Cold, cold questions

[Steve B]

I went to my cabin over the weekend to check on things. It is at 7500', and it had about a foot of snow around it. Everything was fine, save that we had to walk through the snow for the last 1/8 mile.

I am anxious for spring to begin some repairs and some new work.

My question is about concrete.

I have lived most of my life in the Southern Nevada desert. The biggest problem we have had with problems is that it dries too fast.

I have noticed in that part of the country that the concrete varies wildly. Some of it looks great after years, and some of it is flaking off and the aggregate showing. Some looks good, and some looks like crap.

Part of what I want to do involves some concrete works. Some steps, and some flat work.

What's the secret to getting concrete that will last through freeze and thaw cycles? There is no real problem with frost heave in this part of the country. Is it the mix, the sack content? The aggregate? The working of the concrete? Is it best to buy delivered concrete, or will doing it yourself be okay if you do it right?

Or do I just resign myself to the fact that as it ages, it peels off?

I like doing things once, and would like to do the best from the start so it lasts the longest.

Thanks in advance.

Steve

[hallerb]

mixed well on the dry side, LONG CURE, and a little luck, get someone experienced to help you the first time. lay in cool weathewr but not freezing.

If your doing more than a yard or two its easier and cheaper to get it delivered, from a concrete truck

sakretew bag mix is very expensive

you can get additives

[Pat]

Air-entrained concrete helps in cold weather and must be delivered.

[George E. Cawthon]

Concrete lasts a long time if you mix it right and let it cure correctly. Mix wrong and cure wrong and you spalling (peeling off) poor strength, etc.

Get a good book and then mix and lay it like the book tells you.

If you want really good stuff mix six bag concrete which is water proof (6 sacks of cement per cubic yard), mix with the correct mixture of rock and sand (often sold as "road mix"), mix with the correct amount of water (will appear pretty dry), get the voids out when you lay it and don't work the surface very much.

[Joseph Meehan]

Steve B wrote: ...

The right mix is important. a book will give you the specs. Don't get it too wet, as common problem and try for a long cure (don't let it dry out, it absorbs moisture as it cures). However I noticed that only George has yet has addressed working it. Over working it is a common problem with inexperienced people. In the typical job, you want to work it a little to bring some cream to the top, but too much will make it weak and it will soon do that flaking off that you have noticed.

[TH]

[EXT]

By the way, if you have freeze/thaw cycles, you will have frost heaving. This means solid foundations below the frost line. In flat work such as sidewalks, this means a good well drained base under the concrete. Even with all the precautions, some frost damage is inevitable, here in Canada we see it all the time, despite a lot of fancy engineering to prevent it.

[Rick]

You MUST use air entrained concrete to prevent freeze/thaw spalling and other damage.

Rick

[hallerb]

sealing with thompsons water seal helps a lot, it keeps water from entering the concrete, freezing once its inside causes much spalling