The black color of asphalt is a ubiquity in our lives and that may not be such a good thing. Black absorbs the sun's energy more effectively than any other color, so it gets hot. In cities, it can make temperatures as much as 10 degrees hotter, it's called the Urban Heat Island effect. Some places have tried painting their streets white to eliminate the problem, but can't they make the asphalt itself white?
And even better, couldn't they use thermochromic dye that turns white only above a certain temperature?
White asphalt would provide less contrast between the road and the sidewalk.
Quote from: 1 on January 29, 2021, 04:33:03 PM
White asphalt would provide less contrast between the road and the sidewalk.
Easy. Make the sidewalks Pepto-Bismol pink.
Random chemical composition of organic compounds in tar, especially with high concentration of aromatic compounds, is likely to have a lot of electron transitions with mostly random energies - hence grey-black coloring.
Color of filling stone may make material brighter, though.
Quote from: kphoger on January 29, 2021, 04:50:32 PM
Quote from: 1 on January 29, 2021, 04:33:03 PM
White asphalt would provide less contrast between the road and the sidewalk.
Easy. Make the sidewalks Pepto-Bismol pink.
Already got some purple-dark pink colored roads north of Boston (due to a few unique quarries which supply the aggregate). Kind of like the color of grape ginger ale.
Back in the 1980s/1990s there was a stretch of US 41 north of Vincennes Indiana that I thought as a child looked like White asphalt. The asphalt had white rocks in it, and as the asphalt itself began to bleach out (or so it looked to me) over the many years, the road had a white-ish appearance. I've never seen another road like that; but I have seen "red" roads in the South and Southwest that use the iron-rich rocks from that area.
Ironically, when they put down road salt around here in the winter, the roads become almost white, precisely when we want them to be black.
Quote from: 1 on January 29, 2021, 04:33:03 PM
White asphalt would provide less contrast between the road and the sidewalk.
And less contrast with the white lines on the road.
Quote from: GaryV on January 29, 2021, 06:19:07 PM
Quote from: 1 on January 29, 2021, 04:33:03 PM
White asphalt would provide less contrast between the road and the sidewalk.
And less contrast with the white lines on the road.
They would have to start using black lines for that.
Quote from: kernals12 on January 29, 2021, 06:50:44 PM
Quote from: GaryV on January 29, 2021, 06:19:07 PM
Quote from: 1 on January 29, 2021, 04:33:03 PM
White asphalt would provide less contrast between the road and the sidewalk.
And less contrast with the white lines on the road.
They would have to start using black lines for that.
There are already black and white combo marks in use, usually on concrete surface
Quote from: kalvado on January 29, 2021, 07:26:19 PM
Quote from: kernals12 on January 29, 2021, 06:50:44 PM
Quote from: GaryV on January 29, 2021, 06:19:07 PM
Quote from: 1 on January 29, 2021, 04:33:03 PM
White asphalt would provide less contrast between the road and the sidewalk.
And less contrast with the white lines on the road.
They would have to start using black lines for that.
There are already black and white combo marks in use, usually on concrete surface
There we go, so it's not a problem at all.
Quote from: kernals12 on January 29, 2021, 05:17:09 PM
Ironically, when they put down road salt around here in the winter, the roads become almost white, precisely when we want them to be black.
because black ice is better than white ice :biggrin:
Dark green asphalt: street parking
Light green asphalt: bike lane
Yellow asphalt: reversible lane, two-way left turn lane, etc.
Red asphalt: one-way in the direction approaching the intersection; do not enter if leaving the intersection
Orange asphalt: interchange ramp
Fluorescent yellow green asphalt: school zone
White asphalt: if a pedestrian tries to cross anywhere within the white asphalt zone, treat it as a crosswalk
Purple asphalt: toll road or toll ramp
Pink asphalt: breast cancer awareness
QR code asphalt: scan for traffic info
Electronic asphalt: warns of congestion ahead if there is any
Vantablack asphalt: used to hide potholes
Quote from: kphoger on January 29, 2021, 09:29:41 PM
Quote from: kernals12 on January 29, 2021, 05:17:09 PM
Ironically, when they put down road salt around here in the winter, the roads become almost white, precisely when we want them to be black.
because black ice is better than white ice :biggrin:
No, it's because in the winter we want the low albedo of asphalt.
Quote from: 1 on January 29, 2021, 09:40:20 PM
Dark green asphalt: street parking
Light green asphalt: bike lane
Yellow asphalt: reversible lane, two-way left turn lane, etc.
Red asphalt: one-way in the direction approaching the intersection; do not enter if leaving the intersection
Orange asphalt: interchange ramp
Fluorescent yellow green asphalt: school zone
White asphalt: if a pedestrian tries to cross anywhere within the white asphalt zone, treat it as a crosswalk
Purple asphalt: toll road or toll ramp
Pink asphalt: breast cancer awareness
QR code asphalt: scan for traffic info
Electronic asphalt: warns of congestion ahead if there is any
Vantablack asphalt: used to hide potholes
Rainbow asphalt: Gay Pride
Quote from: kphoger on January 29, 2021, 09:29:41 PM
Quote from: kernals12 on January 29, 2021, 05:17:09 PM
Ironically, when they put down road salt around here in the winter, the roads become almost white, precisely when we want them to be black.
because black ice is better than white ice :biggrin:
Both are better than vanilla ice.
(I just realized as I was typing this: ICE operates in areas where ice is almost nonexistent.)
I would hate the glare of the sun/headlights off white asphalt.
Quote from: 1 on January 29, 2021, 09:56:47 PM
(I just realized as I was typing this: ICE operates in areas where ice is almost nonexistent.)
You mean places like Sault Ste Marie and International Falls?
Having pavement that absorbs the sun's heat is a feature rather than a bug for half the country half the year.
Quote from: Mdcastle on January 31, 2021, 02:45:50 PM
Having pavement that absorbs the sun's heat is a feature rather than a bug for half the country half the year.
That's why I suggested thermochromic dye, which changes color above a certain temperature. The Ohio DOT is doing some research into it, they've found it reduces pavement temperatures by 6 degrees celsius on hot days while increasing it by 1 degree on cold days
https://ohiomemory.org/digital/collection/p267401ccp2/id/14750/
Quote from: 1 on January 29, 2021, 09:40:20 PM
Dark green asphalt: street parking
Light green asphalt: bike lane
Yellow asphalt: reversible lane, two-way left turn lane, etc.
Red asphalt: one-way in the direction approaching the intersection; do not enter if leaving the intersection
Orange asphalt: interchange ramp
Fluorescent yellow green asphalt: school zone
White asphalt: if a pedestrian tries to cross anywhere within the white asphalt zone, treat it as a crosswalk
Purple asphalt: toll road or toll ramp
Pink asphalt: breast cancer awareness
QR code asphalt: scan for traffic info
Electronic asphalt: warns of congestion ahead if there is any
Vantablack asphalt: used to hide potholes
Jokes aside, I think red is already reserved for bus lanes.
Quote from: kernals12 on January 29, 2021, 04:31:40 PM
The black color of asphalt is a ubiquity in our lives and that may not be such a good thing. Black absorbs the sun's energy more effectively than any other color, so it gets hot. In cities, it can make temperatures as much as 10 degrees hotter, it's called the Urban Heat Island effect. Some places have tried painting their streets white to eliminate the problem, but can't they make the asphalt itself white?
And even better, couldn't they use thermochromic dye that turns white only above a certain temperature?
Yes they can, and they can make different colours of Cement also. My favourite would be red and brown ... to match the colours of brick. ... Or even better: just use bricks. :sombrero:
To answer even more of your question:
Yes they can make Colour Changing Road Surfaces. ... and as with any "new" technology, it has been around a lot longer than you think. One example is turning the road surface pink by it self when the road surface is frozen with ice.
Yes they have defrosting roads also.
All of this is expensive, so I prefer building the roads first. Perhaps change the surface later.
Quote from: In_Correct on January 31, 2021, 07:05:22 PM
Yes they can, and they can make different colours of Cement also. My favourite would be red and brown ... to match the colours of brick. ... Or even better: just use bricks. :sombrero:
As one of my professors told me...
(loud voice) There are no cement roads. There are no cement sidewalks. There are no cement buildings.
It's concrete, and this is true even in places where it's spelt "colour".
Quote from: In_Correct on January 31, 2021, 07:05:22 PM
Quote from: kernals12 on January 29, 2021, 04:31:40 PM
The black color of asphalt is a ubiquity in our lives and that may not be such a good thing. Black absorbs the sun's energy more effectively than any other color, so it gets hot. In cities, it can make temperatures as much as 10 degrees hotter, it's called the Urban Heat Island effect. Some places have tried painting their streets white to eliminate the problem, but can't they make the asphalt itself white?
And even better, couldn't they use thermochromic dye that turns white only above a certain temperature?
Yes they can, and they can make different colours of Cement also. My favourite would be red and brown ... to match the colours of brick. ... Or even better: just use bricks. :sombrero:
To answer even more of your question:
Yes they can make Colour Changing Road Surfaces. ... and as with any "new" technology, it has been around a lot longer than you think. One example is turning the road surface pink by it self when the road surface is frozen with ice.
Yes they have defrosting roads also.
All of this is expensive, so I prefer building the roads first. Perhaps change the surface later.
Maintaining asphalt that gets soft in the summer and cracks in the winter is also expensive, and I would like to solve that problem so that we'll have money to build even more roads.
Quote from: 1 on January 31, 2021, 07:08:03 PM
Quote from: In_Correct on January 31, 2021, 07:05:22 PM
Yes they can, and they can make different colours of Cement also. My favourite would be red and brown ... to match the colours of brick. ... Or even better: just use bricks. :sombrero:
As one of my professors told me...
(loud voice) There are no cement roads. There are no cement sidewalks. There are no cement buildings.
It's concrete, and this is true even in places where it's spelt "colour".
And don't tell anyone, but asphalt is concrete too.
Also, the family I knew growing up who owned a local concrete company referred to the stuff as "cement"–at least in common conversation. And, it being western Kansas, they of course pronounced it SEE-ment.