Experimental Investigation of Tensile and Bond Strength for a GFRP–SSWM Hybrid Wraps

This study experimentally investigates the tensile and bond performance of novel GFRP–SSWM hybrid wraps developed using two epoxy adhesives - Sikadur 30 LP and Sikadur 330. A total of 42 coupon specimens for tensile testing and 48 dumbbell specimens for bond testing are prepared using various two-layer and three-layer configurations of GFRP, SSWM, and their hybrids. Tensile tests are conducted as per ASTM D3039, and specimen performance are evaluated in terms of ultimate load capacity, displacement at peak load, stiffness, rupture strain, and failure modes. Fractographic assessment is also performed at the failure plane of coupon specimens. Study results of tensile and bond test, indicate that GFRP-only specimens exhibit high tensile strength and stiffness but fail in a brittle manner, while SSWM-only specimens show greater ductility with reduced strength. Hybrid configurations offer a balanced response between strength and ductility. Among hybrids, GS specimens bonded with Sikadur 30 LP show superior performance in two-layer systems. Fractographic observations confirm effective hybrid action between GFRP and SSWM without delamination or layer separation at the interface. The capacity utilization ratio further supports that Sikadur 30 LP performs better than Sikadur 330, especially in hybrid configurations involving SSWM. The study highlights the mechanical viability of GFRP-SSWM hybrid wraps for use in strengthening applications.