Synergistic Effects of Hollow Glass Microspheres and Sisal Fibers in Natural Gypsum-Based Composites: Achieving Lightweight, High-Strength, and Aesthetically Superior Construction Materials

This study explores the synergistic development of natural gypsum-based composites (NGBCs) with enhanced multifunctional characteristics, employing hollow glass microspheres (HGMs) as density-reducing agents and sisal fibers (SFs) as mechanical reinforcement phases while maintaining superior whiteness properties. Five HGM variants with precisely graded particle sizes (20, 40, 60, 80, and 100 μm) were systematically incorporated into the composite matrix. Sisal fibers with controlled length parameters (10–15 mm) were uniformly dispersed within the gypsum matrix. The multifunctional effects of these additives were comprehensively assessed via integrated mechanical characterization, spectrophotometric whiteness evaluation, and microstructural interrogation. The findings revealed that the incorporation of HGMs resulted in a significant decrease in the NGBC density while concurrently enhancing whiteness; they also exerted an adverse impact on both processability and mechanical properties. Moreover, the fusion of HGMs and SFs within the NGBCs achieved an optimal balance between lightness and strength. The peak density of NGBCs was ascertained to be 1.41 g/cm3, complemented by flexural and compressive strengths of 6.12 and 9.78 MPa, respectively. Such optimizations were realized with HGMs at a particle size of 80 um and a composition of 20 vol.%, alongside sisal fibers present at a concentration of 0.3 vol.%. The current research affords significant revelations regarding the fabrication of architectural gypsum materials that are lightweight, possess high tensile strength, exhibit an aesthetically appealing finish, and demonstrate superior whiteness, presenting a prospective resolution for applications within the high-performance construction sector.