the three levels of fibre reinforcement
To help make it easier to select the correct fibre for your application and to dispel some of the mistruths claimed by some fibre manufacturers and suppliers, we have grouped the FRC fibres into 3 levels of increasing performance relative to the project type.
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Level 1 fibres are designed to reduce plastic shrinkage cracking in concrete in the first 24 hours after placing and finishing. Very fine monofilament fibres are used at a typical dosage of 0.6kg per cubic metre of concrete to reduce plastic shrinkage cracking prior to initial set. They are easy to add and mix and result in a near-invisible surface finish.
Recommended for concrete applications such as slabs-on-ground, overlays/toppings, curbs, driveways, foot paths, basement floors, garage floors, and coloured concrete – anywhere that the objective is to control plastic shrinkage cracking while improving basic durability properties. Requires no mix design or placement changes. Product Reference: FORTA Mighty-Mono® |
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Level 2 fibres are designed to reduce plastic and hardening shrinkage cracking in concrete and to act as an alternative reinforcing system to wire mesh in non-structural applications. Fibrillated, or net-shaped fibres are used at a typical dosage of 0.9kg per cubic metre of concrete to reduce plastic and hardening shrinkage. Recommended for use in quality concrete applications such as slabs-on ground, overlays/toppings, curbs, sloped paving, roads, driveways, footpaths, shotcrete, tilt-up panels, architectural/coloured concrete, precast, water tanks, and sewage treatment facilities – anywhere that peak fibre performance is desired and where the objective is to control temperature/shrinkage cracking while improving basic durability properties. Requires no mix design or placement changes.
Product Reference: FORTA Super-Net®/FORTA Econo-Cast® |
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Level 3 fibres represent the next generation of synthetic fibre technology and are capable of a much higher replacement level of conventional steel reinforcement. The FORTA FERRO® macro fibre system maximises each of the critical fibre characteristics that contribute to long-term durability and crack-control performance. Using advanced co-polymer chemistry, a blend of fibre shapes along with twisted bundles and special grey colour to assure uniform mixing and an excellent surface finish, this unique best-of-its-kind macrosynthetic fibre system may be used at much higher dosages (3.5kg, 4.5kg per cubic metre or more) without losing its user friendly reputation. FORTA FERRO® provides the highest slab curling reduction and post-crack performance values of any synthetic fibre in its class.
Product Reference: FORTA FERRO® |
which level of performance do i need?
The choice of fibre is dependent on a number of factors:
For Level 3 reinforcement, for warehouse slab on grade or similar projects, an engineered analysis of the project requirements is recommended and a resulting specification provided by Fibre Reinforced Concrete Ltd.
- The requirements of the project, for example a slab on ground:
- Is it a residential or industrial application
- What loads will the slab be subjected to? For example, cars or trucks?
- What joint spacing do I need or desire?
- The ability of the fibre chosen to be used in the concrete at the dosage required to perform
- Certification of the fibre to perform as claimed
- Cost - how much can the project afford vs. performance and dosage
For Level 3 reinforcement, for warehouse slab on grade or similar projects, an engineered analysis of the project requirements is recommended and a resulting specification provided by Fibre Reinforced Concrete Ltd.
Level 1 applications
Level one projects are where unreinforced concrete is typically used or a light-duty wire mesh provided for crack control. Level one fibres provide excellent plastic shrinkage crack control but offer little post-crack strength and therefore are not used in applications subjected to higher loading should the concrete crack.
Typical applications include:
Typical applications include:
- Footpaths, driveways, residential parking areas, bike paths, decorative concrete and any concrete where plastic shrinkage reduction is required, including steel reinforced concrete.
level 2 applications
Level two projects are similar to level one but the level two fibre offers a higher post crack strength and therefore more load carrying capacity should the concrete crack. Use in projects where the objective is to control temperature/shrinkage cracking while improving basic durability properties.
Typical applications include:
Typical applications include:
- All level one applications can use level two fibres.
- Driveways, commercial parking areas, larger slabs on grade, precast components, heavy duty concrete, shotcrete, etc can all use level two fibres.
LEVEL 3 APPLICATIONS
Level three projects are typically commercial and industrial type projects. These include:
Note that FORTA-FERRO® is a blended fibre system and includes a level two fibre to provide early-age plastic shrinkage crack reduction as well as the level 3 polymer fibre for high levels of post crack load carrying capacity.
- Warehouse slabs, storage unit slabs, heavy-duty parking and entrance ways, roads and accessways, precast tanks and wastewater projects, composite seel decks, shotcrete.
Note that FORTA-FERRO® is a blended fibre system and includes a level two fibre to provide early-age plastic shrinkage crack reduction as well as the level 3 polymer fibre for high levels of post crack load carrying capacity.