ABSTRACT
Fibre-reinforced shotcrete (sprayed concrete) is a major component in the support system for tunnels in hard rock. Large volumes of shotcrete used to support tunnels generates high CO2-footprints which must be reduced to decelerate the continuously increasing emissions of greenhouse gases. The need for reducing the environmental impact of tunnel construction today, therefore, puts focus on finding alternatives, including the use of different types and materials for fibres for use in shotcrete. Shotcrete with fibres of steel, basalt and synthetic materials of typical geometries have been tested and compared at various dosages. A tendency is that steel and basalt fibres perform better at small displacements, and synthetic fibres are better at large displacements. The goal is to identify several shotcrete mixes suitable for use in tunnelling so that the right material and fibre volume can be used in the right place.
