Do my eyes deceive me?...concrete color

[zgardner18]

I'm glad that this thread was started because I have been thinking about painting my concrete bridge and tunnel.  I took Acrylic paint white and just a drop of Latte and painted them.  Then with some powder weathering colors tried to match my photos.  Here take a look:

[Great Western Rwy fan]

I work for a concrete Foundation company,And We Pour our Concrete.We use 1 1/8 inch thick Plywood forms,And We use them Hundreds of times over a period of 4 to 5 years,Until they need to be replaced.

Now for the Color of Concrete,It all depends on temperature and curing and materials and chemicals used to produce the concrete.For instance,Does it have chemicals in it to make it cure faster or to slow down the curing.If it cures too fast You better be able to work fast or You will be in real trouble real quick!! Does it have Hot water?Used in cold climates? Plus the color of the sand used in it makes a difference.

Fresh poured concrete is a dark grey or even a light greenish color,especially when poured in cold weather,In hot weather it's light grey to almost white in color when it cures,On really hot day's above 85 degrees or so it turns white within a couple of hours or less and cures faster,I have poured foundation footings and walked on top of them within 3-4 hours after pouring them.Almost all exposed concrete while be a white color after a few years.

We normally set up a house foundation in 3 days,1st day for footing,2nd day to set up and pour the walls,3rd day to strip the forms.We dont need to seal the concrete to make it cure..Believe me it will cure on its own!!  

been doing this work for 8yrs...just my 2 cents. Ron

 

[modelmaker51]

I know 2 guys that have been in the concrete business for 20 years or more and "pour" concrete. It seems to me, both terms are valid, usage may be regional.

[dti406]

Sorry Rick!

Depending on the job shuttering ply (as we call it) for formwork can be re-used up to 5 or 6 times.  Like rolling stock it gets cascaded to less prestigious work.

The steel stuff is great if you have a big budget or a factory site/plant making things like bridge spans. ... I still think that for most work wood is far more adaptable.

Would you count pumped concrete as "placed" or "poured"? [Serious question].

What do you do about getting concrete to cure properly in very cold conditions?  We have "frostproofing" additives but I doubt that they would cope with some of your conditions.  Do they have an effect on the finished appearance?

Back when I worked for the Highway Department, we were not allowed to use the word poured in any of our correspondence, concrete was always placed.

Regarding cold weather concrete curing, pavement is usually not placed in these conditions, but we did form and place concrete in abutments, piers and other structures.  In these the forms would have insulation placed on the outside and we would cover and heat the inside of the form to get the inside up to an acceptable temperature.  We would use heated water in the concrete and keep thermometers inside the forms to make sure the conrete did not freeze before it finally set up. Also, concrete heats up internally while it cures.  Sometimes it would get so hot inside the forms we would have to uncover the forms to let the heat out.

I have a picture of a job site in Alaska where we covered the entire site with a tent so we could place concrete for the foundations and slabs before setting steel.

Pumped concrete was still placed, although most contractors on bridge work preferred conveyers because more concrete could be delivered and placed quickly. As a side note for bridge decks we would add retarder to delay the set of the concrete so it could be finished properly.

As an aside to the retarder, we were placing a slab bridge (17" thick conrete with #11 reinforcing steel for the structure).  While in the middle of the job the concrete supplier went to a retarder that was measured in ounces while the old one was measured in quarts.  Needless to say the difference was not noted and it was some months for the concrete fully set up.

 

Rick 

[Dave-the-Train]

Sorry Rick!

Maybe you haven't seen Irish "construction site operaives" "placing" concrete.  (... oops!)

Depending on the job shuttering ply (as we call it) for formwork can be re-used up to 5 or 6 times.  Like rolling stock it gets cascaded to less prestigious work.

The steel stuff is great if you have a big budget or a factory site/plant making things like bridge spans. ... I still think that for most work wood is far more adaptable.

I'm forgetting that at some (earlier) periods they used lumber not ply... this can leave the impression of the planks (and gaps) in the finished concrete face.

Would you count pumped concrete as "placed" or "poured"? [Serious question].

Then there's "shot" concrete.  This stuff is impressive.

Incidentally, when we first had the pumped stuff we had a few accidents when the man/men at the delivery end weren't really prepared for the pressure that the muck came out at.

We also have a range of strange names for concrete while it is being made and used/placed.  "Muck" is just one of them.  "Compo" is another... which also gets used for martar.  I haven't got a clue why these odd names get used.

What do you do about getting concrete to cure properly in very cold conditions?  We have "frostproofing" additives but I doubt that they would cope with some of your conditions.  Do they have an effect on the finished appearance?

[R. T. POTEET]

Shawnee, you sent me to the dictionary to read about cement and I found that it is a powder of alumina, silica, lime, iron oxide, and magnesia; these ingredients, when blended together, and kiln-burned give cement its grayish property, about a Value 7 or 8 gray I would guess (Value: the ratio of black to white to produce gray - the more white the higher the value so a Value 7 will be about 2 or three parts black to 10 parts white); it seems to me, therefore, that since the color of cement is going to be rather uniform then the color of our concrete is, to a large measure, going to be determined by the color of our sand or gravel. I would begin coloring my tunnel based upon that factor. What I am trying to say here is that there is really no standard color for concrete and you are going to have pick a grayish coloration depending upon the factor of the color of the sand or gravel used in its mix.

Once I had my tunnel uniformly colored I would age the color with a very thinly shaded wash (shade - the addition of black to a hue) of my basic concrete color keeping in mind that this aging is going to be random across the tunnel face. This should be done with a brush. Once I had my tunnel aged to my perfection I would then weather it. Weathering is not nearly as random as a lot of people might believe; your tunnel portal is going to pretty well accumulate dirt and mud from its surrounding topography; if it is set against a reddish hillside/cliffside then it is going to accumulate dirt and grime of that color; if it is set against a whiteish  hillside/cliffside then it will accumulate a hue of dirt and grime of that color.

I do not see an awful lot of tunnels out here where I live - the Southwest; contrary to what one might assume tunnels are relatively rare in the Rockies. My modeling interest, however, is Appalachian coal haulers and I will need a few on my mainline across the crest of the Appalachians between the Shenandoah and Ohio valleys. I want to make sure that my tunnel portals meet the coloring criteria I have out lined above.

As an aside, as was true almost everywhere engineers out here tried to follow the course of rivers for their mainline. I seem to recall reading somewhere that there were only four tunnels on the whole Denver and Rio Grande system. Unlike we model engineers the prototype engineers did not look at a mountain and say, "Oh! what a beautiful place for a tunnel!" but instead would ask "Is there a practical way to go around this mountain?" The Denver and Salt Lake's operational nightmare of Rollins Pass was not eliminated until the City of Denver bored Moffat Tunnel under the Continental Divide in the 1920s; David Moffat had simply not had the funds to bore a tunnel when he put his railroad into the mountains in the early 1900s. 

[Dave-the-Train]

Concrete:

No 1 - Concrete is never poured, it is placed.

Rick

 

Oops!  I forgot!

Must go and place a pint in my beer glass.

 

[dti406]

Concrete:

No 1 - Concrete is never poured, it is placed.

To answer a few other items brought up.  Form oil is used on the forms in order for the forms to release properly.  At one time wood was used as the forming tool, now steel forms are used as they are reusable and can be modified to most any dimension.

Depending on the location different types of stone is used in the composition of the concrete. In the east limestone is used which leads to the whiter (grayer) color.  In the west a browish gravel is used which leads to the light brown color.

After concrete is placed it is then cured using curing compound which is sprayed over the conrete leading to the white color seen right after the placing process is done.  On bridges the deck is cured using a special clear curing compound.  In older times they water cured the deck for a week and then the deck was sealed with a mixture of mineral spirits and linseed oil which prevented water (salt) penetration. This left the deck with a brownish coloring.  In some locations the gov't agencies would renew this process every few years, this lead to deck lasting a long time prior to replacement.

Just my .02

 

Rick 

 

 

 

[Heartland Division CB&Q]

I've used several methods to simulate concrete pavement. Here's one you may want to experiment with.

I made a flat surface for the road. I mixed two colors using cheap, watered down latex paint. First, I painted with white or very light yellowish sand color. I waited until it completely dried. Next, I apply a gray color close to what is the look of new concrete. Once more, I waited until it was completely dry. Then, I used a stiff, small wire brush and brushed partly through the top color. The brush strokes were always in the same direction as is the case with real concrete pavement. Also, the strokes should not be uniform depth to get color variations as I wanted them. After that, I weathered appropriately with acrylic paints to simulate oil stains and so on. Finally I used a cheap, black ball point pen to make joint lines and cracks.

 

[steamage]

I needed to make the concrete lined wash along the edge of the layout by painting the Masonite. So took a chunk of real concrete to the paint store to match the color and got a quart of flat latex paint mixed. Also drew pencil lines for the concrete joints and weathered with a brown latex wash. Also use the concrete color for painting clouds on the backdrop.

[howmus]

For a start even new concrete is very rarely totally uniform in colour.  Then there's all those interesting things going on...

Aha, Dave hit it right on the head!  The problem with all paints that are called concrete is that concrete isn't a color, but rather a whole lot of colors.  The only way I have found to get anything to really look like concrete is to use a base color (any of the concrete colors) and then drybrush several other "concrete" colors on top.  The same is true of grass a mix of several shades of green foam looks far more realistic than a single color. This isn't the best photo to show it (but is the best I have right now).  The sidewalk in front of the stores was done with 2 different colors of gray spray paint the second sprayed lightly at a distance of 18" or so.  Then I dry brushed another concrete color (WS I think) in places.

 

[topcopdoc]

Concrete Color

Concrete has various colors in nature. After much experimenting to get the right concrete color I settled on these two for all my concrete. Delta Ceramcoat Sanstone diluted to your taste with White Ceramcoat for walls and bridges where the elements have had time to work on it.

I use Delta Ceramcoat Mudstone for station platforms, inspection pits, and turntables etc. where oil and dirt have built up over the years. You can dilute with white paint.

A wash on top of these base coats using India Ink or diluted (browns, blacks or grays) paints or caulk should give you the results you want but you have to experiment. The object is to settle on the base coat first and then apply the aging.

Doc

 

[C&O Fan]

Here's a photo of my highway

the upper portion is painted with Polly Scale aged concrete

The lower is painted with Polly Scale concrete

Neither color is any where close to the real thing !

 

[jeffrey-wimberly]

New concrete is a grayish-white in color. As it ages it gets darker. I've seen concrete in colors ranging from gray-white to almost black.

[Greg H.]

Fresh poured concrete is a med to dark grey, as the water darkens it.   As it dries, it appears white due to excess lime collecting on top durring the drying process.

Once concrete ages, and the excess lime wears away it is a light grey due the minerals in it.  

Compare normal concrete, to the special stuff, they make with very high quality lime ( with no impurities ), and it stays white ( like fresh plaster ), unless it is dirty.

[ndbprr]

The reason it varies is that the surface is porous.  That means that any dirt,dust,oil, etc, that falls on it is going to get in the pores and color it as it ages.  I was surprised when I water blasted my front walk how white it still was after fifty years.  Local condidtions will affect the color.

[Dave-the-Train]

1. Do my eyes deceive me?

If your eyes don't colour probably will.

Simple example:- I have two Athearn GP38-2s.  One is CNW the other is EJ&E.  Physically the models are identical in size.  Sat next to each other (whichever way round)  the "Big J" ALWAYS looks much larger.  This is simply a product of the combination of light, the pigments of orange on the loco (and of yellow and green) and what my brain does with the information received via the optic nerves behind my eyes.

This doesn't even take into account anything like colour blindness and myopia... or an astigmatism...

We only see where we have "light".  How the light is moving, its source and what it may be moving through also go into the equation.

2....concrete color

What cement has been used?

What colour sand has been used?

What colour (and character) aggregate has been used?

What was the mix ratio?

What additives have been put in... possibly including colours.

How was the concrte placed?  (lets assume that it was poured).

What was the shuttering material?  (lets assume that it was 8x4 shuttering ply)

Which way round was the grain of the ply?

Was a release oil, gel or nothing used?

Was the concrete left bare or faces with a screed?

If screeded go back to all the contents list... then ask whether it was floated with wood or steel... one brings out the sand (and sand colour) the other brings out the cement [' can never recall which is which].

Was a "glazed", smooth, "porous" or rough finish created to the cement surface.

Porous and rough surfaces take in and hold much more atmospheric crud more quickly... and stuff like moss can get a hold more easily.

What "stuff" is likely to be landing on the concrete from the environment?  What colour(s) will it be?

What water is landing on the concrete... from what direction (lower walls may get a predominance of water - and content - splashing upwards) and what is it then doing - falling, flowing, standing - ???

Birds?

Trees... among other things creating shadows... or not... influences the effects of sun weathering... among other things...

Ivy... can show on the concrete colouring after it has been ripped off by maintenance men.

Exhaust fumes and blast...

Um... what was the question?

... which "commercial" concrete colour is right?  none of them!

For a start even new concrete is very rarely totally uniform in colour.  Then there's all those interesting things going on...

[Don Gibson]

FRESHYLY POURED concrete is GREY.

It turns WHITE as is it drys.

AGED concrete turns CREAMY YELLOW.

I find Floquil's 'MUD' (diluted) about right.

[loathar]

I did that portal above with the Woodland Scenics earthtone stains. I really like them. Just pour some plaster blocks and practice on them.

[shawnee]

Thanks for the advice of the plaster portals.  My previous ones were Chooch, pre-done.  I'm using AIM plaster ones now.  I'll take a shot at the staining method.

The old concrete color is a bit more toward the yellow.  I'll try cutting it with some sand or buff color folr the stain too.  Hoping someone has a good "recipe" for pollyscale or modelflex or so...i'm using acrylics.

[loathar]

Every company has their own idea of the color should be. New concrete is more grey. Old concrete is more yellow. Polly Scale sells new and aged concrete. A good aged color I found was that cheap craft paint in sandstone color.
If your portals are plaster, I found it looks better if  you brush paint them. Keep dipping your brush in water to make the paint more of a stain. It soaks into the plaster and gives a nice uneven color. Add a couple accent colors while your doing this.

 

[GAPPLEG]

I will almost agree with you on your perception. Fresh new concrete in my eyes is almost white. Older concrete takes on whatever enviroment it's in. My take is use the concrete paint as a base , but get into weathering it with whatever stains you see fit to use to make it work within the scene your working on. Be it rust stains , oil .etc.

[shawnee]

I'm taking a look at airbrushing my tunnel portals, all are concrete...and looking at actual concrete i see, old and new, and the colors offered by Badger and Polly Scale...there's a huge difference.  The concrete is see is more like a deep buff or dirty sand, and the ones they offer all seem grey.  I actually never see grey concrete in the world.  Is it me or my eyes?

Seeing as how realistic colorwhat do you do or mix for realistic concrete color?