Sustainable Materials Derived from Waste for Innovative Construction

This study investigates innovative, cement-free plaster mortars with enhanced thermal performance through the laboratory simulation of an in-situ casting process. One-part alkali-activated materials, in solid form and activated with water only, were employed to ensure process simplicity and sustainability. Industrial by-products (blast furnace slag, white slag, black slag) were used as precursors, and chemical–physical analyses assessed reaction products, porosity, and thermal behaviour. Two main formulations were developed: (i) a blast furnace slag-based system with different alkaline activators and aluminum powder as an expanding agent; (ii) a white slag-based system, able to react without external activators, combined with an alternative expanding agent. Results highlight the potential of these sustainable binders as innovative insulating mortars.