For the widespread use of carbon concrete in construction, joining techniques are required to achieve a force-fit bond between prefabricated components. In addition to mechanical fasteners, such as dowels and bolts, epoxy resin adhesives and mineral-based mortar adhesives are primarily used for this purpose, with the latter representing a more sustainable alternative. A key challenge for existing systems lies in the non-destructive separation of the joints at the end of their service life. This paper addresses this issue and investigates the use of alternative cements as switchable adhesives for carbon concrete components. The corrosion resistance of carbon reinforcement enables new material combinations in this context that are not feasible in conventional reinforced concrete. For the first time, Sorel cement, a chloride-containing magnesia cement, is being investigated as a fast-setting mineral adhesive for carbon concrete. Furthermore, its selective dissolution in the adhesive joint under acidic conditions is tested—based on the “Debonding on Demand” principle. This paper describes the design of an adhesive based on Sorel cement in terms of workability, setting time, and solubility. Performance is validated through tensile adhesion tests, and finally, full joints between precast carbon concrete elements grouted with Sorel cement are tested in large-scale 4-point bending tests to assess the transferability to practical component dimensions.