4 inch round posts

[tooly236]

I need some help on making some posts. I am making 4 inch round posts and I am new to concrete, if anyone could help me on the best mix and what rebar I would need. The posts will be used in mexico so frost is not a issue. The posts will not be under any tension or extreme forces. They are just to fence in a acreage. Any help would be appreciated, thanks

 

[JAE]

For a non-loading use - probably a single #4 bar down the center would suffice.

Are you hammering these into place or digging a hole and inserting them?

 

[tooly236]

Thanks for the reply, I was hoping I could get away with a single bar and not a 3 bar spread. Labour is cheap here so they will all be going in by hand.

 

[DTGT2002]

I am all for putting more concrete out in the world, but is there any particular reason you want to use a concrete post? I would think standard steel posts would be more cost efficient?

 

[tooly236]

Steel posts flex alot unless you go with a sch 40 wall or larger. Which gets pretty expensive.

 

[DTGT2002]

Fair enough, how are connecting your fencing to the posts?


With your cheap labor, I assume you are mixing your own concrete. Planning using a bag mix (quikcrete) or mixing your own with portland and local sand and gravel?


What will you use for forms? Build a reuseable wood for or cardboard throw aways?

 

[tooly236]

Yes I am mixing my own concrete, I just cut a 4 and half inch pipe in half and welded some angle iron to seperate it. I was thinking about using a 60 percent gravel to 40 percent sand mixture. Thanks for any advice.

 

[tooly236]

And I am just wrapping sheep fence around them so I am not fastening anything to the posts

 

[JAE]

Outdoor concrete - if you are in a cold climate you should also consider air entrainment to avoid freeze-thaw damage.

 

[tooly236]

I am in mexico, so if freeze becomes a issue fence posts will be the least of my concerns. Because there is very little load on the posts do you think I could get away with #3 rebar, #4 is not sold in the closest town. Thanks. And do you guys agree that a 60% gravel to 40% sand ratio is alright. I am from a hydraulic background so I know little to nothing about concrete, I am from way Northern Canada where we rarely use concrete. I will be making a bunch of other concrete items, is there any formulas to figuring out rebar.

 

[csd72]

tooly236,

We dont usually specifiy the exact concrete mix as these are usually proprietary mixes that are designed and tested by the manufacturer.

I have specified a mix on a few smaller jobs where it is mixed by hand. Cement :Sand : aggregate

1:2:4 for a nice durable mix
1:3:6 for a leaner much cheaper mix (at the sacrifice of durability)

Water content should be no more than about 60% of the cement.

 

[Horrie]

How about using 4" pvc ,grouted. I'd be interested in any comments on whether you'd need reo bar in it ,the tensile strength of the pvc seems to be pretty high and I would imagine being on the outside would have good resistance to deflection. cheap too and no rust.Iv'e used it on tap stands (4 ft high) 2" dia. pvc with fibre reo and their very solid.