New concrete driveway extension questions.


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Old 08-07-08, 11:08 AM
T
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New concrete driveway extension questions.

Well I had a section 5.5x45 (4" thick) poured a week ago. The concrete was finished about 1pm, they told me to wet it down that evening and wash it down a few times the following day.

So on day (3) I walk on it and I am lightly misting it and I notice in a few places there is a little dirt and a little stem of a leaf on the surface and it left a little void in the surface after the dirt washed away The largest is the size of a nickel and about 1/32"-1/16" deep. Am I being too picky about surface inperfections like this? I do see them on just about every slab I look at.

The other question is on day 2 I put some 2foot tall 2x4 pine board on top of a piece of 2x12 to make a stand so I could put string between them so people would not drive on the cement. One of these stands was on the corner of the new cement and now I can see a faint outline of the wood I hope that fades away, you would think the installer would have said something since he saw it sitting there??


My conctrator told me not to drive or park my Ford Explorer on it for (3) days but I am reading here I need to wait 28 days?

Oh when do I put something like thompsons sealer on this?

Thanks!!
 
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Old 08-07-08, 01:53 PM
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Yes. you're being too picky. Just kidding,... sort of.
Sometimes a leaf will blow into a concrete pour, get finished over, and not be seen until it chips out in the manner you described. It's no one's fault unless the finisher saw it and intentionally left it in. Don't know how you'd prove that one. At any rate, your concrete is not going to be perfect forever anyway, so a little flaw at the onset should keep you from worrying too much about the next one you find.
As to the ghosted board image. The concrete cured slower under the board (retained more moisture) and so the concrete is darker there. It will probably bleach out at some point, although there's really no saying how long it might take. The same thing happens if anything is laid atop a new slab before it has fully bleached out.
You can drive on the concrete after one week. The concrete should have gained at least 75% of it's final strength after that time. So if they poured 4,000 psi concrete, it should be a minimum of 3,000 psi after 7 days. That's 3,000 pounds PER SQUARE INCH of compressive strength. Each tire probably has about 48 square inches touching the slab, so your vehicle would have to weigh over 576,000 lbs to crush the concrete. If they put a good base under the slab, you should be fine.
As to the sealer, read the label of whatever you're going to put on. Some can be put on as soon as the concrete will not mar, and others should be put on fully cured concrete (over 28 days). Good luck.

Pecos
 
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Old 08-09-08, 12:02 AM
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Thanks,
I think I will wait the full 30 days since I want to seal it before parking on it.
 
 

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