Using Reinforcing Fibres in Concrete
Concrete is usually reinforced using steel to prevent it from cracking and deforming under tensile strain. Reinforcing steel is effective at preventing large cracks from occurring in concrete however it is less effective at preventing micro-cracks. In situations where these micro-cracks need to be prevented, adding fibrous materials such as steel or micro-synthetic fibres in addition to reinforcing steel can improve concrete performance.
What properties can fibres effect?
Toughness
Impact resistance
Resistance to shrinkage cracking
Resistance to localised damage
Resistance to shear and torsion
Fatigue resistance
Spalling resistance when exposed to severe heat
Fibres are not a replacement to traditional reinforcing steel but, when used in addition to it, can increase the use cases for your concrete.
Picking the right fibre for the job
Different fibres achieve different results and it's important to pick a fibre that will achieve what you want it to. While Australian Standards don't provide for specific use cases for fibre in concrete, the Concrete Institute of Australia advises the following:
Steel Fibre Reinforcement: best used in flat slabs-on-grade subject to high loads and impact; shotcrete applications; tunnelling; slope stabilisation
Micro-Synthetic Fibre Reinforcement: slabs-on-grade, floor slabs and stay-in-placeforms in multi-storey buildings
Macro-Synthetic Fibre Reinforcement: situations which require high energy absorption post a crack occuring (require relatively large crack widths to be most effective)
Glass Fibre Reinforcement: used extensively in architectural cladding panels due to its light weight, affordability and ease of use
Want more information? Submit a quote request and we'll guide you through the process, including getting you specialised technical advice if you need it.
Other references:
https://www.concreteinstitute.com.au/getattachment/Resource-Centre/CIA-Library/Current-Practice-Notes/CPN-35---Fibres-in-Concrete/Fibres-in-Concrete.pdf.aspx
