Concrete pure white when dry. Is there a fix?

[AMCguy]

I did my walkway in front of my house myself. I didn't feel I had a choice. The paving company bumped my job forward by a month. I had two days to get it dug out, formed and placed or it would have had to wait until the paving was completed. I think it would have been a lot harder then.

I don't think I did anything that caused it to be so white I think it was a lousy batch. It was soupy as hell and took all day to firm up enough that I could begin to tool it. The truck got here at 8:00 am and at 4:00 it was still a sloppy mess. I ended up dragging water off the surface with the broom but I had no choice. I had to be at an important dinner event in an hour.

Anyway, it looks a pleasing shade of, well, concrete when its wet, but when it's dry it turns white as a ghost. I don't like it. If I wet my finger and touch the surface it turns the colour I like for a little while, but then goes back to white. Is there something that will keep it wet looking. I'm afraid if I use sealer it might seal in the problem and keep it from getting wet.

Here's what it looks like for a while after it rains and a close up of what it looks like when it starts to dry.

Thanks, Glenn

 

[Crossfire05]

I did my walkway in front of my house myself. I didn't feel I had a choice. The paving company bumped my job forward by a month. I had two days to get it dug out, formed and placed or it would have had to wait until the paving was completed. I think it would have been a lot harder then.

I don't think I did anything that caused it to be so white I think it was a lousy batch. It was soupy as hell and took all day to firm up enough that I could begin to tool it. The truck got here at 8:00 am and at 4:00 it was still a sloppy mess. I ended up dragging water off the surface with the broom but I had no choice. I had to be at an important dinner event in an hour.

Anyway, it looks a pleasing shade of, well, concrete when its wet, but when it's dry it turns white as a ghost. I don't like it. If I wet my finger and touch the surface it turns the colour I like for a little while, but then goes back to white. Is there something that will keep it wet looking. I'm afraid if I use sealer it might seal in the problem and keep it from getting wet.

Here's what it looks like for a while after it rains and a close up of what it looks like when it starts to dry.

Thanks, Glenn

Sounds like you had a high slump load of concrete. Excessive water will lower the strength and sometimes lead to dusting or deterioration of the surface since there was excessive moisture on the top. If it was a garage slab I would recommend epoxy after it cures to seal the surface (the lower compressive strength does not matter much for a slab on grade). Being a sidewalk there is not a whole lot you can do but wait and watch.

 

[wssix99]

Every cement is a different color, depending on where the limestone and gypsum is mined. The trace elements inside dictate the shade: http://www.cement.org/for-concrete-...tectural-and-decorative-concrete/white-cement

... usually you have to pay more for the whiter stuff...

Color variation in the greys/whites is normal. If you like the wet look, you might be able to find a sealer that will create that lasting effect for you.

 

[rsanter]

Stain it.....

 

[Chris705]

A surface sealer (not a penetrating sealer) typically provides that wet look you are after. Problem is it needs to be applied every year or two depending on the usage.

 

[ConCretin]

What you are seeing is a form of efflorescence, which occurs when salts present in the cement are brought to the surface. In your case, the cause appears to be an excessively wet mix. It will probably diminish with time and there are products to remove it but I doubt either will give you the uniform gray color you want. You could try power washing to remove the salts or experiment with sealers to darken up the color and provide a measure of protection for the surface.

Not to add insult to injury, but that wet mix will probably result in a less durable surface especially if you are in an area the experiences freeze/thaw conditions. For future reference, send the truck back and wait for a another one. A wet load is the fault of the supplier and no reputable firm would have an issue with that. Good luck!

 

[willymakeit]

Extremely wet. What was the fly ash content?

 

[wssix99]

What you are seeing is a form of efflorescence, which occurs when salts present in the cement are brought to the surface.

Would an acid wash to a small area confirm this? (ie: would that clear up an area for a time instead of temporarily hiding it like wetting the slab does?)

 

[PugetDude]

Stain it.....

+1.

 

[nes999]

What did you order from the plant?

Sent from my VS988 using Tapatalk

 

[Stellaontap]

Hi AMCguy

When did you get this done....and how old was the concrete when the picture was taken. It does look like efflorescence to me from your picture. Muriatic acid (1 part acid to 20 parts water) will remove efflorescence. Mix it in a 20L bucket and use a car wash brush to wash the concrete and rinse it right away with water. This should remove the efflorescence. If you just had this concrete placed recently I would wait to wash it with muriatic acid until spring.

Eric

 

[padroo]

My wife wanted a white garage floor and it isn't. She still talks about the white garage floor she wanted and didn't get.

 

[wssix99]

My wife wanted a white garage floor and it isn't. She still talks about the white garage floor she wanted and didn't get.

I would think you'd want to do something like that in epoxy, anyway. A true white concrete won't stay that way for long in a garage - but the epoxy will clean right up.

 

[Crossfire05]

Hi AMCguy

When did you get this done....and how old was the concrete when the picture was taken. It does look like efflorescence to me from your picture. Muriatic acid (1 part acid to 20 parts water) will remove efflorescence. Mix it in a 20L bucket and use a car wash brush to wash the concrete and rinse it right away with water. This should remove the efflorescence. If you just had this concrete placed recently I would wait to wash it with muriatic acid until spring.

Eric

You don't want to etch it unless you are coating it. If the concrete is dusting (symptom of too much water or over finishing) you will know it. Color varies depending of the type of cement used. You can't say that lighter concrete is worse than darker concrete. Efflorescence is a concern in masonry.

 

[bczygan]

Looks good to me.

Were you trying to match something else.

Ultimate fix is R&R.

Bill