"Ralph Mowery" wrote in message
k.net...
In article , "frank says...

You need reinforcement for concrete that might come under tension as
tensile strength of concrete is only about one eighth that of
compressive strength. Number he is quoted must be compressive strength.
Apparently there are some advantages of fiber over rebar. I would tend
to take the advice of the concrete man.

I live in an area where most of the concrete men are just
local rednecks. They are very good at digging out footers
and pouring the concrete, but do not have the engineering
education . It will look like an execellent job, but I am just
not sure about how long it will last or hold up.

But presumably they do know what has happened
with most of the work they have done.

The more I read, the less I understand about the
concrete..Just like many things, too many opinions
by too many that claim to be experts.

My back gound is electronic engineering,so tend to look
at most thing as an engineer would. What looks good
and like it would work sometimes is the wrong way to go.

When I built my house on a bare block of land, doing almost
all the work myself, the operation selling the mesh for the slab
would give you the design of the slab for free if you sent them
a copy of the house plans. I just followed the instructions they
sent me to the letter. And had the hilarious result of the local
council telling the local builders to have a look at my slab before
the concrete was poured, because that is how it should be done.

They didn't bother with bar chairs which are little bits of reo
made into a 4 legged thing that holds the mesh up from the
ground so that the mesh is at the right height in the concrete.
They are a bit time consuming to use, you use a tool that
wraps wire around it and the mesh to keep it in place.

In those days there were no plastic bar chairs.

They builders do it the other way, use tool with a hook on
the bottom of it and lift the mesh once the concrete has
just been poured, The building inspectors hate that because
there is no way to check that the mesh is in the right place.