The physical and mechanical properties of prefabricated plaster materials prepared with large quantities of white slag as an aggregate replacement are studied in the form of plasterboards for use in construction. The initial characterization results show a reduction in the mechanical strength of the specimens as the amount of white slag increases, but the material maintains flexural values over 260 N with a 60% substitution of gypsum by white slag when a plasticizer additive is incorporated. The flexural values reach a level well above the 100 N needed per international standards. The thermal behavior at different doses of white slag is also studied with plasterboard specimens with dimensions of (300 × 400 × 15) mm. The heat transference coefficient by wall-air convection has values from 2.76 W/m2°C to 12.01 W/m2°C, which allows assessment of the thermal conductivity of these materials as a function of the amount of slag present in the mixtures. Non combustibility is discussed on the basis of experimental data obtained from two standard test methods: EN ISO 1716 with an oxygen bomb calorimeter and EN ISO 1182 with a cylindrical furnace. The fire response improves substantially as the slag byproduct from the steelmaking industry is incorporated compared to that of the behavior of the reference plaster, although there is a reduction in mass loss of up to 50%. This result could indicate an important advantage for these products for partitions or protection in areas with aggressive thermal requirements.
