Ibrahim Uddin Bhuiyan, Md Israfil Hossain Rimon, Md. Mashuk, Abu Yousouf Siddiky, Md.Thohid Rayhan, Md Hosne Mobarak
: This study develops and characterizes a five-layer hybrid epoxy sandwich composite reinforced with woven jute fabric, short betelnut husk fibers, and date seed granules—three abundant agricultural byproducts—fabricated via hand lay-up with ambient curing. Flexural and compressive tests (ASTM D7264 and D3410) yielded flexural strength of 49.98 ± 1.59 MPa, flexural modulus of 507.72 ± 18.45 MPa, compressive strength of 57.48 ± 0.16 MPa, and compressive modulus of 1470.3 ± 12.08 MPa. A comparison against neat epoxy revealed that fiber/filler reinforcement increased compressive strength by 18% (57.48 vs. 48.6 MPa control) while flexural strength decreased by 17% (49.98 vs. 60.3 MPa control), indicating compressive performance enhancement offset by reduced bending capability due to 8.33% void content. The composite exhibits semi-ductile behavior (6.7% flexural strain) suitable for moderate-load structural and semi-structural applications in automotive interiors, building cladding, and protective packaging. Statistical analysis (one-way ANOVA, α = 0.05) confirmed highly reproducible fabrication (all p > 0.05, CV < 3.7%), demonstrating that accessible hand lay-up methods can achieve consistent mechanical performance. This work validates waste valorization of locally available agricultural residues while providing technology accessible to small-to-medium enterprises in resource-constrained developing economies.