I am going to have some concrete poured on some ground with a slope.
This is for one of the carport type garages. It will be about 24 x 25
feet.

One end will be at ground level and slightly slope down for about 10
feet, from there it will go down about 4 feet. The plan is to build a
cinder block wall and fill it with rock or whatever. Then pour a 4 foot
floor.

Some are saying the fiber is not needed and some say to put the fiber
in. There will be some rebar in it, but not too much. The concrete man
wants to use the fiber instead of the wire that is often used that is
about 4 inches square.

Does the fiber make the concrete much better ? I think the man said
he used 3500 psi concrete.

I looked at one place on line and it seems there is not but about 3 or 4
dollars a yard each time you go up another 500 psi. Is this correct ?
For no more than I am going to use ( even if it is 20 or 30 yards) it
would only cost another hundred or two dollars to go up a grade or two.
Would it be worth it to go to more than the 3500 psi grade ? I have an
estimate of about $ 15,000 so an extra 2 or 3 hundred is no big deal.

On 9/12/2020 11:05 AM, Ralph Mowery wrote:


I am going to have some concrete poured on some ground with a slope.
This is for one of the carport type garages. It will be about 24 x 25
feet.

One end will be at ground level and slightly slope down for about 10
feet, from there it will go down about 4 feet. The plan is to build a
cinder block wall and fill it with rock or whatever. Then pour a 4 foot
floor.

Some are saying the fiber is not needed and some say to put the fiber
in. There will be some rebar in it, but not too much. The concrete man
wants to use the fiber instead of the wire that is often used that is
about 4 inches square.

Does the fiber make the concrete much better ? I think the man said
he used 3500 psi concrete.

I looked at one place on line and it seems there is not but about 3 or 4
dollars a yard each time you go up another 500 psi. Is this correct ?
For no more than I am going to use ( even if it is 20 or 30 yards) it
would only cost another hundred or two dollars to go up a grade or two.
Would it be worth it to go to more than the 3500 psi grade ? I have an
estimate of about $ 15,000 so an extra 2 or 3 hundred is no big deal.



I've heard many good things about fiber, never heard a downside. Helps
avoid cracjing.

3500 psi should be adequate. You could probably get away with less but
not worth the small savings.

On 9/12/2020 11:37 AM, Ed Pawlowski wrote:
On 9/12/2020 11:05 AM, Ralph Mowery wrote:


I am going to have some concrete poured on some ground with a slope.
This is for one of the carport type garages.Â* It will be about 24 x 25
feet.

One end will be at ground level and slightly slope down for about 10
feet, from there it will go down about 4 feet.Â* The plan is to build a
cinder block wall and fill it with rock or whatever.Â* Then pour a 4 foot
floor.

Some are saying the fiber is not needed and some say to put the fiber
in.Â* There will be some rebar in it, but not too much.Â* The concrete man
wants to use the fiber instead of the wire that is often used that is
about 4 inches square.

Does the fiber make the concrete muchÂ* better ?Â*Â* I think the man said
he used 3500 psi concrete.

I looked at one place on line and it seems there is not but about 3 or 4
dollars a yard each time you go up another 500 psi.Â* Is this correct ?
For no more than I am going to use ( even if it is 20 or 30 yards) it
would only cost another hundred or two dollars to go up a grade or two.
Would it be worth it to go to more than the 3500 psi grade ?Â* I have an
estimate of about $ 15,000 so an extra 2 or 3 hundred is no big deal.



I've heard many good things about fiber, never heard a downside.Â* Helps
avoid cracjing.

3500 psi should be adequate.Â* You could probably get away with less but
not worth the small savings.

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.

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. 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.

On Sat, 12 Sep 2020 11:05:13 -0400, Ralph Mowery
wrote:



I am going to have some concrete poured on some ground with a slope.
This is for one of the carport type garages. It will be about 24 x 25
feet.

One end will be at ground level and slightly slope down for about 10
feet, from there it will go down about 4 feet. The plan is to build a
cinder block wall and fill it with rock or whatever. Then pour a 4 foot
floor.

Some are saying the fiber is not needed and some say to put the fiber
in. There will be some rebar in it, but not too much. The concrete man
wants to use the fiber instead of the wire that is often used that is
about 4 inches square.

Does the fiber make the concrete much better ? I think the man said
he used 3500 psi concrete.

I looked at one place on line and it seems there is not but about 3 or 4
dollars a yard each time you go up another 500 psi. Is this correct ?
For no more than I am going to use ( even if it is 20 or 30 yards) it
would only cost another hundred or two dollars to go up a grade or two.
Would it be worth it to go to more than the 3500 psi grade ? I have an
estimate of about $ 15,000 so an extra 2 or 3 hundred is no big deal.



Fiber might help a little but it is no replacement for steel.

On 9/12/20 10:05 AM, Ralph Mowery wrote:


I am going to have some concrete poured on some ground with a slope.
This is for one of the carport type garages. It will be about 24 x 25
feet.

One end will be at ground level and slightly slope down for about 10
feet, from there it will go down about 4 feet. The plan is to build a
cinder block wall and fill it with rock or whatever. Then pour a 4 foot
floor.

Some are saying the fiber is not needed and some say to put the fiber
in. There will be some rebar in it, but not too much. The concrete man
wants to use the fiber instead of the wire that is often used that is
about 4 inches square.

Does the fiber make the concrete much better ? I think the man said
he used 3500 psi concrete.

I looked at one place on line and it seems there is not but about 3 or 4
dollars a yard each time you go up another 500 psi. Is this correct ?
For no more than I am going to use ( even if it is 20 or 30 yards) it
would only cost another hundred or two dollars to go up a grade or two.
Would it be worth it to go to more than the 3500 psi grade ? I have an
estimate of about $ 15,000 so an extra 2 or 3 hundred is no big deal.

Do they plan to put in at least one solid rebar for grounding
purposes? Bend it if necessary and leave maybe 3" sticking out to
connect ground wire. The NEC says at least 20' so it should be wired to
at least one other piece.
There's an article here about just leaving some rebar sticking out
of the concrete.
https://www.ecmag.com/section/codes-standards/electrical-service-grounding-option-steel-rebar-sticking-out-method
OR
https://preview.tinyurl.com/yybssjf2

It's also called a Ufer ground after the man who invented it. It's
better than a ground rod if done properly.

In article , says...
Do they plan to put in at least one solid rebar for grounding
purposes? Bend it if necessary and leave maybe 3" sticking out to
connect ground wire. The NEC says at least 20' so it should be wired to
at least one other piece.
There's an article here about just leaving some rebar sticking out
of the concrete.
https://www.ecmag.com/section/codes-standards/electrical-service-grounding-option-steel-rebar-sticking-out-method
OR
https://preview.tinyurl.com/yybssjf2

It's also called a Ufer ground after the man who invented it. It's
better than a ground rod if done properly.





I have heard of the Ufer ground. However I do not want any rebar
sticking out of the concrete. It tends to swell up and bust up the
concrete.

It does not matter anyway as there is not going to be any electricity
going to the building. It is going to be about 70 feet from the house.
If I do want to power up something, I will just run a dropcord from the
house to it. I had thought of putting some powered doors on it, but it
would have been about $ 2000 more not counting on having to run the
electrical service to it. I am thiking of getting a propane or
propane/gas generator and leaving it out there, but I have a 3.5 kw one
I could roll out there if I really wanted to.

I did have another thougth of powering the roll up doors with a battery
and solar charger.

"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.

On 9/12/20 12:52 PM, Ralph Mowery wrote:
In article , says...
Do they plan to put in at least one solid rebar for grounding
purposes? Bend it if necessary and leave maybe 3" sticking out to
connect ground wire. The NEC says at least 20' so it should be wired to
at least one other piece.
There's an article here about just leaving some rebar sticking out
of the concrete.
https://www.ecmag.com/section/codes-standards/electrical-service-grounding-option-steel-rebar-sticking-out-method
OR
https://preview.tinyurl.com/yybssjf2

It's also called a Ufer ground after the man who invented it. It's
better than a ground rod if done properly.





I have heard of the Ufer ground. However I do not want any rebar
sticking out of the concrete. It tends to swell up and bust up the
concrete.

It does not matter anyway as there is not going to be any electricity
going to the building. It is going to be about 70 feet from the house.
If I do want to power up something, I will just run a dropcord from the
house to it. I had thought of putting some powered doors on it, but it
would have been about $ 2000 more not counting on having to run the
electrical service to it. I am thiking of getting a propane or
propane/gas generator and leaving it out there, but I have a 3.5 kw one
I could roll out there if I really wanted to.

I did have another thougth of powering the roll up doors with a battery
and solar charger.


Another option is to put at least 20' of copper wire in the
concrete. It has to be at least #4 or larger. One could easily bring
that up inside of where the walls will be. And, of course, you can
always put in the old, faithful ground rod if you change your mind.
We had to install ground rods or their equivalent on center pivots
even if they were going to be powered by a generator and not connected
to commercial power. The generators would be there constantly though.
I don't know if that would apply to your situation.

On 9/12/2020 1:01 PM, Ralph Mowery wrote:
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. 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.


I'm a retired chemist and did a lot of work with composites but am not
familiar with cement except as a home owner. The cement guy may not
know that much but did talk about compressive strength which I would
think few would know about. Irregardless, I think most agree that you
are better with reinforced concrete.

In article , says...
Another option is to put at least 20' of copper wire in the
concrete. It has to be at least #4 or larger. One could easily bring
that up inside of where the walls will be. And, of course, you can
always put in the old, faithful ground rod if you change your mind.
We had to install ground rods or their equivalent on center pivots
even if they were going to be powered by a generator and not connected
to commercial power. The generators would be there constantly though.
I don't know if that would apply to your situation.



I do not know the fine points of the NEC but just to run some power for
a couple of hours I am not going to worry about it.

I worked around enough electricity at a large plant and dealt a lot with
480 votl 3 phase equipment that some of it was fused at 300 or more
amps, so not worried about how to do it safely even if it does not meet
the NEC.

If at some later date I decide to run perment power to the garage I will
make sure it meets the NEC.

For now it is going to be mainly storage. My wife just bought a small
car so she could drive it better than our larger Toyota Camry. I have
a truck that I do not drive very much unless I want to haul something
so it may sit for a week or two. That goes in the two car size garage
along with my riding lawn mower and other yard items that is about to
over flow two smaller buildings

In article , "frank says...

I'm a retired chemist and did a lot of work with composites but am not
familiar with cement except as a home owner. The cement guy may not
know that much but did talk about compressive strength which I would
think few would know about. Irregardless, I think most agree that you
are better with reinforced concrete.



I have not researched what the numbers really mean, but anyone that
works with concrete will know there are several strengths and that is
how you order it. The 3500 mix is usually the standard for 4 to 6 inch
garage floors and driveways at peoples homes. For the simple slabs
like I want, I guess most anything would work for a while, but I would
like to make sure it will hold up for many years.



A friend has a garage and the ground/rock base under it has sunk down in
parts as you can tell as you go across it. So far it has held up and
not cracked and sank down. As I am going to have about 4 feet of rocks
or something under a good portion of the slab I do not want to take a
chance of it breaking and falling in or down for an inch or three.
Along with the fiber he did say something about putting in some rebar.
I doubt he will put in very much,but I thought I read somewhere years
ago that it really needs about 10% rebar. That is a lot.

Sometimes even the concrete pros get mixed up. A friend had a
retaining wall about 6 feet high and 20 or 30 feet long built. The
concrete that filled the blocks had something added to it to slow down
the curing and something else for strength. Whatever they did, that
concrete did not cure correctly and after 2 months you could push the
cinder blocks out by hand if not for the rebar that was vertically in
them. The wall had to be taken down and rebuilt at the expense of the
concrete company.

On Sat, 12 Sep 2020 13:52:28 -0400, Ralph Mowery
wrote:

In article , says...
Do they plan to put in at least one solid rebar for grounding
purposes? Bend it if necessary and leave maybe 3" sticking out to
connect ground wire. The NEC says at least 20' so it should be wired to
at least one other piece.
There's an article here about just leaving some rebar sticking out
of the concrete.
https://www.ecmag.com/section/codes-standards/electrical-service-grounding-option-steel-rebar-sticking-out-method
OR
https://preview.tinyurl.com/yybssjf2

It's also called a Ufer ground after the man who invented it. It's
better than a ground rod if done properly.





I have heard of the Ufer ground. However I do not want any rebar
sticking out of the concrete. It tends to swell up and bust up the
concrete.

It does not matter anyway as there is not going to be any electricity
going to the building. It is going to be about 70 feet from the house.
If I do want to power up something, I will just run a dropcord from the
house to it. I had thought of putting some powered doors on it, but it
would have been about $ 2000 more not counting on having to run the
electrical service to it. I am thiking of getting a propane or
propane/gas generator and leaving it out there, but I have a 3.5 kw one
I could roll out there if I really wanted to.

I did have another thougth of powering the roll up doors with a battery
and solar charger.


They typically turn that rebar up inside a wall. The other option is a
short piece of #4 copper.
This is a UFER in a Florida building (code now).

http://gfretwell.com/electrical/ufer.jpg

On Sat, 12 Sep 2020 15:19:30 -0500, Dean Hoffman
wrote:

On 9/12/20 12:52 PM, Ralph Mowery wrote:
In article , says...
Do they plan to put in at least one solid rebar for grounding
purposes? Bend it if necessary and leave maybe 3" sticking out to
connect ground wire. The NEC says at least 20' so it should be wired to
at least one other piece.
There's an article here about just leaving some rebar sticking out
of the concrete.
https://www.ecmag.com/section/codes-standards/electrical-service-grounding-option-steel-rebar-sticking-out-method
OR
https://preview.tinyurl.com/yybssjf2

It's also called a Ufer ground after the man who invented it. It's
better than a ground rod if done properly.





I have heard of the Ufer ground. However I do not want any rebar
sticking out of the concrete. It tends to swell up and bust up the
concrete.

It does not matter anyway as there is not going to be any electricity
going to the building. It is going to be about 70 feet from the house.
If I do want to power up something, I will just run a dropcord from the
house to it. I had thought of putting some powered doors on it, but it
would have been about $ 2000 more not counting on having to run the
electrical service to it. I am thiking of getting a propane or
propane/gas generator and leaving it out there, but I have a 3.5 kw one
I could roll out there if I really wanted to.

I did have another thougth of powering the roll up doors with a battery
and solar charger.


Another option is to put at least 20' of copper wire in the
concrete. It has to be at least #4 or larger. One could easily bring
that up inside of where the walls will be. And, of course, you can
always put in the old, faithful ground rod if you change your mind.
We had to install ground rods or their equivalent on center pivots
even if they were going to be powered by a generator and not connected
to commercial power. The generators would be there constantly though.
I don't know if that would apply to your situation.

It doesn't even need to be 20' of #4, Just enough to get from a
concrete listed acorn on the rebar up to where you can connect it to
your service disconnect enclosure bus.

On 9/12/2020 6:16 PM, Ralph Mowery wrote:
In article , "frank says...

I'm a retired chemist and did a lot of work with composites but am not
familiar with cement except as a home owner. The cement guy may not
know that much but did talk about compressive strength which I would
think few would know about. Irregardless, I think most agree that you
are better with reinforced concrete.



I have not researched what the numbers really mean, but anyone that
works with concrete will know there are several strengths and that is
how you order it. The 3500 mix is usually the standard for 4 to 6 inch
garage floors and driveways at peoples homes. For the simple slabs
like I want, I guess most anything would work for a while, but I would
like to make sure it will hold up for many years.



A friend has a garage and the ground/rock base under it has sunk down in
parts as you can tell as you go across it. So far it has held up and
not cracked and sank down. As I am going to have about 4 feet of rocks
or something under a good portion of the slab I do not want to take a
chance of it breaking and falling in or down for an inch or three.
Along with the fiber he did say something about putting in some rebar.
I doubt he will put in very much,but I thought I read somewhere years
ago that it really needs about 10% rebar. That is a lot.

Sometimes even the concrete pros get mixed up. A friend had a
retaining wall about 6 feet high and 20 or 30 feet long built. The
concrete that filled the blocks had something added to it to slow down
the curing and something else for strength. Whatever they did, that
concrete did not cure correctly and after 2 months you could push the
cinder blocks out by hand if not for the rebar that was vertically in
them. The wall had to be taken down and rebuilt at the expense of the
concrete company.

From what I read you are correct. That strength is standard for home
owners and can go up to 10,000 psi for industrial use. Steel, glass,
Kevlar can go considerably higher and their tensile strengths even go
much higher. That is why you add fibers of steel or other materials to
concrete as its tensile strength is only 10-20% of its compressive strength.

https://www.engineeringtoolbox.com/c...es-d_1223.html

I note flex strength of concrete is also very low which is where bending
it like when ground shrinks below it leads to fracture.

On Sat, 12 Sep 2020 19:43:06 -0400, Frank "frank wrote:

On 9/12/2020 6:16 PM, Ralph Mowery wrote:
In article , "frank says...

I'm a retired chemist and did a lot of work with composites but am not
familiar with cement except as a home owner. The cement guy may not
know that much but did talk about compressive strength which I would
think few would know about. Irregardless, I think most agree that you
are better with reinforced concrete.



I have not researched what the numbers really mean, but anyone that
works with concrete will know there are several strengths and that is
how you order it. The 3500 mix is usually the standard for 4 to 6 inch
garage floors and driveways at peoples homes. For the simple slabs
like I want, I guess most anything would work for a while, but I would
like to make sure it will hold up for many years.



A friend has a garage and the ground/rock base under it has sunk down in
parts as you can tell as you go across it. So far it has held up and
not cracked and sank down. As I am going to have about 4 feet of rocks
or something under a good portion of the slab I do not want to take a
chance of it breaking and falling in or down for an inch or three.
Along with the fiber he did say something about putting in some rebar.
I doubt he will put in very much,but I thought I read somewhere years
ago that it really needs about 10% rebar. That is a lot.

Sometimes even the concrete pros get mixed up. A friend had a
retaining wall about 6 feet high and 20 or 30 feet long built. The
concrete that filled the blocks had something added to it to slow down
the curing and something else for strength. Whatever they did, that
concrete did not cure correctly and after 2 months you could push the
cinder blocks out by hand if not for the rebar that was vertically in
them. The wall had to be taken down and rebuilt at the expense of the
concrete company.

From what I read you are correct. That strength is standard for home
owners and can go up to 10,000 psi for industrial use. Steel, glass,
Kevlar can go considerably higher and their tensile strengths even go
much higher. That is why you add fibers of steel or other materials to
concrete as its tensile strength is only 10-20% of its compressive strength.

https://www.engineeringtoolbox.com/c...es-d_1223.html

I note flex strength of concrete is also very low which is where bending
it like when ground shrinks below it leads to fracture.

There is still a lot of 2500 or 3000 PSI concrete used but the 3500 is
usually made with pea gravel so you can pump it and that makes it more
attractive. Most concrete gets pumped from what I see here. In round
numbers one extra bag of portland (94# more per yard) adds 500 PSI. It
is a little more complicated than that but not a bad rule of thumb. My
policy has been, much greater than 2 yards that you can't place
directly from the truck, I am getting a pump. Obviously for tie beam
and cell pours, you get a pump.