Can structural plastic fibres reduce reinforcement in precast?

[Scott200577]

Hi all!
Am a 27 year old engineer with a major precast firm in the uk.We are currently looking at ways of reducing the need for steel reinforcement in our products by use of structural plastic fibres. Unfortunately I have next to no experience in this field and was therefore looking for a few pointers if possible? From where I'm standing at the moment it looks like the main areas would be in crack control at corners, possibly in our retaining walls and crash barriers-is this a reasonable assumption?
Can structural plastic fibres also reduce the nead for shear reinforcement - presumably if so this would depend upon alignment?

Any help would be gratefully appreciated!

Thanks!

 

[SlideRuleEra]

Fibers are often considered as either an altenative to welded wire fabric OR as a supplement to structural reinforcement - but not a replacement for reinforcing steel. Here are some links for general information:
ftp://imgs.ebuild.com/woc/C00I048.pdf
ftp://imgs.ebuild.com/woc/C99J043.pdf
ftp://imgs.ebuild.com/woc/C960537.pdf

 

[Ron]

Fiber in concrete is a material enhancement, not a reinforcement. The only gain you get with respect to reducing reinforcement is that the properties of the concrete can become better with fiber addition, though for structural applications, I would look to steel fiber, not polypropylene fiber.

The way it works is that when you add fiber, you increase the strength properties of concrete and provide more resistance to bending and shear. The amount and type of fiber will dictate the actual properties. In that context, you might reduce your computed reinforcement slightly because of the increase in concrete strength properties, but there is not a one-for-one replacement scheme substituting fiber for rebar.