Fiber reinforced concrete replace wire mesh? 3

• Nov 30, 2006

• #2

henri2

Materials

Jul 20, 2005

512

At the top of the page, you can search for what you want in eng-tips. Type in "fibermesh" and proceed from there. There are numerous posts regarding this subject.

 

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• Nov 30, 2006

• #3

SperlingPE

Structural

Dec 27, 2002

591

Fibermesh is for crack control only. If wire mesh is needed as bending reinforcement (for strength), the fiber mesh is not a substitute.

 

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• Nov 30, 2006

1
• #4

miecz

Structural

Sep 30, 2004

1,400

See thread507-144777.

 

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• Nov 30, 2006

• #5

Qshake

Structural

Jul 12, 2000

2,672

Fibers generally in low volumes are for crack control (dry shrinkage and temperature), however, large volumes of fibers - 0.5% can be used for strength.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

 

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• Nov 30, 2006

• #6

Taro

Structural

Nov 29, 2000

713

Qshake, are there any building code evaluation reports that approve fibers for replacing structural rebar? The ones I have seen explicitly state that this is not allowed.

 

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• Nov 30, 2006

• #7

miecz

Structural

Sep 30, 2004

1,400

I'm still confused as to the benefits/uses of fibermesh, which is why I don't use it. I was under the impression that the major benefit of fibermesh was to control plastic shrinkage cracking, and that it had little effect on temperature shrinkage or strength. Is there an ACI publication that recommends design minimums for fiber reinforcing, to be used in lieu of Chapters 7 and 10 of ACI 318?

 

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• Nov 30, 2006

• #8

COEngineeer

Structural

Sep 30, 2006

1,186

I just thought you use fibermesh to increase your fc. It has nothing to do with reinforcement.

 

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• Nov 30, 2006

• #9

twinnell

Structural

Jan 20, 2005

212

Synthetic fiber reinforcing is not used to increase the compressive strenght of concrete.

Go to

http://www.fibermesh.com

for more information.

 

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• Nov 30, 2006

• #10

mbullism

Structural

May 8, 2006

80

ACI 302.1R-96 "Guide for Concrete Floor and Slab Construction", Section 5.8 "Reinforcement", Section 5.8.3 "Synthetic Fibers":

"Synthetic fibers are used in floors to minimize plastic shrinkage cracking of concrete. These fibers should not be used to replace temperature and shrinkage reinforcement because they have little impact on the behavior of concrete after it hardens."

 

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• Nov 30, 2006

1
• #11

WillisV

Structural

Apr 24, 2005

1,352

Please see my response at the bottom of this thread: thread507-156960

 

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• Nov 30, 2006

• #12

Qshake

Structural

Jul 12, 2000

2,672

My apologies....I don't think there are any codes that allow full replacement or 1:1 replacement. I didn't intend to mean or imply a full replacement. But ACI 544 and related documents present the mechanics on FRC such that less conventional reinforcing can be used.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

 

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• Nov 30, 2006

• #13

dik

Structural

Apr 13, 2001

25,751

jmiec: polypropylene fibres retard the release of bleed water and in the process provide a more uniform initial hydration. This better disburses microcracking and hence improves shrinkage cracking... as I understand.

Dik

 

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• Nov 30, 2006

• #14

SlideRuleEra

Structural

Jun 2, 2003

5,528

mathewbaker - The Steel Deck Institute (SDI) allows steel fibers to be used instead of WWF for temperature & shrinkage reinforcement of composite metal decks. There is (at least) one product that is a BLEND of steel fibers and synthetic fibers that meets the SDI requirements. See this link

http://www.fibermesh.com/downloads/Composite Metal Decks.pdf

http://www.SlideRuleEra.net

 

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• Nov 30, 2006

• #15

miecz

Structural

Sep 30, 2004

1,400

dik-

I believe what you're referring to (and referred to in mbullism's post)is called "plastic shrinkage cracking" that occurs during the curing process, as opposed to shrinkage that occurs over months or years.

Aren't proper curing techniques supposed to prevent plastic shrinkage cracks?

 

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• Dec 1, 2006

• #16

MALKOBANI

Structural

Oct 16, 2006

21

Bekaert has steel fiber products ,Dramix, Wiremix and DramixDuo that replace the traditional WWM. They also have a free computer program called DRAMIX DRAPRO that designs the slab for different types of loading.

 

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• Dec 1, 2006

• #17

dik

Structural

Apr 13, 2001

25,751

jmiec: yes, but the PP fibres improve on this. Little can be done for the long term shrinkage, except for a 'contained plastic flow' for lower strength concretes. Over a period of time, lower strength concretes (<4500psi)exhibit a better plastic behaviour than elastic. Higher strength concretes behave more elastically and more brittle.

Dik

 

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• Dec 1, 2006

• #18

jike

Structural

Oct 9, 2000

2,160

It is my understanding that fibers cannot be used to replace flexural steel required for negative moment over beams or girders. The composite deck acts as the positive moment steel. The fibers or WWF is for shrinkage and temperature only.

 

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• Dec 1, 2006

• #19

miecz

Structural

Sep 30, 2004

1,400

I'd like to see this question put on a multiple choice test.

Choose the statement that you most closely agree with:

A. fibers are worthless
B. fibers help prevent plastic shrinkage cracking
C. fibers prevent long term shrinkage cracking
D. fibers prevent cracking due to temperature effects
E. fibers can be used to structurally reinforce concrete
F. fiber design is covered by the concrete institute
G. fiber design is covered by the metal deck institute
H. fibers increase the compressive strength of concrete

Apparently, I'm not the only one who is confused, and I think I know who is causing the confusion.

 

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• Dec 1, 2006

• #20

dik

Structural

Apr 13, 2001

25,751

B & D for a start... Dik

 

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