Today, the world is facing an enormous challenge where the emissions of greenhouse gases mustbe reduced significantly to stop the increasing mean temperature. For the construction industry,this challenge means that structures must be designed more carefully, and materials must be usedand produced more efficiently. Concrete is one of the most widely used materials, and cementproduction alone contributes to around 8 % of the world's total CO2 emissions. This paper presentsa pilot study in which part of the cement clinker content in accelerated shotcrete is replaced withground granulated blast furnace slag (GGBS). Shotcrete is widely used as part of the rock supportfor tunnels in hard rock and has a large cement content. Thus, the environmental impact must bereduced significantly to meet future demands. However, introducing GGBS will slow downstrength development, which is a crucial part of shotcrete. Thus, this paper aims to investigate theearly strength development, i.e., after one and seven days. The results show that an averagecompressive strength of 18 MPa can be reached after 24 hours when 35 % of the cement clinkercontent is replaced with GGBS. Finally, some important topics for further studies are pointed out.