Concrete Pad - How long to wait?

[wildtoad]

For those that have had a 6" concrete pad poured for the cars/motorhome how long did you wait before rolling the mh on it? Mine is on a 20k chassis.

Thanks.

[YosemiteBobR]

30 days for mine. But I think the contractor was protecting himself.

[ransil]

I waited 30 days, some said to go earlier but I wanted to be safer. Other junk went in after a week

[what next]

I had several bids on my pad and all the contractors said 2 weeks. I will actually be gone the 3rd week so it gets a little extra time. 37,000 lbs for me.

[vsheetz]

30 days to my thinking. Just to be sure.

[mel s]

Originally Posted by wildtoad

For those that have had a 6" concrete pad poured for the cars/motorhome how long did you wait before rolling the mh on it? Mine is on a 20k chassis.
Thanks.

wildtoad
I waited 30 days.
See: The 28-Day Myth - National Precast Concrete Association and decide for yourself how long to wait.
Mel
'96 Safari

[Skip426]

Concrete , for a full cure , requires 28 days , to get to full strength.
New patio; 4" thick , poured on Thursday; instructions were : OK to walk on after 36 hrs. clean with water hose or broom after 72 hrs, remove forms 3 days, furniture 7 days , but don't slide it around.

EDIT: I see Mel has posted some interesting info while I was typing , I'll say it again " Boy I type slow !"

[joshuajim]

Having broken thousands of cylinders while building a half a Billion dollars worth of schools and public works projects, I can assure you that the 7 day break will be 75 to 80% of design strength and the 28 day break will be 110 to 140% of design. Being public schools, we took 4 cylinders out of the first truck and 4 out of every second truck after that. On a 250 CY pour, that's a lot of cylinders. A 7 day, 2 ea 28 day and a hold.

We were required to have a batch plant inspector that watched the batching. I can't guarantee that your local concrete pre-mix company will hold to the high standards we had.

[Slice]

I was on mine on the 7 th day.. 35,000k no cracks no nothing.

[Lovin2Camp]

Waited 7 days in 2009 to put my 20,000 pound Motorhome on it....
Not a crack in the concrete today!!👍


Sent from my iPhone using iRV2 - RV Forum

[coachmanjay]

A subtle point is being missed here. It is not the total weight that is important but the pressure being exerted on the concrete, which corresponds to your tire pressure. (65psi to 125 psi) Almost any concrete will have a resistance strength of 2000 psi at 7 days,

[Scottybdivin]

Originally Posted by joshuajim

Having broken thousands of cylinders while building a half a Billion dollars worth of schools and public works projects, I can assure you that the 7 day break will be 75 to 80% of design strength and the 28 day break will be 110 to 140% of design. Being public schools, we took 4 cylinders out of the first truck and 4 out of every second truck after that. On a 250 CY pour, that's a lot of cylinders. A 7 day, 2 ea 28 day and a hold.

We were required to have a batch plant inspector that watched the batching. I can't guarantee that your local concrete pre-mix company will hold to the high standards we had.

I agree. We rarely see a 7 day break that doesen't already exceed the 28 day design strength.

[BoDu]

Strength is one important aspect of the concrete. But one of the highest forces exerted on concrete as it hydrates is shrinkage tension. Providing a way to control cracking, generally by sawing joints at reasonable spacing is one of the best ways to control cracking and make the cracks occur where you want it to rather that where it will.

The joints should be sawn in the first three days after placement of the concrete. All concrete slabs will crack. Just make sure it cracks where you want it to.

(Life Member, American Society of Civil Engineers)

[Mr_D]

During my heavy construction inspection/design days we waited 28-30 days unless highearly cement was used.