Effect of Variations in Sand Particle Sizes of Fiberglass-Sand Hybrid Composites on Flexural Strength

This study investigates how varying sand particle sizes influence the flexural strength of fiberglass-sand hybrid composites. The composite fabrication process employed a polymer matrix, chopped strand mat (CSM300) glass fiber, and sand as reinforcement. Five distinct sand mesh sizes (12, 16, 20, 24, and 40) were incorporated into the composite specimens. Flexural strength was assessed using a three-point bending method in accordance with ASTM D790 guidelines. The findings revealed that using sand with a mesh size of 16 resulted in a peak flexural strength of 433.2 MPa, marking a 61% improvement over the baseline. However, as the sand mesh size increased beyond this point, flexural strength declined by approximately 50%. This reduction is primarily attributed to the weakened interfacial bonding between the sand particles and the matrix, likely due to the brittle and fragile nature of sand as a ceramic material. Consequently, larger sand particle sizes tend to diminish the overall flexural performance of the fiberglass-sand composite.