Effect of test specimen size on mechanical properties of shotcrete

Laboratory testing of shotcrete installed in the primary support system of the Sveti Ilija Tunnel is described in the paper. The effect of the size of shotcrete specimens on the compressive strength and dynamic modulus of elasticity of the plain concrete and fibre reinforced concrete produced in-situ is analysed. The results are used to analyse suitability of estimating compressive strength based on the dynamic modulus of elasticity results