Shotcrete concrete, also known as sprayed concrete, is delivered through a sealed, pressure-resistant hose and applied by spraying, which simultaneously compacts the concrete during placement. This method combines flexibility, efficiency and strong physical performance, making it ideal for complex or difficult-to-reach areas. Successful shotcrete concrete applications depend on the integration of advanced admixture technologies with modern materials handling systems. Sika’s shotcrete admixtures are developed to meet the increasing demands for performance, cost efficiency and worker safety, delivering reliable results in all site conditions.
Uses for Shotcrete
- Excavation stabilisation in tunnelling and mining
- Trench and slope stabilisation
- High performance linings
- Repair and refurbishment works
Concrete Requirements
- Adjusted workability (open time)
- Good pumpability
- Low rebound and dust formation
- Good adhesion to substrate
- Fast stiffening and early-strength evolution
- High durability
Advantages of Sika Admixtures for Shotcrete
- Enables concrete application without the need for formwork
- Adheres immediately, allowing application on any elevation or uneven substrate
- Provides excellent bond to the substrate for durable, stable performance
- Allows flexible control of layer thickness directly on site
- Suitable for both mesh and fibre-reinforced sprayed concrete
- Creates a rapid load-bearing surface with minimal waiting time
- Increases productivity through efficient, mechanised application
- Reduces rebound and material waste for more cost-effective construction
Sika Solutions for Shotcrete
| Sika® Sigunit® | Shotcrete accelerator for the highest strength development, ideal for overhead applications and building-up thicker layers. |
| SikaTard® | Cement hydration stabiliser to ensure long term stabilisation of the concrete mix, enabling optimum shotcrete application with the highest flexibility. |
| SikaFiber® | Fibres used to increase the resilience and energy absorption of the shotcrete. Highest performance with maximum efficiency. |
Our Range of Admixtures for Shotcrete
Sprayed Concrete Early Strength Classes
The lion's share of shotcrete is employed today in tunnel construction. Particularly here in deep mining, early strength development plays a central role. Shotcrete should be applied quickly in thick layers, including overhead. As a result the strengths of freshly-applied sprayed concrete are divided into three classes: J1, J2 and J3 (EN 14487).
Class J1 sprayed concrete is appropriate for application in thin layers on a dry substrate. No structural requirements are to be expected in this type of sprayed concrete during the first hours after application.
Class J2 sprayed concrete is used in applications where thicker layers have to be achieved within short time. This type of sprayed concrete can be applied overhead and is suitable even at difficult circumstances, e.g. in case of slight water afflux and immediate subsequent work steps like drilling and blasting.
Class J3 sprayed concrete is used in case of highly fragile rock or strong water afflux. Due to it’s rapid setting, more dust and rebound occurs during the application and therefore, class J3 sprayed concrete is only used in special cases.
