Permanent modern shotcrete support in hard rock conditions is commonly based on achieving sufï¬cient bond strength to the rock. A system with reinforced shotcrete with mesh reinforcement or ï¬bers is dependent on the bond strength being able to carry loads from loose blocks. This is especially important where no, or very few, rock bolts are installed. Investi-gations1 show this behavior clearly. In Sweden, a common requirement for the bond strength between shotcrete and rock is a minimum of 73 psi (0.5 MPa). It is also essential to have full interaction between different shotcrete layers with a bond level of at least 145 psi (1.0 MPa). Also, in the repair of old concrete structures, Swedish bond strength requirements for the interaction between old concrete and new shotcrete are at least 218 psi (1.5 MPa).