[TowerTalk] Rebar cage - ???

[A.J. Farmer (AJ3U)]

The fiber reinforced concrete is stronger than standard concrete and
probably eliminates the need for a wire grid, but that's not the
reason you don't need rebar in a patio slab.  Concrete has high
compression strength but very little tension strength.  Rebar provides
the tension strength.  A patio slab experiences mostly compression
force and barely any tension force so the rebar is not necessary.

A pier tower base, on the other hand, will have both high tension and
high compression forces so rebar is absolutely required.

On 1/23/06, Eg9k at aol.com <Eg9k at aol.com> wrote:
> Hi all -   This past summer I had a  24' x 30' slab poured 4" thick with a 3'
> x 4' by 16' deep at one corner to build  a barbecue on it. I was surprised
> when I noticed they weren't using any rebar or  heavy wire.
> The concrete man explained that the rebar wasn't  necessary with the  new
> type concrete with the reinforcing fibers in it. He  stated he would put in the
> rebar / wire if I wanted it, but it just be a  extra expense. I explained to
> him that I had put in several pier type tower  bases over the years and had used
> the rebar. His answer to me was he didn't  think the rebar would be needed
> with the new type concrete, maybe the heavy grid  wire but not the rebar. I
> figure there is some merit to what he's telling me  because he's been in the
> concrete business for over 20 years. Something to think  about     73's   Harold

--
A.J. Farmer, AJ3U
http://www.aj3u.com