# How long before concrete should crack?



## lisanmissy (Jul 15, 2007)

I had my driveway apron, parts of the city sidewalk and my front walk to the house and driveway, which was asphalt, replaced last month.  Only the driveway was apshalt, the others were concrete.  Within 1 week, there were 3 control joints that had cracks forming.  It is about 25 days later and the cracks have gotten slightly larger, they are about the thickness of a dime.  In the driveway, there are 2 control joints, one has a crack and the other doesn't.  I came home from vacation yesterday and today I noticed the driveway has a horizontal crack in it that is not in the control joint.  I checked the driveway after coming home yesterday to see how the cracks in the control joints looked and the crack in the driveway wasn't there.  Temps for the low are in the mid 60's and high's are between 80 - 95.  House is in Ohio.   I have yet to park my 2 vehicles on the driveway.  The driveway is 9' wide about 30' in length between the garage and public sidewalk.  There are 2 control joints in the driveway space about 10' apart, each running horizontally.

Should concrete crack this quick?  I was expecting over the next couple of years to see cracks in the control joints but not withing the first 7 days of the pour and not outside of the joints.

Lisa


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## mudmixer (Jul 15, 2007)

Most shrinkage cracks occur in the first few months. A good control joinr (sawed or formed) should crack within a week or two. The amount of shrinkage depends on the amount of water used in the mix (more water, more shrinkage).

If your cracks following the sawed joint as planned?

The "horizontal" (lengthwise?) crack may have closed slightly if the driveway was warm and expanded.

Did you you wire reinforcement for crack control?


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## lisanmissy (Jul 19, 2007)

Most of the cracks are in the joints except for the horizontal one in the drive.  I am not certain if the company that poured the concrete used wire reinforcement.  I was under the impression that they would have placed rebar every 4 feet and they used reinforced concrete (if there is such a thing) with a PSI of 2500.


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