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SikaFiber®-12-34

Special polypropylene fibre for concrete and gunite

SikaFiber®-12-34 is a high quality, 100% virgin, monofilament polypropylene fibre, coated with a surfactant to improve initial dispersion and bond with the cement paste, designed for the prevention of concrete spalling in the event of fire. It also reduces the occurrence of plastic shrinkage and plastic settlement cracking whilst enhancing the surface properties and durability of a cementitious matrix. Suitable for use in hot and tropical climatic condition

  • Helps maintain the integrity of the whole structure in the event of fire
  • Reduces future repair costs
  • Provides passive fire protection to both shotcrete and cast concrete and an extremely cost effective solution when compared to alternatives such as sprayed coatings or barrier methods
  • Beyond enhancing spalling resistance, addition of polypropylene fibres to wet shotcrete improves the ability to apply greater thicknesses in a single pass, reduces rebound, enhances early age crack control, reduces line pressure in spray pumps and may reduce the dosage of set accelerator
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Usage

SikaFiber®-12-34 is used to prevent concrete spalling (breaking off of layers or pieces of concrete from the surface of a structural element when exposed to the high and rapidly increasing temperatures experienced in fires), mainly in underground structures. In the event of a fire, as the temperature of the concrete increases, the moisture in the concrete becomes steam. If this steam is unable to escape an increase in pressure inside the concrete builds up to the point where it exceeds the tensile capacity of the concrete causing pieces of concrete to be violently and explosively dislodged. The addition of suitable polypropylene fibres in cast concrete has been accepted to counteract explosive spalling. The fibres melt inside the concrete creating the necessary voids for the steam to escape thereby preventing spalling and so maintaining the integrity of the structural element.
  • Concrete, mainly when HPC and low permeability concrete is specified because of the greater pore pressures that build up during heating
  • Precast concrete tunnel segments
  • Concrete submitted to very high temperatures
 

Advantages

  • Helps maintain the integrity of the whole structure in the event of fire
  • Reduces future repair costs
  • Provides passive fire protection to both shotcrete and cast concrete and an extremely cost effective solution when compared to alternatives such as sprayed coatings or barrier methods
  • Beyond enhancing spalling resistance, addition of polypropylene fibres to wet shotcrete improves the ability to apply greater thicknesses in a single pass, reduces rebound, enhances early age crack control, reduces line pressure in spray pumps and may reduce the dosage of set accelerator

Packaging

0.6 kg, 0.9 kg and 1 kg in water soluble bags and 450 kg jumbo bag

Colour

White fibre

Product Details

Sustainability / Certifications / Approvals

APPROVALS / CERTIFICATES

Complies with EN 14889-2: Polymer Fibres - Definitions, Specifications and Conformity; Class 1a

 
Product Information

Composition

Polypropylene

Shelf life

24 months from date of production if stored properly

Storage conditions

Store in undamaged, unopened, original sealed packaging in dry conditions at temperatures between +5 °C and +45 °C. Protect from direct sunlight, moisture and frost.

Density

~0.91 kg/l (+25 °C)

Dimensions

Length

~12 mm

Diameter

~34 µm

Melting point

~160 °C
Technical Information

Concreting guidance

The standard rules of good concreting practice for production and placing must be observed when using SikaFiber®-12-34 in concrete. Refer to relevant standards.
Fresh concrete must be cured properly especially at high temperatures in order to prevent plastic and drying shrinkage. Use Sika® Antisol® products as a curing agent.

Resistance to alkalinity

Excellent

Application

Application Information

Compatibility

SikaFiber®-12-34 may be combined with all types of Portland cement, concretes containing pozzolanic materials such as; GGBS, PFA , micro-silica and the following Sika product ranges:

  • Sika® ViscoCrete®
  • SikaPlast®
  • Sikament®
  • Plastiment®
  • Sika Aer®

We recommend to perform trial mixes to establish the required performance when combining SikaFiber®-12-34 with the above or other admixtures. Please consult our Sika Technical Department.

Dispensing

Plant mixing:

SikaFiber®-12-34 should be added to the mixer after all other ingredients and water. Use a mixing time that ensures uniform dispersion of the fibre.

Truck mixing:

SikaFiber®-12-34 is best added in the batching plant mixer; although in cases where this may not be possible addition in the truck can be done. The fibre should be added first with ~30 % of the mixing water. Add the other ingredients, the remaining mixing water and continue mixing for a further few minutes at full speed to ensure uniform dispersion of the fibre.
Consumption

Recommended dosage

SikaFiber®-12-34 is supplied ready to use.

The accurate determination of the minimum fibre dosage to provide explosive spalling resistance can only be established by large scale fire testing of the concrete to be used on a specific project.

Section 6.1 of the European Standard EN 1992 Eurocode 2 makes reference to the use of 2 kg/m3 of polypropylene fibres to control explosive spalling in high strength concrete. This dosage provides a very good safety margin, but does not preclude the use of lower dosages if fire testing on large concrete samples has been carried out. Dosage rates of 1.5 kg/m3 or less have been used after accurate trials.

We recommend to perform trial mixes to establish the required performance. Please consult our Sika Technical Department for further assistance.

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