ABSTRACT
Steel fibre reinforced shotcrete (sprayed concrete) is a vital factor for achieving long technical lifespan and safe performance for the support of hard rock tunnels. A large number of fibres must cross areas with large tensile stresses for the shotcrete to be efficient. Computed tomography (CT) is a laboratory testing technology based on X-ray scanning followed by digital image detection to visualize the material interior. This is here used in a mesoscale approach for investigation of in situ cored shotcrete samples containing full size fibres and aggregates. For investigating the occurrence and orientation of steel fibres in shotcrete this method is much more efficient than the traditionally used electron microscopy studies of sawn thin slices, which is time consuming, costly, destroys the samples and provide limited information. The newly developed method provide a complete and detailed description of the fibre orientation within a cored shotcrete sample.
