What is with the green paint on bridge walls

[roadman65]

I noticed that some bridges ( particularly in the northeast) have the walls under the bridges painted green on the bottom like in the above picture.  Is there a particular reason for this?

[Dirt Roads]

Indeed, there is a reason why many highway agencies painted their steel bridge elements the color green.  Historically, paint colors were derived from colored rocks which were crushed and added to an oil-based substrate.  Most green-colored rocks have an abundance of (you guessed it!) ...copper, which also has both antibiotic and non-corrosive properties.

I've always wondered if the same rationale applied to the selection of green for our beloved BGS signs.

[bing101]

Heres one where US-50 @ I-5 Interchange is located in Sacramento theres a Green paint on the steel beams. 

Same with I-80 in Vallejo has something like that all to delay the rust on steel. 

[Scott5114]

The original question seems to be about green paint on the bridge abutments, not the girders.

[Bitmapped]

I noticed that some bridges ( particularly in the northeast) have the walls under the bridges painted green on the bottom like in the above picture.  Is there a particular reason for this?

My guess would be to try to protect the concrete in the salt spray splash zone.

[pderocco]

I noticed that some bridges ( particularly in the northeast) have the walls under the bridges painted green on the bottom like in the above picture.  Is there a particular reason for this?

My guess would be to try to protect the concrete in the salt spray splash zone.

I don't think concrete needs protection against salt spray.

[Rothman]

I noticed that some bridges ( particularly in the northeast) have the walls under the bridges painted green on the bottom like in the above picture.  Is there a particular reason for this?

My guess would be to try to protect the concrete in the salt spray splash zone.

I don't think concrete needs protection against salt spray.

Why not?  Some salt treatments can certainly corrode concrete.

[pderocco]

I noticed that some bridges ( particularly in the northeast) have the walls under the bridges painted green on the bottom like in the above picture.  Is there a particular reason for this?

My guess would be to try to protect the concrete in the salt spray splash zone.

I don't think concrete needs protection against salt spray.

Why not?  Some salt treatments can certainly corrode concrete.

Then why don't they paint concrete roads green?

[Rothman]

I noticed that some bridges ( particularly in the northeast) have the walls under the bridges painted green on the bottom like in the above picture.  Is there a particular reason for this?

My guess would be to try to protect the concrete in the salt spray splash zone.

I don't think concrete needs protection against salt spray.

Why not?  Some salt treatments can certainly corrode concrete.

Then why don't they paint concrete roads green?

Let's not be silly.  We put a little white and yellow paint on them.

[pderocco]

It could be something completely unrelated: reducing the headlight glare that bounces off the underpass wall onto oncoming traffic.

[kphoger]

Then why don't they paint concrete roads green?

Pavement gets replaced more often than the bridges it goes under.

[Bitmapped]

My guess would be to try to protect the concrete in the salt spray splash zone.

I don't think concrete needs protection against salt spray.

You've clearly never seen bridge piers next to roadways in northern states. Look at older bridges that don't have a sealant applied and you're likely to see concrete spalling. See https://www.dot.state.oh.us/Divisions/Planning/SPR/Research/reportsandplans/Reports/Final%20Reports/FINAL%20Fact%20Sheet%20Protecting%20Piers%20135673.pdf for a discussion of the problem and some solutions.

[pderocco]

My guess would be to try to protect the concrete in the salt spray splash zone.

I don't think concrete needs protection against salt spray.

You've clearly never seen bridge piers next to roadways in northern states. Look at older bridges that don't have a sealant applied and you're likely to see concrete spalling. See https://www.dot.state.oh.us/Divisions/Planning/SPR/Research/reportsandplans/Reports/Final%20Reports/FINAL%20Fact%20Sheet%20Protecting%20Piers%20135673.pdf for a discussion of the problem and some solutions.

Okay, so it sounds like it's actually the steel inside the concrete that causes the problems, because the concrete is slightly porous, and the salt reacts with the steel.

Do snowy climes use asphalt more than concrete? I live in SoCal, and we've got lots of concrete highways, and it looks like they last in the neighborhood of 50 years in the absence of salt. I grew up in New England, and I don't remember as much concrete.

[Rothman]

Do snowy climes states that have a real set of four seasons use asphalt more than concrete?

Yes.

[LilianaUwU]

Another roadman thread about something even the most diehard roadgeeks probably don't pay much attention to.

[kphoger]

Another roadman thread about something even the most diehard roadgeeks probably don't pay much attention to.

A lot of us pay attention to weird minutiae of roadgeekdom.

[Revive 755]

Do snowy climes states that have a real set of four seasons use asphalt more than concrete?

Yes.

I would be curious if there is data to back this.  Iowa gets four seasons yet they seem to have a lot of concrete roads.  Or at least roads that start out as concrete and get an asphalt overlay later.

[Rothman]

Do snowy climes states that have a real set of four seasons use asphalt more than concrete?

Yes.

I would be curious if there is data to back this.  Iowa gets four seasons yet they seem to have a lot of concrete roads.  Or at least roads that start out as concrete and get an asphalt overlay later.

All I can say is here in NY, we use a lot more asphalt than concrete to deal with conditions here.  Seems like every time the concrete lobby persuades someone in NY to install concrete, we end up regretting it over the long term (laughs at the Thruway in the Rochester area).

*continues his crusade to see old concrete that should have never been installed in the first place crack and seated*

(Eh, they keep saying new mixes will be better.  I'll be glad to be proven wrong)

(personal opinion emphasized)

[Revive 755]

^ Maybe it is some local condition in New York?  I can think of a lot of major reconstruction projects in Wisconsin, Illinois, and Indiana that have or are using concrete (though some of the completed projects are holding up better than others).  At least based on Google Maps Florida appears to be using more asphalt (corrections welcomed).

[vdeane]

All I can say is here in NY, we use a lot more asphalt than concrete to deal with conditions here.  Seems like every time the concrete lobby persuades someone in NY to install concrete, we end up regretting it over the long term (laughs at the Thruway in the Rochester area).

*continues his crusade to see old concrete that should have never been installed in the first place crack and seated*

(Eh, they keep saying new mixes will be better.  I'll be glad to be proven wrong)

(personal opinion emphasized)

I feel like issues developed on 39-40 way faster than they ever did on 44-45.  Lots of potholes, especially WB from exit 39 to Warners.  And that's after all the work the Thruway did a couple years ago.

44-45 was real fun back when it would still sing like a bridge in Florida (seriously, they had the same sound; you can kinda hear it on the videos roadwaywizwny posted, though he had the radio too loud to truly appreciate it).  Less fun since it got a diamond grind a while back.  Will be positively boring once the construction is done to make the surface asphalt.

[Road Hog]

I wonder also if the paint is an attempt to combat graffiti. Easy to just spray tags over with the same color paint in seconds, rather than use labor to remove them by spraying remover and scrubbing them off.