Development of Sustainable Gypsum Composites Incorporating Silica Fume Waste and Fiber Reinforcement for Construction Applications

This study evaluates the feasibility of developing sustainable gypsum composites incorporating silica fume waste and fiber reinforcement for construction applications. The experimental program was divided into two phases. First, silica fume was incorporated into the gypsum matrix at addition levels ranging from 10% to 35% by weight of gypsum using water-to-gypsum ratios of 0.7 and 0.8. Dry bulk density, Shore C hardness, flexural strength, and compressive strength were determined according to standards. Subsequently, the most promising formulations were reinforced with polypropylene and glass fibers at dosages of 2% and 4% by weight of gypsum. Selected specimens were also analyzed by scanning electron microscopy (SEM). The results showed that silica fume can be successfully incorporated at levels of up to 35% while complying with the requirements established by UNE-EN 13279. Silica fume addition increased bulk density by up to 9.64% and improved surface hardness. Fiber reinforcement further enhanced mechanical performance, with the best formulation reaching compressive strength values close to 14 MPa, representing an increase of 27.14% compared with the corresponding silica-fume matrix. SEM observations confirmed matrix densification and satisfactory fiber–matrix adhesion. These findings demonstrate that the combined use of silica fume waste and fiber reinforcement is a viable strategy for producing gypsum composites with improved performance while promoting industrial waste valorization.