[TowerTalk] concrete

[Jim Thomson]

Date: Fri, 1 Nov 2013 11:49:22 -0700 (PDT)
From: Rex Turvin <turvin2009 at yahoo.com>
To: towertalk <towertalk at contesting.com>
Subject: [TowerTalk] concrete


###  Don’t mess with anything less than 4350 psi.....and 5000 is the real ticket.    The stronger the mix, the less porous the concrete is.  
You wont get all the hairline cracks in it  with the stronger mixs.     Avoid forms in the ground like the plague if you can.   You will spend a
fortune in wood, then they will have to be removed.  Backfilling the concrete is a pita.   If not done right, you will end up with disturbed soil. 
It has to be done in  6 inch lifts, and well compacted with each lift.....pita. 

##  another unique trick a contractor showed me, was to use some cheap 2-6 mil thick plastic sheeting.......and  line all 4 x sides of the hole with it,
but NOT the bottom.   Then  while curing, nothing will leach out the 4 x sides......esp into soil.    Mine was rock hard clay top to bottom,  
hole is 9 feet deep, so didn’t bother.  

##  I covered the top of the finished concrete with some old bedsheets....and lightly sprayed water every hr.... the idea is to keep the top moist, as the
top of the concrete will want to suck in a LOT of water  during the curing process. 

##  Don’t go cheap on rebar either....... use  60 ksi stuff.....and not the 40 ksi junk.    You can get either version in weldable......or unweldable. 

Jim   VE7RF



I'm going to be pouring concrete for my base foundation and 3 guy anchors next week.  Does anyone know how long I need to let it cure before I start erecting the tower?
73 NR6M

?
ex: KF7NMD


Sincerely,


Rex Turvin
www.nr6m.com