Concrete Concrete Admixture Shotcrete Article

Successful sprayed concrete requires the combination of many aspects of modern concrete technology especially concrete admixture chemistry, together with modern materials handling technology. The increasing demands for cost-effectiveness and the protection of health and the environment mean that sprayed concrete has been in continuous development. Thanks to more than one hundred years of experience, expert knowledge and a focus on performance and economy, Sika is able to provide the newest generation of sprayed concrete solutions.

Sprayed Concrete Has Many Advantages

  • Application to any elevations because sprayed concrete adheres immediately and bears its own weight
  • Can be applied on uneven substrates
  • Good adhesion to the substrate
  • Totally flexible configuration of the layer thickness on site
  • Concreting without formwork
  • Reinforced sprayed concrete is also possible (mesh/fiber reinforcement)
  • Rapid load-bearing skin can be achieved without forms or long waiting times
Sika Aliva machine spraying concrete shotcrete

Sprayed Concrete Applications

Sprayed concrete has a wide application range due to its high flexibility, good economics and good physical properties. However, the sprayed concrete method is requiring a high degree of mechanization and well trained nozzle operators. Nevertheless, the advantage over conventional concreting methods is outstanding: the application of concrete without any formwork. Sprayed concrete is mainly used in the following applications:

  • Excavation stabilization in tunneling and mining construction
  • Slope and trenching stabilization
  • Protective lining
  • Concrete repair (concrete replacement and strengthening)
  • Special lightweight load-bearing structures
  • Restoration of historic buildings (stone structures)
  • Sealing works
  • Construction of swimming pools

Requirements for Sprayed Concrete

The multiple demands placed on sprayed concrete today no longer allow standard solutions. Dependent on the spray process and the type of structure, different conditions are imposed on the sprayed concrete during application and in service.

In tunnel construction sprayed concrete is normally used for excavation stabilization, in open-pit mining and on major construction sites it is typically used for rock and soil stabilization on slopes. In bridge and other civil engineering repair and refurbishment works, sprayed concrete is often used specifically because formwork can thereby be dispensed with.

Shotcrete with Sigunit accelerator to strengthen underground structures of mine

Sika Solutions for Sprayed Concrete

Sika’s products for sprayed concrete represent the newest generation and cutting-edge technologies that have resulted from more than one hundred years of involvement in the business. With this experience, expert knowledge and a focus on performance and economy, Sika provides reliable proven solutions.

Sika is the expert in all the available technologies for sprayed concrete, including both the wet and the dry spray processes. This allows us to provide the optimum solution for each type of project and application, including the development of our own sprayed concrete machines at Aliva® AG. When combined with our research, development and globalized production of specialist sprayed concrete admixtures, such as Sika® Sigunit® and Sika® ViscoCrete®, plus our years of experience in tunneling, mining and on all types of major construction projects, this makes Sika the ideal partner for owners, designers and contractors on any type of sprayed concrete works.


Sika® Sigunit® Shotcrete accelerators, available as liquid, powder or instant powder, for the highest strength development, ideal for overhead applications and building-up thicker layers.
Sika® ViscoCrete® SC High range water reducing superplasticizers for better workability of the concrete mix, higher compressive strength and increased durability of the shotcrete.
SikaTard® Cement hydration stabilizer to ensure long term stabilization of the concrete mix, enabling optimum shotcrete application with the highest flexibility - Always just in time.
SikaPump® Pumping aids improve the pumpability of the concrete mix. For a smooth pumping process over long distances and time, with minimal friction and wear on the equipment.
SikaTell® Colloidal silica additive for stabilizing the concrete mix cohesion and thereby reducing rebound and improving the long-term durability of the shotcrete.
SikaFiber® Steel or synthetic fibers used to increase the resilience and energy absorption of the shotcrete. Highest performance with maximum efficiency.
SikaFume® Micro silica additives that significantly improves the shotcrete and its durability: Optimum adhesion and minimal rebound, followed by watertight durability.
FlexoDrain Substrate drainage system installed to allow the shotcrete application in case of moderate water ingress and protecting the lining from aggressive mountain water.

Specialist equipment for all types of wet and dry process shotcrete application and accelerator dosing. Off-the-shelf and tailor-made solutions.

SikaCare Reduces the adhesion of cement mortar and concrete to the equipment, allowing extended use, lower wear and easier cleaning after the application.
SikaPump®-Start 1 Lubricant for concrete pumps, significantly reducing the friction between concrete and hoses/pipes, during the start-up of the pumping process.
SikaShot® Highly accelerated spray mortar for consolidating and pre-sealing the substrate. Ideal pretreatment under difficult conditions for the optimum shotcrete lining.