Sika® Sigunit®-39 AF

Powdery alkali-free setting accelerator for shotcrete

Sika® Sigunit®-39 AF is an alkali-free setting accelerator for dry-mix shotcrete in powder form.

  • Alkalifree fast cement setting
  • Very economical and efficient
  • Lower rebound during application
Sika® Sigunit®-39 AF
Product Data Sheet Show all documents

Overview

Usage

Sika® Sigunit®-39 AF is especially formulated for use as setting accelerator in Portland cement based mortars and concrete. The product is particularly suitable for:
  • Applications, where high initial strength is needed and/or the shotcrete must play a supporting role in the early stage
  • Dry-mix shotcrete for tunnel repairs, heading stabilization in tunneling, slope and trench stabilization, etc.
  • Processing in thin-flow process
 

Advantages

The benefits of Sika® Sigunit®-39 AF include, but are not limited to the following:
  • Fast cement setting
  • High early strength development of shotcrete
  • Lower rebound during application
  • Improved bond of shotcrete to rock and concrete, making overhead spraying easier
  • Minimum strength loss in the accelerated concrete
  • Sika® Sigunit®-39 AF is non corrosive to steel reinforcement
  • Alkali-free, which eliminates any adverse effects from additional alkali in the spray dust
  • No additional surface and ground water pollution by leached-out alkali

Packaging

25 kg bags, 40 bags on a palett

1000 kg big-bag

Colour

White powder

Product Details

CERTIFICATES AND TEST REPORTS

Confirms to EN 934-5, Table 2 (Non-alkaline sprayed concrete accelerator)

Composition

Mineral based, alkali-free

Shelf life

24 months shelf life from date of production if stored properly in undamaged, unopened, original sealed packaging.

Storage conditions

Dry storage at temperatures up to 30 °C. Protect from direct sunlight.

Bulk density

0.80 ± 0.1 g/cm3

pH-Value

3.5 ± 0.5 at +23 °C (100g/l H2O)

Total chloride ion content

≤ 0.1 %

Equivalent sodium oxide

≤ 1.0 %

 

Specific advice

The acceleration effect is dependent on the cement (content, type and age), the shotcrete and substrate temperatures, layer thicknesses and the spray process. In dry spraying, the quantity of mixing water is an important criteria, also relevant for the accelerating effects of Sika® Sigunit®-39 AF.
When applying shotcrete in thicker layers, make sure that the temperature of the basic concrete is not below +15 °C. Lower temperatures require a higher dosage of the accelerator.

Clean all tools and application equipment with water immediately after use.

Application

Compatibility

Sika® Sigunit®-39 AF may be combined with Sika® ViscoCrete® Powders for water reduction.

Important: Always conduct trials before combining products in specific mix designs and contact Technical Services Department for any additional information and advice concerning specific combinations with other products.

Dispensing

Sika® Sigunit®-39 AF is added to the dry mix in the drymix mortar plant. Alternatively, it can be added to the dry mortar/concrete premix at the construction site prior to feeding the spray equipment (rotor machine).

Recommended dosage

Typical dosage in the range of 2 to 6 % of the binder weight. The maximum dosage should not exceed 6 % of the binder weight. The water-binder ratio should be below 0,5 to ensure durability and ultimate strength reqired. The addition of water-reducing additives (Sika ViscoCrete Powder) is recommended.

Note: Preliminary testing is required to determine the exact dosage for your specific conditions. Please contact our Technical Services Department for more information and advice.

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