[TowerTalk] concrete

[Artmouton]

Thanks for the info.  That is why I joined the list.
Art K5FNQ

----- Original Message ----- 
From: "David Gilbert" <xdavid at cis-broadband.com>
To: "Artmouton" <k5fnq at cox.net>
Cc: "towertalk" <towertalk at contesting.com>; "Its from Onion" 
<aredandgold at msn.com>
Sent: Monday, December 31, 2007 11:40 AM
Subject: Re: [TowerTalk] concrete


>
>
> Even the manufacturers of various fibers (glass, nylon, polypropylene,
> steel, kevlar, spun carbon ... in approximate order of strength and
> cost) refer to them as "secondary reinforcement" and specifically state
> that they are not a substitute for rebar for structural strength.  They
> add localized strength and help to avoid small cracks, but will not hold
> a mass of concrete together like rebar will.  NEVER leave out a proper
> rebar skeleton ... concrete is fantastic in compression but totally
> unreliable in tension by itself.
>
> By the way, the fibers you get from a typical concrete supplier are
> usually just some version of spun glass.  They are inexpensive and help
> to avoid small cracks as the concrete cures, but are almost worthless
> for longer term strength since the alkali in the concrete attacks the
> glass.  I've seen figures indicating that about 80% of the strength of
> simple glass fibers is gone after 30 days.  I went with glass fibers
> when I had the slab poured for this house because I laid down LOTS of
> rebar first and I was unable to talk the concrete supplier into using
> any other type of fiber anyway, but when I contracted to have stucco
> applied to the outside of the house I supplied my own nylon fibers to be
> added to each mixer batch.  I bought the fibers from www.nycon.com, but
> they also sell steel fibers if anyone really wants to beef up their
> tower foundation ... or improve their UFER ground ;)
>
> 73,
> Dave   AB7E
>
>
>
> Artmouton wrote:
>> Or Rebar - or will both be best?
>> Art K5FNQ
>> (about ready to put base in for Rohn 55)
>>
>>
>> ----- Original Message ----- 
>> From: "Its from Onion" <aredandgold at msn.com>
>> To: "towertalk" <towertalk at contesting.com>
>> Sent: Sunday, December 30, 2007 7:48 PM
>> Subject: [TowerTalk] concrete
>>
>>
>>
>>> Don't forget the use of fiber in the concrete mix.
>>>
>>> Lee
>>> KE4VYN
>>> _______________________________________________
>>>
>>>
>>>
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