Mechanical Performance and Environmental Assessment of Hybrid Reinforced Gypsum Composites Incorporating Commercial and Recycled Fibers

The use of hybrid fiber reinforcement has been investigated to enhance the performance of gypsum-based materials, taking advantage of several types of fibers. This study develops hybrid fiber-reinforced gypsum composites (HFRGCs) incorporating sixteen combinations of recycled mineral wool (RMW) and polypropylene (PP) fibers, with contents ranging from 0.25 to 1.00 wt.%. The samples are mechanically characterized, and statistical analyses of the measured values are conducted. Moreover, a life cycle assessment (LCA) is also performed regarding their environmental impacts. The HFRGC containing 0.50 wt.% RMW fibers and 1.00 wt.% PP fibers exhibited the highest surface hardness, with a 5.5% increase compared with the reference. The highest flexural and compressive strengths were achieved by HFRGCs containing 0.50 wt.% PP fibers, reaching increases of 7.5% and 9.0%, respectively, with only a minor influence of RMW fibers, whose greatest contribution was reducing environmental impacts due to the low energy demand for recycling this industrial waste compared with the high emissions from PP fiber production. A statistical analysis revealed no significant differences in the mechanical properties of HFRGCs containing 0.50 and 1.00 wt.% PP fibers, suggesting that increasing the PP fiber content beyond 0.50 wt.% did not result in significant mechanical improvements. Therefore, considering both mechanical and environmental aspects, the HFRGC incorporating 1.00 wt.% RMW fiber and 0.50 wt.% PP fibers provided the most balanced overall performance.