Polypropylene Fibre Reinforcement in concrete 1

[hemis]

I am adding fibre reinforcement into slender beams which have no room for links (62mm by 125mm - 12mm reinforcement).

Does any one have information on the performance and behaviour of fibre-reinforcement please?

 

[ishvaaag]

Give a look at ACI Special Publication SP-138 Fiber-Reinforced-Plastic reinforcement for Concrete Structures International Symposium. Therein at page 619 you find equations to state the shear capacity.

 

[patprimmer]

creep or flow under long term load along with zero adhesion will be the problems with PP fibre reinforcment. I seem to remember somewhere that dog bone shaped or deformed fibres (maybe hammer milled) work better, but I do not have supporting data.

Aramid and glass fibre open weave fabrics have been tried in the past as well. I am unaware of their current status.

Regards
Pat
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[Ron]

Polypropylene fibers slightly enhance the properties of concrete, but do not provide reinforcement to replace steel. The enhancement they give to the concrete is the ability to resist "first crack" development, meaning that they tend to hold the concrete together a bit better while it gains strength, most particularly its tensile strength gain to resist shrinkage cracking.

For some information on the property enhancement of fiber addition to concrete, check publications of ACI Committee 544 on Fiber "Reinforced" Concrete. Please understand that fiber addition does not "reinforce" concrete in the classic sense of reinforcing steel, but does "reinforce" its properties to some degree.

 

[Qshake]

As Ron stated, the polypropolyene fibers are for control of crack and shrinkage and enhanced durability. They have no measurable effect on f'c that allows substitution of fibers for good old reinforcing steel.

Regards,
Qshake

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[hokie66]

Polypropylene fibres in concrete = sales spin.