Shotcrete (sprayed concrete) is an important material for supporting tunnels in hard rock. The rock surfaces exposed by blasting in the rock mass are usually covered with shotcrete immediately after scaling of loose rock has been carried out. With the compacting force from the impact against the rock, the shotcrete penetrates into cracks and cavities. This mortar effect, together with the stiffness of the shotcrete shell that bonds to the rock surface, helps to maintain and secure the tunnel’s arch shape from an early age. The safety of newly blasted tunnels, therefore, depends on the rapid hardening of the young shotcrete.
This study examines the early-age bond and compressive strength of wet-mix shotcrete with different SCM content, at low and high accelerator dosages.
The study was funded by BeFo and KTH and the engagement of the reference group consisting of Alf Nilsson, Karl-Martin Carlsson, Iad Saleh, Lars Olof Bryne, Anders Selander, Gustav Cederholm and Patrik Vidstrand is acknowledged.
