Testing of sprayed waterproofing membranes for single shell sprayed concrete tunnel linings in hard rock

Tunnel linings based on sprayed concrete and sprayed waterproofing membranes are being considered for rail and road tunnels in hard rock in Norway. One completed tunnel and several specially constructed test sections with this tunnel lining type have been sampled and investigated in order to determine the in-situ condition of the tunnel lining. Results from these investigations show high humidity contents in the sprayed concrete material. The measured humidity contents in the membrane material are consistently much lower than the measured concrete humidities would suggest. Based on fissure recordings in sprayed concrete linings, measured thermal expansion, design aerodynamic loads and expected bond between the rock and sprayed concrete an assessment of the function and loading scenarios for the tunnel lining is done. A program for the testing of membranes with the goal of accepting membrane products is proposed on this basis. Preliminary results from these tests show significant performance differences for different membrane products.