Concrete & Salt

[Bigdaddy18]

Quick question, does anyone know if you can put salt down on a concrete driveway??? I heard that you should not, wears on the concrete and causes it to chip and crack faster... Any one have any experience with it??? Do's and dont's??? Thanks for your help.

[Roofer]

I'm no expert on cement, but as far as I know, if it is regularly sealed, salt is ok. It is bad for the cement if not sealed.

[boatfixer]

The problem with salt on concrete is when the ice is melted and the water penetrates the surface of the concrete and when the water refreezes, the surface will begin to pop. Salt is not corrosive to concrete, contrary to what some people say, but it is the thaw/freeze cycles that it will go through.

If the slab was laid correctly, air entrained, the right water to cement ratio, was finished properly and was sealed correctly, the use of a moderate amount of salt will do little harm. If any of this is questionable, I would avoid using salt.

[Scupper]

Hey there,,,

before the site crashed for a couple days there was a couple of replys to this post stating not to use steel finishing tools, "Fresno" on exterior concrete work.

My question to this is what type of tools should one use?

Thanks...

[fish2live]

wood or magnesium(spell). though i don't know too many that don't hit the slab with a frezno. the proper way is to screed then hit with bull float then broom some people will hit with bull float then heffer float. a heffer float is a smaller lighter bull float.

[Scupper]

fish2live, thanks for responding to my question.

99% of concrete I have placed for nearly 40 years has been outdoors. Your explanation of procedures are as I would do it with the exception of brooming after bull floating. We have always included the Fresno/steel as a means to get the best seal of the product.

I wish one of the fellas that replied before the site crash would pipe in and give more information as to not using steel for outdoor finishing as I would surely like to learn of this. I also feel it might save future finishers from going thru shoulder repairs.

Thanks again...

[boatfixer]

The desired finish would determine whether or not one would use a fresno or not. If what you are looking for is a smoother surface, then a fresno is ok to use as long as it is not overdone. If you are looking for a brushed surface, like a side walk or driveway, (brushed for non-slip) then using a fresno is pointless. When it is suggested that using steel is bad, it is usually in reference to troweling with steel. Using a fresno while the mud is still fresh is one thing, troweling after the surface has had time to set is another. Wiping or troweling with steel after the surface has had some time to begin setting, will cause microscopic tears in the surface. This is problem with exterior concrete because of the freeze/thaw cycles and constant exposure to the elements it is subject to. Also, high quality sealers made exclusively for concrete should always be used. This is a very basic answer and I know there is more info out there that could go into much more detail than this but I hope it helps.

[Scupper]

Great information Bruce.

We always used a Fresno/steel trowel after floating, edging and jointing. Than we would broom for the non slip effect. The running joke in our network was a good broom man could make a bad finisher look good.

As I mentioned ,99% of our work was outdoors.

 Quote:

If you are looking for a brushed surface, like a side walk or driveway, (brushed for non-slip) then using a Fresno is pointless.

I respect your method and technics of limiting your use of a Fresno outdoors and sure would of loved to float and broom some of those hot loads over the years but we were always taught that using the Fresno/steel makes the concrete seal even though we would lightly broom after.

We also recommended sealers due to the climate here.

Thanks for the information.

[Shack]

Magnesium Bull Float is all I would use on exterior concrete. This in conjunction with a magnesium “mag”, a straight aluminum or wood screed, tap the form boards with a hammer, use an edger and mag for the edging, broom finish and clean your tools. I had the privilege of using the rope style broom finisher last summer and for large slabs, that thing work slicks. I also started using a 10’ power screed and still have mixed reviews about that. I think the last time the Fresno was broke out was for the inside of a garage we poured, besides that it’s not needed on exterior concrete and defiantly is another time consuming step and you end up just brooming over it. The rule I heard (a long time ago) was finishing exterior concrete with a Fresno, could lead into surface popping in the long run. Why, I do not know. It is kind of like using a finishing trowel for exterior concrete, just is not done.

As for the salt thing, I just have never used salt. I have seen what it can do to concrete that is even poured/laid correctly and is a great mix. I am not a scientist, but I just learned not use salt on concrete.

Good luck..

[fish2live]

boatfixer is right but, you can get almost the same results with a heffer float. after edging and cutting if you are going to put in tooled joints a heffer float can be used to mag out the lines.

or you can alway get the knee boards out and crawl the slab with a mag. i always try to avoid doing this because of the amount of extra work it takes.