IN THE MIX - THE LATEST CONCRETE NEWS

FIBRES IN CONCRETE – WHAT, WHEN & WHY? 15 May 2013

CCANZ Information Bulletin 39 Fibre Reinforced Concrete is an excellent resource for those wishing to address confusion around the appropriate use of fibres in concrete.

IB 39 Fibre Reinforced Concrete outlines:

  • The different types of fibre commonly available on the New Zealand market
  • How fibres can be used to enhance the properties of concrete
  • The properties of concrete made using fibres
  • The manufacture and testing of fibre reinforced concrete (FRC)
  • Typical applications of FRC

The use of fibres to reinforce and enhance the properties of construction materials goes back at least 3,500 years, when straw was used to reinforce sun-baked bricks in Mesopotamia.

Cement-bound products have been reinforced by various types of fibre at least since the beginning of the last century, and steel and synthetic fibres have been used to improve the properties of concrete for the past 30 or 40 years.

Fibres also improve the properties of many natural as well as engineered materials, e.g. motor vehicle tyres are made from fibre reinforced rubber.

IB 39 takes a look at the use of discontinuous fibres in conventionally mixed concrete, but not in cement.

In other words, it focuses on fibres added during the batching and mixing of concrete but excludes, for example, glass fibre reinforced cement (or concrete) – GRC, asbestos cement, and other specialised materials such as ultra-high performance fibre reinforced (or ‘ductile’) concrete.

Some synthetic fibres not commonly used in New Zealand, e.g. aramid, carbon, polyester, are also excluded.

In compiling IB 39 CCANZ sought input from a range of parties interested in advancing the use of fibre reinforced concrete in New Zealand. This included fibre manufacturers and suppliers, design engineers, testing professionals, and concrete engineers and specialists.

While every effort has been made to ensure accuracy, it was not possible to verify all claims made relating to proprietary or specialist products. As such, IB 39 seeks to provide generic information arrived at through consensus.

Users of IB 39 should seek independent verification or test results to satisfy themselves that their own specific requirements will be met in areas such as fibre type, fibre dosage, concrete properties, crack control, joint spacing and fire resistance.

It must always be remembered that no two fibres are the same and that comparisons of performance should only be made on a particular concrete dosed with a specific mass or volume of a particular fibre against a specific mass or volume of a different fibre used in the same concrete.

Download IB 39 Fibre Reinforced Concrete from the CCANZ website.

Taken from the April 2013 NZRMCA Newsletter