Concrete Rebar

Canarywood1 · 05-25-2012, 10:48 AM

Quote:

Originally Posted by jomama45

The "elements" may be too vague of a term. In reality, anywhere there is a chance that the slab may be subjected to moisture & freeze/thaw cycles, air entrainment is necessary. The OP stated this was a "barn", which could certainly be subjected to both of these scenarios............

As a contractor I'll always opt for a 4000 psi+ mix for hard troweled finishes. Everything else aside, it's makes fiscal sense to spend a few dollars more per yard to get a floor that finishes better & faster. IMO, pouring a 3000 psi to save a few dollars on material will cost far more in extra labor waiting for adequate concrete to finish..........

Try to sell your theory to a construction company building a high rise with 25-30,000 cu. yds. involved.

concretemasonry · 05-25-2012, 11:28 AM

Canarywood -

You are too provincial since the OP never did give an eaxact location as far as I saw. There is a worl of difference between FL where some things are acceptible but not adequate in othe locations like WY, MN and Canada. A high rise is easy, but a slab on grade in a cold climate is a different world. That is why 4000 psi in very common or normal. Of course air entrainment is not common in FL and the cost there could be jacked up if was not common.

Dick

Canarywood1 · 05-25-2012, 03:20 PM

Quote:

Originally Posted by concretemasonry

Canarywood -

You are too provincial since the OP never did give an eaxact location as far as I saw. There is a worl of difference between FL where some things are acceptible but not adequate in othe locations like WY, MN and Canada. A high rise is easy, but a slab on grade in a cold climate is a different world. That is why 4000 psi in very common or normal. Of course air entrainment is not common in FL and the cost there could be jacked up if was not common.

Dick

Your reading too many books,and assuming things,as i stated in an earlier post,i have 35 years experience in the redi-mix industry,and have worked on many major projects over the years,from high rises to tunnels,filtration plants,airport runways,you name it and i've helped build it.

jomama45 · 05-25-2012, 07:29 PM

Quote:

Originally Posted by Canarywood1

Try to sell your theory to a construction company building a high rise with 25-30,000 cu. yds. involved.

Re-read the original post, it's a "barn", not a high rise building. How you can tell the slab is protected from freeze-thaw cycles is amazign to me considerign the lack of info provided........

Quote:

Originally Posted by Canarywood1

Your reading too many books,and assuming things,as i stated in an earlier post,i have 35 years experience in the redi-mix industry,and have worked on many major projects over the years,from high rises to tunnels,filtration plants,airport runways,you name it and i've helped build it.

I think you may be underestimating Dick's knowledge and experience in the same field by just a "weee" bit................

Canarywood1 · 05-26-2012, 08:24 AM

[quote=jomama45;928691]Re-read the original post, it's a "barn", not a high rise building. How you can tell the slab is protected from freeze-thaw cycles is amazign to me considerign the lack of info provided........

Your missing the point completely, i'm refering to the money involved by increasing unneeded psi.

concretemasonry · 05-26-2012, 10:11 AM

You go with the strength required for the properties required. The points regarding the strength apply to the durability of the concrete and strength is one major factor. The money is actually minimal to raise strength since the agrregate is about the same in areas where good low absorption aggregate is common. The delivery cost is independent if the strength, placing is about the same or less with the proper slump. It is just a little more cement and attention to aggregate gradation and mix design. The days of the 3000 psi are getting pretty limited for many applications and area.

Dick