[Antennas] RE: Concrete To Use For Your Tower

[Lofstead, Jerry]

I can vouch for that  The last hole was 3 feet square and 6 feet deep.
I hand mixed 2+ yards of 15,000 PSI concrete for it.  I found muscle
aches that I never knew you could have.  I had the dump truck dump the
sand and "large" gravel/rock in the driveway and had to move it over to
the "hole", about 100 feet.  What a job!  At the time, there was a
shortage of Portland Cement and I had to buy bags any where I could find
them over a 3 month period.  Ended up with about 30 bags of cement and
lots of elbow grease to mix it all.  The tower stayed up in 125 MPH
hurricane winds in Miami, FL.  Well worth the effort.

Now that I am retiring the end of this week, I need to do it again here
in Georgia 8-(.. 

Jerry 
W3CDE 
Atlanta, GA 


-----Original Message----- 
From: Wendell Wyly W5FL [ mailto:wendell@wyly.org
<mailto:wendell@wyly.org> ] 
Sent: Sunday, September 08, 2002 9:21 PM 
To: Chris BONDE; Karl Kanalz 
Cc: antennas@mailman.qth.net 
Subject: RE: [Antennas] RE:Concrete To Use For Your Tower 


For non structural applications, fiberglass should do fine.  4 inch
slabs, 
small retaining walls, lightly loaded concrete tanks, etc.  Where there
will 
be thousands of pounds of tension, good old 5/8 and larger rebar will
remain 
king.  Concrete has very good compressive strength - hence the 3000 -
5000 
psi rating.  In tension it breaks very easily.  High strength concrete
is 
never made from a pea gravel (sack-crete) mix, rather using 1 to 1 1/2
inch 
rock in the mix to add tensile strength, when combined with rebar in the

areas of the concrete that will be put under tension, it is a very
strong 
structural member.  The rebar has ridges that prevent it pulling out and

does not depend on a good bond with the concrete mix, although if you
have 
ever taken a sledge and broken it off, it bonds better than you think. 

Don't wait to put up your tower for a replacement to re-bar. 

-- 



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