Investigation on enhancing fire performance of carbon fibre reinforced polymer (CFRP) strengthened concrete columns

Abstract

This study focuses on the development of an adhesive to bond Carbon Fibre Reinforced Polymer (CFRP) fabric with a concrete substrate which performs well under elevated temperature. The epoxy adhesive which is the generally used adhesive for CFRP has a very low glass transition temperature that results in the loss of adhesive properties at higher temperatures. As a solution, Engineered Cementitious Composite (ECC) mortar mix was developed to function as a cementitious adhesive. ECC was developed using locally available materials. Effective bond length for the developed ECC adhesive is 150 mm and the achieved bond strength is 224.9 N/mm 2 . The bond strength was further enhanced up to 570.28 N/mm

by sticking sand on top of CFRP fabric using epoxy adhesive before bonding it using cementitious adhesive as an interface bond enhancing technique. When the bond temperature was incremented up to 100 0 C, bond strength reduction was less than 5.5%. Another attempt was made to enhance performance of the epoxy adhesive which has been used in CFRP/Concrete composite by blending with Polyethylene terephthalate (PET) fibres as a commercially viable option. Finally it indicated that developed epoxy can be used to strengthen cylinders using CFRP and a 7% of higher axial confinement was achieved when compared with the bond without modification. This modification has enhanced the performance of composite at ambient temperature as well as at elevated temperature when compared with the CFRP/Epoxy/Concrete bond.