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Fibre Reinforced Concrete

There are many different types of fibre that can be used in concrete. From Fibre designed to lower the risk of plastic cracking to fibre that can be added as a replacement for welded wire mesh for crack control, or to increase flexural strength or of fire protection. The trick is to ensure you use the correct fibre for the required application.

 

Polypropylene (monofilament)

Typically used to reduce the instances of plastic cracking and to increase toughness in the concrete. Not recommended as a replacement for traditional shrinkage control reinforcement.

 

Polypropylene (fibrilated)

Typically used to reduce the instances of plastic cracking and to increase toughness in the concrete. Can be used as a replacement for traditional shrinkage control reinforcement in light applications.

 

High Performance Polypropylene (HPP)

Typically used as an alternative to traditional pavement reinforcement, increases flexural strength and toughness of the concrete. This fibre is non corrosive (wont rust).

 

Steel Fibre

Typically used as an alternative to traditional pavement reinforcement, increases flexural strength and toughness of the concrete. The highly alkaline properties of concrete protect the steel fibers from corroding. In a correctly placed and finished slab. The fibres will not protrude from the slab surface as the concrete wears, they will wear evenly with the concrete.

 

Typical Fibre reinforced concrete advantages

There are many advantages to fibre reinforcement when compared to traditional mesh reinforcement including;

 

- Fibre will be evenly distributed throughout the concrete, mesh (for crack control) should be positioned one third down from the top of the slab but often actually ends up to low (as concrete workers stand on the mesh) as there are typically insufficient bar chairs to maintain the mesh in position. Mesh is also often not tied together.

- Faster construction time, no time spent setting out mesh, tying sheets together, no time spent placing mesh on bar chairs. Generally saving some material costs but a lot of labour costs.

- Additional performance. Fibres often offer additional performance such as increased tensile strength, increased toughness and increased abrasion resistance.

- Protection against plastic shrinkage cracking in the early stages of finishing (and soon after before curing can commence)

Polypropylene fibre

HPP fibre

Steel fibre

Here are two typical commercial pavement pours, the left one contains traditional wire mesh, the right one has been reinforced with steel fibre, this has the additional advantage of allowing ready mix trucks onto the prep to discharge concrete without the need for a concrete pump as there is no mesh to be disrupted. It also reduces the risk of having the mesh positioned incorrectly in the slab.

Typical fibre types and their applications

Light residential where mesh might not be used but fibres may be considered for plastic shrinkage crack resistance

Residential driveways where light mesh might be specified

 

Light commercial where medium grade mesh might be specified

 

Fibre Type

Heavy commercial or industrial applications where heavy grade mesh might be specified

 

Cellulose

Polypropylene

High Performance Polypropylene

Steel fibre

 

Counties Ready Mix Ltd | Phone: 09 2946222 | Fax: 09 2946333 | email: info@crml.co.nz | PO Box 471, Drury, 2247

Physical address: 14 Bremner Road, Drury, Auckland, New Zealand | Google map link