# Pouring a Steep Driveway



## Rybit (Jul 23, 2008)

Anyone with any experiences? I have a fairly steep gravel driveway. I keep thinking that I'll find the money to have it paved or poured one of these days. If I go with ready mix, I will assemble a small crew and do it all myself. 

I've poured many footers, sidewalks, accessible ramps for wheelchairs, curbs, and even been involved with slab work. But I have never been involved on a steep grade pour myself.

Any thoughts are appreciated.


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## Chris Johnson (Apr 19, 2007)

What's there to know? Set your forms, grade stakes and pour, what are you looking at 6" thick? I've done 45 degrees before with no issues, just don't try a 7" or greater slump, gravity will bring it to the road, 4 or 5 " slump is fine.


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## Railman (Jan 19, 2008)

Chris Johnson said:


> What's there to know? Set your forms, grade stakes and pour, what are you looking at 6" thick? I've done 45 degrees before with no issues, just don't try a 7" or greater slump, gravity will bring it to the road, 4 or 5 " slump is fine.


Unless concrete specs have changed, slump is measured with a cone. Fill the cone, invert, & dump. The higher it stacks, the higher the slump number, & the stiffer it is. A 7 slump would stack 7" high, & a 3 would only stack 3" high. 

A 5 is pretty stiff, or maybe 6 slump is about as stiff as you want to work with for a driveway. Just be sure to explain what your doing with it when you order so the driver don't add extra on the way to job. They have a tendency to want to dump, & go. Have fun screeding the dry slump! You might want to consider a vibrating screed.
Joe


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## Kgmz (Feb 9, 2007)

Railman said:


> Unless concrete specs have changed, slump is measured with a cone. Fill the cone, invert, & dump. The higher it stacks, the higher the slump number, & the stiffer it is. A 7 slump would stack 7" high, & a 3 would only stack 3" high.
> 
> A 5 is pretty stiff, or maybe 6 slump is about as stiff as you want to work with for a driveway. Just be sure to explain what your doing with it when you order so the driver don't add extra on the way to job. They have a tendency to want to dump, & go. Have fun screeding the dry slump! You might want to consider a vibrating screed.
> Joe


 
You have it partially right.

True the higher the stack is the stiffer the concrete mix. But you do not measure the height of the stack to get the number. You use get the number from how far down the stack has fallen. Basically you take the number from the top of the cone to the height of the stack. If the stack is 3" shorter than the cone then it is a 3" slump, if it is 6" shorter than the cone then you have a 6" slump. 

So smaller number = stiffer mix, larger number = runnier mix.


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## Railman (Jan 19, 2008)

Chriss, & Kgmz...Your right!
I was told otherwise 30 years ago, & have been wrong all this time!
http://www.polysteel.com/manual/ps3000/ps3000m141.pdf

Joe


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