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Re: [TowerTalk] Rebar vs PVA Fibers for structural reinforcement

To: Rudy Bakalov <>
Subject: Re: [TowerTalk] Rebar vs PVA Fibers for structural reinforcement
From: David Gilbert <>
Date: Thu, 28 Aug 2008 15:46:52 -0700
List-post: <">>
It sounds like interesting stuff, and Nycon is a fine company ... I 
bought 40 lbs of their nylon fibers and had the stucco subcontractor add 
it to the scratch coat (first coat) when they coated my house since 
nylon holds its strength in high alkalai environments (like cement) 
better than standard glass fibers do. Nycon also makes steel fibers, and 
I think carbon threads. The PVA material is apparently a new product for 
them since I last dealt with them.

If the prices shown at the link below are any indication, though, I 
doubt you're going to want to use PVA fibers at 44 lbs per cubic yard to 
replace normal rebar. You're talking about a cost adder around $275 per 
yard (!) if I did the math right.

Aside from that, though, the following two quotes from the web page you 
referenced lead me to suspect that rigid structures like tower 
foundations may not be the intended application for this material. The 
suggested applications list situations where flexing is desirable, 
although I have to admit that a cast block of aluminum would probably 
still make an excellent tower base ;)

"This new class of materials produces a mortar that behaves like 
aluminum in flexural and tensile deformation."

"In tensile or flexural deformation, the material more closely resembles 
the ductility of aluminum."

You would probably also have a building code approval issue if you tried 
to rely on fibers only. In general, fibers are considered by the 
concrete industry to be only secondary reinforcement for the purpose of 
reducing cracks. Even the spec sheet on the nylon fibers I bought had a 
disclaimer for that, and steel rod reinforcement is generally required 
for structural applications. PVA fibers in the specified dosage might be 
equal or greater in strength (although apparently not in rigidity), but 
I'll bet it will take some time for the codes and inspectors to catch up.

Dave AB7E

Rudy Bakalov wrote:
> The specs for KURALON™ RECS15 state: "The optimum fiber dosage of PVA-ECC at 
> up to 44 lbs per cubic yard offers the possibility of reduced-steel and even 
> steel-free reinforcement."
>   Has anyone considered or even tried replacing rebar with PVA fibers?
>   Rudy N2WQ
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