[TowerTalk] CONCRETE CURING

[AA6DX - Mark]

Howdy TTers ..
BACK WHEN -- B4 age, arthritis, neuropathy, weight, eyesight, etc..... 60s. 
70s, 80s ....Many many towers up .. foundation on Friday, or like that, when 
the concrete trucks were available  (methinks there was a premium if you 
insisted on Saturday delivery .. n'est-ce-pas?) --then, tower party the next 
weekend .. Saturday, or Sunday (sometimes BOTH) ..  but of course, not with 
a hurricane a blowin' ... usually, tower up Saturday, antenna system 
completed Sunday .. .never a prob .. rust on rebar was to be ignored.... (I 
was even a hoddy for one summer... ouch!) ..  and, no rebar welding .. just 
wired the cage together, as was told to do .. had the cage bent, pre-wired 
by the pros .. usually fell apart somewhat before it was settled in the hole 
..  just put it back together.  NO forms for the "hole" ... just the top, 
and those were made rigid, so as to hold the cross supports to level the 
tower base.  YOU MUST make sure the concrete in the hole has all air holes 
removed, and that it settles nicely ..  for small towers, even a 2x4 works 
.. then, having set aside some watered down `crete, keeping it from setting, 
a while after the tower was poured, used it to make a nice cap (grout) .. 
even messed with some mastic, etc... but no real improvement doing that ... 
Steve's rules generally worky worky ...
Now, for the Sabre tower/Log Periodic I erected at Fort Wainwright, AK 
(Fairbanks) .. the specs called for a longer set-up time, darned if I can 
remember, but ended up putting the last part of the monster together in the 
snow .. drop a bolt, nut, or any other small part, and ... well, you can 
guess.   Used words I did not know I knew!  Last heard, it's still standing, 
15 years later...   73, y'all  Mark Nelson  -  AA6DX

From: "NØATH" <n0ath at charter.net>
To: <towertalk at contesting.com>
Sent: Monday, August 28, 2006 6:05 PM
Subject: Re: [TowerTalk] CONCRETE CURING


At the KCPL power plant where the concrete stacks are 750 feet tall - they
said
the magic number for max strength was 28 days.  A lot of difference between
a
750 stack and a short foundation though. Not trying to add fuel - just
commenting
Dave / NØATH



I would say one week is not enough, remember the compression/tension from a
tower in wind is a lot more stressful than foundations.  I think you are
guessing, the people who poured my concrete said they always recommend 3 to
4 weeks for towers or longer for complete curing.

Mike


Most builders will cap a foundation within a week of a pour.

Lots of them  will start framing at the same time. My sense is a week
is good enough.



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