The results from an extensive shotcrete failure mapping together with initial adhesion strength tests showed that there were a number of parameters for unreinforced shotcrete as rock support that needed to be further investigated. A more extensive adhesion strength test program was carried out which included studying the effects of accelerator concentration, time and the surface treatment method. The results from these investigations are presented in this paper. It is shown that water-jet scaling and sufficient thickness of the shotcrete give favourable conditions for the use of unreinforced shotcrete as rock support. The result of the tests carried out in Kiirunavaara shows that the adhesion strength has a wide range of variation.