How come some concrete is pitted from winter salt and some isn't?

[sixdogs]

I don't understand why my neighbor's garage pad is all pitted and flaking from winter salt corrosion yet the concrete pads at the gas station look as good as the day they were poured. Is it merely the PSI strength of the mix or some dark masonary secret?

[/pine]

most likely too much potash in the mix...

I used to bid on a lot seawall contracts and the specs always called for NO potash in the concrete...something to do with the salt...

[vtsnowedin]

You got it, the psi strength of the good stuff is above 4000 psi and your neighbors pad is probaly around 2500. All it takes is adding too much water to make it easy to level to weaken it.

[vtsnowedin]

most likely too much potash in the mix...

I used to bid on a lot seawall contracts and the specs always called for NO potash in the concrete...something to do with the salt...

Do you mean fly ash? Potash is fertiliser and not part of any concrete mix I know of.

[2LaneCruzer]

You got it, the psi strength of the good stuff is above 4000 psi and your neighbors pad is probaly around 2500. All it takes is adding too much water to make it easy to level to weaken it.

Ahah! That's what the problem was. My driveway, after it was about 10 years old, looked like it had been strafed by a squadron of A-10's. My new one ($$$$), about 14 years old, looks like new, save for a couple small cracks.

[/pine]

Do you mean fly ash? Potash is fertiliser and not part of any concrete mix I know of.

Yes did mean fly ash...

[MossRoad]

Also, it may not have been sealed properly.

[Egon]

The finisher may also have a little influence.

[sixdogs]

The gas station has concrete everywhere and zero pitting. The neighbor has a brush finish and all kinds of pitting.
Is it just in the PSI strength?
All of it came from a concrete plant and smart people put both surfaces down so....?

[MossRoad]

Theres many reasons.
Ground too dry when poured.
Concrete sprayed with too much water when cured.
No sealer.
Etc...