Shotcrete is a placement method for concrete. Concrete mixtures that have been shotcreted have used all different supplemental cementitious materials (SCM) including slag. Silica fume, and fly ash are also widely used. Generally geographic availability and cost of the slag are a deciding factor on if slag is included in a concrete mixture design. Concrete using alternative binders or cements have been used for specialized applications like refractory, or extremely high early strength gain. Here are links to past articles from our Shotcrete magazine that have considered slag in shotcreted concrete mixtures:

The Use of Slag Cement, Alkali-Free Accelerator, and Macro-Synthetic Fibers uploads/2020/05/2016Spr_Yurdakul-etal.pdf

Sustainable Shotcrete Using Blast-Furnace Slag content/uploads/2020/05/2013Fal_Sustainability.pdf