ABSTRACT
Lack of knowledge regarding the effectiveness of steel fibres in shotcrete (sprayed concrete) today often leads to over-dimensioning the thickness of shotcrete in tunnels. With a more optimal use of steel fibres in shotcrete, a reduced number of ineffective fibres leads to a reduced consumption of steel, concrete and cement. A tomography-based method with a special analysis routine has been developed for investigation of shotcrete cylinder samples. The method reports the position and 3D orientation of steel fibres, described with two inclination angles and as the number of fibres situated over the shotcrete thickness. A module that calculates the corresponding load carrying capacity in flexure for the investigated shotcrete samples have now been added. The combined method was used within a study that show a representative variation of steel fibre orientation in shotcrete for normally occurring material compositions and tunnel conditions.
