Replies

1. 
   SamT | Sep 08, 2003 08:30pm | #1

   Keep it damp for at least 3 days before you drive on it. 7 days is better.

   Want to almost garuntee no cracks? Dampen it, then cover it with visquine, tape the laps, put dirt along the edges and wait 14 days. You can put dirt, rocks, or other weights in the middle to help with the wind.

   Samt

   "You will do me the justice to remember that I have always strenuously supported the right of every man to his opinion, however different that opinion may be to mine. He who denies to another this right, makes a slave of himself to his present opinion, because he precludes himself the right of changing it."   Thomas Paine

1. 
   ccampbell | Sep 08, 2003 08:55pm | #2

   I've been hosing it down regularly for several days.  Today is day three.  I guess I was concerned about the difference between the report on our main driveway versus the pad.  I'm nervous to drive on it for the first time.

2. 
   brownbagg | Sep 08, 2003 09:05pm | #3

   hey, what can I say, Samt is right on te money. at three days is will be about 1700psi seven willl be about 2800 . I poured mine last friday, i,m waiting 14 days myself.

2. 
   Piffin | Sep 08, 2003 11:53pm | #4

   Your neighbors had a lot of luck so don't take theri advice. Three days mionimum and that depends on mix, sils underlying, temperatures and moisture. The plastic cover for hydrocuring does increase the strength. I would be staying off for seven days myself but three will probably be OK in warm weather.

   .

   Excellence is its own reward!

3. 
   RW | Sep 09, 2003 01:37am | #5

   My granddad poured a new drive when I was just a little thing. I remember thinking at the time that it was weird that he had a sprinkler going on the driveway. I'm told he kept it moist for two weeks before so much as walking on it. I guess it paid off. Its nearly thirty years later, he's gone, and that drive doesn't have a single crack in it yet. The planets must have been aligned right at the time.

   "The child is grown / The dream is gone / And I have become / Comfortably numb "      lyrics by Roger Waters

1. 
   IMERC | Sep 09, 2003 02:09am | #6

   No Mars retrograde either... 

   Who ever invented work didn't know how to fish....

4. 
   detroitbob | Sep 09, 2003 03:42am | #7

   Concrete usually develops 75% of its compressive strength in 7 days and full strength in 28 days.  If your contractor placed 5 sack mix with a compressive strength of 3000 psi in 28 days, then at seven days, it should be 2,250 psi.  I think 3 days is quick to put the load of an automobile on green concrete and 5 days is pushing it. 

1. 
   pressagny | Sep 09, 2003 04:57am | #8

   Concrete takes more than 28 days to acheive full strength. Concrete that was used by the Romans 2000 years ago is still strenghtening today. My father who was a researcher in a company that produced concrete told me many years ago that concrete cures foever. Just thought I would let you know

1. 
   RussellAssoc | Sep 09, 2003 05:28am | #9

     You are correct, however, most of the practical strength is achieved in 28- 30 days.  Plus those Roman's were driving small foreign vehicles, with very little weight.

1. 
   markls8 | Sep 09, 2003 07:39am | #10

   Concrete will achieve its RATED psi in about 28 days under recommended curing conditions. It's an arbitrary timeline chosen by engineers in the industry as a consistent point in time to measure the hardness. Concrete will continue to cure ad infinitum only as long as MOISTURE is present. Remove moisture and the curing (hydration) stops. Add moisture again and the curing continues.  However if concrete is frozen too early in the cure then NO amount of time or moisture will ever make it harden.

   - Brian.