Valorization of Recycled Gypsum from CDW in Green Binder Systems

The circular economy in construction requires the valorization of gypsum waste from construction and demolition. Waste from gypsum plasterboards is considerable, yet it is still viewed more as a problem than as a mineral resource. This study investigates the potential for utilizing recycled gypsum (RG) from waste plasterboards in the production of blended green binders. Four gypsum-cement-pozzolanic binders are designed with two pozzolanic additives (natural zeolite and recycled brick powder) in two ratios to cement-0.6 and 1.0. The structural mineral compounds of the binders are analyzed by XRD and DTA/TG, while the performance of both fresh and hardened paste is evaluated by standardized methods for binders to determine possible construction applications of these green binders. Results show that RG can be used to produce blended fast-setting binders with a gypsum content of above 40%. Systems with natural zeolite achieve higher strength (up to 30 MPa at 90 days) and sufficient water resistance, thus suitable even as substitutes for cement binders. The developed blended binders with recycled brick powder can be used in low-moisture environments only as substitutes for gypsum binders in plasters, masonry units, and lightweight composites.