Controlling Set Times during Gypsum Board Production with Retardan:

Gypsum boards are produced in a highly automated continuous process. Quick setting and hardening is of crucial importance to run the production at high speed for maximum capacity utilization. The use of calcined gypsum in combination with highly effective accelerator, especially fine ground gypsum, is currently state of the art. Consequently, the setting starts immediately after binder contact with water. On the other hand, beginning of setting needs to be delayed to enable an efficient mixing process and a homogeneous distribution of plaster slurry at the forming table. In our study, various commercially available retarders were tested for their efficiency and compatibility with numerous mix-design components. A new high-performance gypsum retarder, Retardan®-200 L, was found to set a new standard in retarding efficiency without demonstrating the known negative characteristics of existing technologies.

Innovative Additive Technologies for the Dry Mortar Industry with ViscoCrete:


Sika® ViscoCrete® Powder is a revolutionary concept to produce powdered superplasticizers that are extremely efficient at very low dosages. By using the Sika® ViscoCrete® range of powdered products it is possible to achieve a screed or mortar which is very easy and fast to pour and place. With Sika® ViscoCrete® Technology it is possible to achieve results once thought impossible with screeds and mortars. These properties and advantages have greatly helped to optimise the technical aspects of the screed and mortar production, the placing process, as well as improving the hardened screed and mortar appearance and properties.

  • Excellent flow, making thinner structures and smoother surfaces possible, even at low water-cement ratios
  • Low shrinkage and higher compressive strength resulting in less cracks and repairs
  • Improved finish around details and edges
  • Reduced permeability and increased chemical resistance


Application of a self-levelling screed
Self Levelling Screed:

Faster placing and less finishing work on site reducing the labour and equipment costs.

Application of a self-levelling underlayment
Anhydrite Screed:

Faster placing and less noise. Higher capacity when pumping through and improved flowability.

Hand applied Underlayment
Hand applied Underlayment:

The advanced rheological behavior enables very thin applications with extremely smooth surfaces.


Value Gain:
The outstanding properties of Sika® ViscoCrete® Technology result in considerable benefits for dry mortar and screed producers, contractors, specifiers and their clients. Millions of tons of screeds and mortars have now been produced on all continents with Sika® ViscoCrete® Technology. It has greatly helped to optimise both economical and technical aspects of the screed and mortar production and their application.

Improved production and placing processes:

  • Less additives needed
  • Reduced labour and equipment cost per unit

Improved quality and durability:

  • Fewer claims and rejects
  • Improved economy due to higher abrasion resistance

Improved health and safety conditions:

  • Formaldehyde-free formulation
  • Improved working conditions, due to less labour intensive application


Application of a non-shrinking grout
Non-Shrinking Grout:

Better consideration, resulting in higher strength and reduced bleed water.

Application of a tile adhesive
Tile Adhesives:

Improved rheology results in easier application and enhanced wetting properties.