 10, 2018, 12:09:39 PM
Is it just me, or does Missouri use very large rocks in their asphalt aggregate?

Yes. When those SOB's come loose and hit your windshield...
Title: Re: Different colored Asphalt in States
Post by: sparker on September 19, 2018, 01:01:13 AM
Many of the roads in NE California display a distinctive reddish-brown tint, since the asphalt mix utilizes local clays, which have a high iron content (simply look at the sides of road cuts in the region).  Back in the '80's, much of I-80 from Auburn to Colfax was repaved with a similar asphalt mixture and also displayed that particular tint. 
Title: Re: Different colored Asphalt in States
Post by: Rothman on September 19, 2018, 12:11:46 PM
In southeastern ID, they use red lava as a melt treatment.  Turns everything red and sticks to your wheelwells, but supposedly does not have the corrosive quality of typical salt treatments.
Title: Re: Different colored Asphalt in States
Post by: rarnold on September 19, 2018, 09:40:08 PM
Quote from: roadman65 on November 08, 2016, 05:19:33 PM
Better question is why does Florida's asphalt start out black and then turn white after a few years?  I always thought it was the sun bleaching it, but I have seen some paving projects use a different texture asphalt that retain the black colore even after 20 years.

Of course back to the OP, not all states are standard state wide either.  FL is red textured in the Panhandle while the main Peninsula is the black that turns white.

The difference in color comes from the gravel used. If the rock has more iron in it, you get red asphalt. If the asphalt is more limestone, the black fades away to reveal a whiter-looking asphalt. I figured this out going to North Central Idaho where the gravel is mostly granite from the area, which is a pewter color so it always looks black, but it too even fades over time.

Concrete would do this as well except the portland cement used in the mix and the sand help to keep the color lighter.
Title: Re: Different colored Asphalt in States
Post by: SD Mapman on September 20, 2018, 12:16:07 AM
Quote from: rarnold on September 19, 2018, 09:40:08 PM
The difference in color comes from the gravel used.

To quote an interesting example, they did a resurfacing in the area a couple years ago using two different quarries for the gravel and you could clearly see that the asphalt from one was slightly redder than the asphalt from the other.

In this case the color changed (only slightly) within the same project.
Title: Re: Different colored Asphalt in States
Post by: mrcmc888 on September 21, 2018, 09:50:27 PM
Newcastle County DE and the Lancaster, PA regions' asphalt is limestone gray ranging to white.
Title: Re: Different colored Asphalt in States
Post by: TheOneKEA on September 21, 2018, 11:09:49 PM
Interstate 68 west of Sideling Hill, MD is frequently paved with reddish asphalt. Interstate 70 in Hancock, MD is similarly paved. I always assumed that the asphalt was formulated differently to deal with the snow and ice accumulation in winter.
Title: Re: Different colored Asphalt in States
Post by: oscar on September 21, 2018, 11:31:33 PM
The "Red Road" on Hawaii's Big Island (county route 137) once was surfaced mostly with red cinder asphalt (http://www.hawaiihighways.com/photos-Red-Road.htm), using a bunker oil binder. When most of the road was repaved (after constant complaints about the rough surface aggravating residents' back problems), the new surface was regular black asphalt, since bunker oil was no longer a permissible binder. The northernmost two miles of the road kept its original red surface, though I'm unsure it survived this year's lava flows which covered parts of the Red Road.
Title: Re: Different colored Asphalt in States
Post by: MikieTimT on September 25, 2018, 09:02:34 AM
Arkansas has very different terrain in the northwest half than it is in the southeast half of the state.  Not to mention, almost each county has its own road crew and Arkansas runs most everything at a district level, so there's a substantial difference evident pretty much at each county line a state highway crosses.  It's even the case for many U.S. and Interstate highways.
Title: Re: Different colored Asphalt in States
Post by: ET21 on September 26, 2018, 08:41:31 AM
I noticed on Friday that the re-surfaced part of IL-390 from I-290 westward has this color while the majority of other pavements on the system are the usual black asphalt. Maybe the Tollway is testing this to see if it lasts longer???
Title: Re: Different colored Asphalt in States
Post by: Beltway on September 26, 2018, 09:18:19 AM
https://www.lonestarpavingtx.com/colored-asphalt/

Quotes:

Asphalt surface is typically called blacktop because of the color, but not all asphalt is black in color.  This color of roads is determined by the input materials that consist of bitumen, an asphalt cement, and aggregate rock.  Bitumen is naturally black, but there are some surfaces that use dies and even different colored rock to pave with.

Roads in Arizona are sometimes red in color, this is not because of any dyes that are used, but because of the rock used as aggregate.  Because it is not cost effective to ship stone and crushed rock long distances to be used in paving projects local quarries are often the supplier to local roads.  Bedrock in Arizona is high in copper and iron deposits, which is why the rock is a dark red.

When the red rock is used as a paving material the road will not appear red at first.  The top layer of asphalt cement will still give the road a black color, but over time the top layer will wear away turning the road red.

Title: Re: Different colored Asphalt in States
Post by: jon daly on September 26, 2018, 11:34:42 AM
I'm not sure why, but this is one of my favorite recent threads.
Title: Re: Different colored Asphalt in States
Post by: Tonytone on September 26, 2018, 12:12:58 PM
Quote from: mrcmc888 on September 21, 2018, 09:50:27 PM
Newcastle County DE and the Lancaster, PA regions' asphalt is limestone gray ranging to white.
Ive seen Red asphalt in Pa. especially in that Lancaster area.


iPhone
Title: Re: Different colored Asphalt in States
Post by: index on September 26, 2018, 12:51:52 PM
I have yet to see asphalt other than some shade of grey that isn't light in NC. South Carolina, on the other hand, seems to have the same thing as Florida with its asphalt, a lot of it turns light grey to white after it's paved.
Title: Re: Different colored Asphalt in States
Post by: adventurernumber1 on October 06, 2018, 06:52:34 PM
Quote from: Beltway on September 26, 2018, 09:18:19 AM
https://www.lonestarpavingtx.com/colored-asphalt/

Quotes:

Asphalt surface is typically called blacktop because of the color, but not all asphalt is black in color.  This color of roads is determined by the input materials that consist of bitumen, an asphalt cement, and aggregate rock.  Bitumen is naturally black, but there are some surfaces that use dies and even different colored rock to pave with.

Roads in Arizona are sometimes red in color, this is not because of any dyes that are used, but because of the rock used as aggregate.  Because it is not cost effective to ship stone and crushed rock long distances to be used in paving projects local quarries are often the supplier to local roads.  Bedrock in Arizona is high in copper and iron deposits, which is why the rock is a dark red.

When the red rock is used as a paving material the road will not appear red at first.  The top layer of asphalt cement will still give the road a black color, but over time the top layer will wear away turning the road red.


This makes a lot of sense. In Tennessee you will often find asphalt roads that have a brown or reddish look, but on the roads that look like that, the pavement is usually older. This would explain why whenever a road is newly paved with asphalt in Tennessee, it usually still looks black at first. However, as time goes on, it seems to gravitate more to a brown or red look, which is typical for many asphalt roads in states in my region such as Tennessee, Mississippi, and Arkansas that have these occurrences. My home state of Georgia typically has asphalt roads that look black at first but then some kind of grey later on as they age. Florida's asphalt roads tend to often look more white-ish and light grey as they age - and so does South Carolina, as index notes.
Title: Re: Different colored Asphalt in States
Post by: Beltway on October 06, 2018, 07:20:37 PM
Liquid asphalt (a very heavy distillate of petroleum) is typically black in color.  So a newly paved road would have the asphalt cement mixed thru including on the top.  As the road wears from traffic the asphalt wears away and more of the aggregate is exposed to the surface, and shows the color of the aggregate (whitish, red, etc.).
Title: Re: Different colored Asphalt in States
Post by: qguy on October 07, 2018, 05:22:33 PM
Quote from: Beltway on October 06, 2018, 07:20:37 PM
Liquid asphalt (a very heavy distillate of petroleum) is typically black in color.  So a newly paved road would have the asphalt cement mixed thru including on the top.  As the road wears from traffic the asphalt wears away and more of the aggregate is exposed to the surface, and shows the color of the aggregate (whitish, red, etc.).

Roadsguy (my son) can confirm that this is precisely the explanation I provided him since he first asked me this thread's question seemingly six months after he was born.
Title: Re: Different colored Asphalt in States
Post by: ATLRedSoxFan on October 09, 2018, 04:02:09 AM
I can remember as a kid, when Tennessee was first building their interstates, the off ramps had red tinted as fault and on ramps had green tinted as fault. A couple other states did this too, just can't remember which ones.