Study of the behaviour of FRP materials and epoxy adhesives under elevated temperature

Abstract

Strengthening using externally bonded FRP is widely adopted to enhance load carrying capacity of structural elements and overall safety of the structures. However, the performance of FRP materials and epoxy adhesives under elevated temperature needs to be addressed. This study mainly focuses on evaluation of tensile performance of Glass Fiber Reinforced Polymer (GFRP) and Carbon Fiber Reinforced Polymer (CFRP) strips as well as behaviour of two different types of epoxy adhesives i.e. Sikadur 30 LP and Sikadur 330 under elevated temperatures. The performance of FRP materials is compared with Stainless Steel Wire Mesh (SSWM), which is a cost-effective alternative for strengthening. A total of 54 number of coupon specimens (strips of size 300 mm × 25 mm) of GFRP, CFRP and SSWM are prepared and tested under uniaxial tension as per ASTM standard. Coupon specimens are exposed to different elevated temperatures i.e. 100℃, 200℃, 300℃, 400℃ and 500℃ for 2 h. For epoxy material, 50 mm long strips of 25 mm width and 5 mm thickness are prepared. From the results, superior performance of SSWM is observed as compared to GFRP and CFRP material at elevated temperature. A complete disintegration of fibers is observed beyond 200℃ for FRP specimens. However, SSWM maintains both the integrity and strength even up to 500℃. Further, from the comparison of integrity and weight loss, it is observed that Sikadur 30 LP performs better as compared to Sikadur 330 at elevated temperature. From the results, it is concluded that SSWM along with Sikadur 30 LP epoxy can be used for the strengthening of concrete structures exposed to elevated temperature. Based on study, it is suggested to further create diverse hybrid composites by combining CFRP, GFRP, and SSWM with appropriate bonding materials for applications in various industries and environmental conditions having exposure to high temperatures.