I have the need to use cement in the back country. Because it’s heavy and I’m packing it in, would it be lighter if I took it in as a powder and used lake water and mix it there? Or does the water ‘evaporate’ after it cures? Obviously it would be more convenient to mix it at home and carry the completed anchor in as a unit but I’m also concerned about the weight.
Thanks,
Pam
Don’t have a definitive answer but I’m fairly certain the water is at least partly absorbed by the mix.
water becomes part of the final concrete. dry cement and sand would carry easily in a pack frame.
My experience doing off the trail projects involving concrete we carried in the concrete mix and the water separately. I was lead by people with more experience then me, I assume if premixing it was more practical we would have done so. If you have a water source there just pack in the concrete.
Former construction material testing tech, here. Yes, the concrete absorbs virtually all the water added to the mix. In fact, the reason you keep it wet while it cures is so water doesn’t evaporate out and weaken it. That said, it forms a fairly small component of the total weight. Figure out how much concrete you need, by weight, and calculate the weight of water that went in it. If the water weight is more than you want to carry, mix there.
Numbers to use for calculating:
Concrete is usually about 145 lb/cubic foot
water is 62.4 lb/cubic foot or 8.338 lb/gal
There will be considerably less than 1 cubic foot of water in a cubic foot of concrete. Read the mix directions and estimate the percentages. Any other questions, I will check back later. I can even do the calculations for you if you give me relevant info. I used to actually make concrete mix designs.
Exactly what I needed!
Thank you for your offer but based on the calculations you provided I think I can easily assume it will be better to mix it there.
Thanks all for your time.
Concrete starts going through a chemical heat process once the water is added and will begin to set up. That is why the concrete trucks you see on the road have the whole mixer on the truck constantly rotating, once the concrete stops moving it will start hardening.
So if you mix it ahead of time you had better put it where you want it soon.
Just wanted to add, after reading OP and all responses that:
Cement is not the same as concrete.
Don’t use cement if you really need concrete and vice versa.
concrete is a mix of cement, water, fine aggregate and maybe course aggregate. cement is a dry powder.
of course i should spell coarse right. damn depending on spell check to highlight mistakes.
Absolutely correct, and one of my pet peeves when I was in the industry, but I didn’t want to be pedantic to someone who genuinely needed expertise that I had.