3000 psi or 5000 psi concrete
3000 psi or 5000 psi concrete
(OP)
i am building a house in waynesvile, nc (3700 elevation). Would there be an advantage to pouring the footers and basement floor with 5000 psi instead of 3000 psi concrete. the local standard is 3000 psi at 6" for the floor, however i have see a lot of cracks in basement floors in the area.





RE: 3000 psi or 5000 psi concrete
RE: 3000 psi or 5000 psi concrete
The cracking you may have seen elsewhere is probably not due to the concrete strength, but more likely due to poor subgrade compaction; lack of control joints in slabs; absence of shrinkage reinforcement; or poor curing techniques.
RE: 3000 psi or 5000 psi concrete
Is that 6" slump? If so, that seems a bit high to me. ACI recommends 3"-4" for slabs and footings. The higher water content may be a contributing to the cracking as well....
JKW
RE: 3000 psi or 5000 psi concrete
RE: 3000 psi or 5000 psi concrete
RE: 3000 psi or 5000 psi concrete
Higher strength concrete will not help and could shrink more.
The old concept of more strength means better durability, but that does not always hold and you do not have the exposure. If you do have concrete exposed (especially in a basement slab) to freezing and thawing conditions, air entrained concrete could be a good addition.
If you are worried about shrinkage, do not add excess water and keep the slump to 3" maximum even though contractors do not like to work with it. Cure prperly and slowly.
All concrete will crack and what you may have seem was really micro-cracking of the surface due to finishing and/or curing.
RE: 3000 psi or 5000 psi concrete
RE: 3000 psi or 5000 psi concrete
RE: 3000 psi or 5000 psi concrete
RE: 3000 psi or 5000 psi concrete
RE: 3000 psi or 5000 psi concrete
A masonry contractor hires masons. Masons use mortar to lay masonry units.
RE: 3000 psi or 5000 psi concrete
RE: 3000 psi or 5000 psi concrete
Around here, we have many contractors that do both and they advertise or hold themselves out to be "concrete and masonry constractors". They even hold separate industry company memberships for both trades. These contractors also have separate agreements with both unions.
We also have contractors that do only one of the trades and have no union agreements with the other unions.
RE: 3000 psi or 5000 psi concrete
Concrete is not cheap, and it's more expensive to do the second time. The foundation is the start of the build process and it's intended to outlast the rest of the building, spend your money wisely there, save money on the shingles, they are much easier to do-over in 10 years.