going to have a new driveway poured. One of the contractors [with the best
price] said we didn't need rebar because the concrete he used has the fiber
in it. Should I insist on rebar or does the fiber negate the need for
rebar?
TIA

On Mon, 1 May 2006 11:28:54 -0400, "plug" wrote:

going to have a new driveway poured. One of the contractors [with the best
price] said we didn't need rebar because the concrete he used has the fiber
in it. Should I insist on rebar or does the fiber negate the need for
rebar?

I would suggest adding rebar to it... Fiber's great for many things,
but concrete with steel is a well proven comodity... Rebar is not that
expensive when you're buying it in the 20 ft sections... Figure out
how many you are going to need and get a price on the steel from
either a steel supply house (cheaper) or Home Depot (not as cheap, but
not that bad of a price either)... Ask the contractor how much he
would add to the price for the rebar... If the amount that he added is
not reasonable, just have him build the forms one day and pour the
concrete a few days later... Laying rebar is easy, you can do it
yourself without any help...

plug wrote:
going to have a new driveway poured. One of the contractors [with
the best price] said we didn't need rebar because the concrete he
used has the fiber in it. Should I insist on rebar or does the fiber
negate the need for rebar?
TIA

I would also suggest the steel. Fiber will make the concrete stronger
and in some cases can substitute for steel, but I would still want the
steel. You also may want to check your local codes and they may require
rebar.


--
Joseph Meehan

Dia duit

I would also get the rebar.

Can one *add* this fibre to ready-mix in bags?
I think Modern Marvels should this fibred-up 'crete--*much* greater bending
w/o cracking.
--
Mr. P.V.'d
formerly Droll Troll
"Joseph Meehan" wrote in message
...
plug wrote:
going to have a new driveway poured. One of the contractors [with
the best price] said we didn't need rebar because the concrete he
used has the fiber in it. Should I insist on rebar or does the fiber
negate the need for rebar?
TIA

I would also suggest the steel. Fiber will make the concrete stronger
and in some cases can substitute for steel, but I would still want the
steel. You also may want to check your local codes and they may require
rebar.


--
Joseph Meehan

Dia duit

By "control joints" do you mean expansion joints?
Can you elaborate more on both? Perhaps more toward pouring a shop floor on
foundation earth.
--
Mr. P.V.'d
formerly Droll Troll
"Rudy" wrote in message
news:NOr5g.103608$P01.24114@pd7tw3no...
going to have a new driveway poured. One of the contractors [with the
best price] said we didn't need rebar because the concrete he used has
the fiber in it. Should I insist on rebar or does the fiber negate the
need for rebar?

Thats why he had the best price..the least work. For a smaller slab like a
patio, for foot traffic, I'd go with fiber. Our patio slab has rebar in
it because a 3000 lb hot tub is going to be set on it soon. For a driveway
which has to bear the weight of vehicles, I'd use rebar, 1/2" dia. spaced
2 feet apart and wire tied at least every second "+". We did ours a last
June and I did all the prep work: levelled the soil, spread 2-4" gravel
(to get the slope right) and used a rented compactor over it all. Then
went with 1/2" rebar, 24" OC. The China building syndrome has driven the
price of nearly every building material up and rebar is no different. I
got a deal on 20' (6 meter) lengths @ $ 4.00 Used 80 pieces. I see it
for $ 5.00 now
We went with ~10 yards of 3500 lb concrete, 4" thick (not the 3.5" of a
2X4). After we did the "plain" concrete ~ 45' X 17', I stripped & moved
my side forms "out" 18" and re set them, then dropped two rows of rebar
in, crosstied every 4' and poured an 18" wide accent strip that was
ordered in 'exposed aggregate' down each side of the original DW. Also
did an exposed sidewalk up to the house/steps which were 'ag' also. I
recently drove our 12,000 lb RV and 7500 lb pickup over the exposed 'edge'
for the first time and no cracks. BTW, this driveway incorporates a 90 o
curve so the forms were 2 layers of 3/8" plywood with plenty of stakes.

I should add that many concrete 'experts' say that all concrete will crack
and that the rebar just holds it together. On a driveway, the control
joints may or may not crack..depends on how good the prep work was IMO

R

PS, make sure the rebar is supported before/during the pour. It needs to
be "in" the slab, not laying on the ground. Watch the whole process
carefully and you can do your own small jobs like sidewalks and slabs next
time...Its not rocket science. If you're going to give it a try, start
small.

I was also thinking that one of the reasons I would prefer rebar is
bacause at least that way, you know what you are getting. With the
fiber you probably can't tell by looking at it (can you?).

By "control joints" do you mean expansion joints?
Can you elaborate more on both? Perhaps more toward pouring a shop floor
on foundation earth.

I'm referring to the ~1" deep lines placed across (outdoor) slabs of
concrete like driveways or sidewalks with the intent of their cracking along
the line 'control joints'...trying to control where the cracks will appear
(if in the event they do)
To me, "Expansion joint" is a black fiber product placed between adjacent
slabs which arent touching to allow for expansion and contraction.
They are seen between sidewalk slabs around here.
Then there are the ones inside in a garage/shop slab that are sometimes not
visible but still intended for the crack(s) to develop there later.

Two garages back, they put these in the slab. It never cracked. This last
one, they just cut the concrete. It hasnt cracked either 3 yrs later.

R

Then there is the metal expansion joint placed in stucco walls..

I was also thinking that one of the reasons I would prefer rebar is
bacause at least that way, you know what you are getting. With the
fiber you probably can't tell by looking at it (can you?).

Oh yes, you can see it if you re there. Picture a bunch of inch long chopped
fiberglass tufts. You can see them sticking out while the crete is being
poured and also after its floated..they still stick out but to a lesser
degree. I saw one recently where they poured a hot tub slab, I said I
wouldnt want all those tufts sticking out of my slab (it was a broom
finish). I was told they wear or break off later and disappear...maybe they
do

R

I had a section of a driveway replaced 16 years ago and still not a sign of
any cracks. It had fiber in it and no rebar. This is in Memphis. Perhaps it
is different in a colder climate.
Several years ago one of the do-it-yourself magazines recommended using both
rebar and fiber. As I recall they were saying the fibers prevented small
cracks which could develop into large cracks and the rebar was for support
against major cracks from heavy loads.


"plug" wrote in message
...
going to have a new driveway poured. One of the contractors [with the best
price] said we didn't need rebar because the concrete he used has the fiber
in it. Should I insist on rebar or does the fiber negate the need for
rebar?
TIA

I was told they wear or break off later and disappear...maybe they do

My driveway is 2 months old and there is still fuzz sticking out

More driving more driving ! G But normal folk dont drive on ALL their
square feet of driveway anyway..I wonder how many seasons they'll last.

"Rudy" wrote in message
news:zov5g.104631$WI1.43962@pd7tw2no...
I was told they wear or break off later and disappear...maybe they do

My driveway is 2 months old and there is still fuzz sticking out

More driving more driving ! G But normal folk dont drive on ALL their
square feet of driveway anyway..I wonder how many seasons they'll last.

Get a giant razor, or a 55 gallon drum of Nair.....
:^/

aem sends....

"Rudy" wrote in message
news:zov5g.104631$WI1.43962@pd7tw2no...
I was told they wear or break off later and disappear...maybe they do

My driveway is 2 months old and there is still fuzz sticking out

More driving more driving ! G But normal folk dont drive on ALL their
square feet of driveway anyway..I wonder how many seasons they'll last.



I bet they could be burned off with a torch. Just a flash mind you, too
much heat and the concrete will spall (chip) and leave scorch marks
especially if it is still new. I'd wait at least 6 months before looking to
remidiate the fuzz. Sunlight and a few more months might be enough to
degrade the fuzz sticking out. Don't use a sealer until you understand what
it will do to the fuzz (like make it stick down and last forever)

Mechanically speaking fibers continuously spanning every cubic inck of the
bulk material would have far greater strenghth than a metal bar every 2
feet. You save on labor for sure but as I recall, the fibegglass add-in is
quite expensive in its own right.

yes, i have added fibers to small batches. just throw it in the mixer.
not gonna find it at HD. try a concrete supplier.

Mebbe even a floor sander, would smooth out the 'crete as well.
Or belt sander.
--
Mr. P.V.'d
formerly Droll Troll
"PipeDown" wrote in message
ink.net...

"Rudy" wrote in message
news:zov5g.104631$WI1.43962@pd7tw2no...
I was told they wear or break off later and disappear...maybe they do

My driveway is 2 months old and there is still fuzz sticking out

More driving more driving ! G But normal folk dont drive on ALL their
square feet of driveway anyway..I wonder how many seasons they'll last.



I bet they could be burned off with a torch. Just a flash mind you, too
much heat and the concrete will spall (chip) and leave scorch marks
especially if it is still new. I'd wait at least 6 months before looking
to remidiate the fuzz. Sunlight and a few more months might be enough to
degrade the fuzz sticking out. Don't use a sealer until you understand
what it will do to the fuzz (like make it stick down and last forever)

Mechanically speaking fibers continuously spanning every cubic inck of the
bulk material would have far greater strenghth than a metal bar every 2
feet. You save on labor for sure but as I recall, the fibegglass add-in
is quite expensive in its own right.