Improvement of flammability resistance of epoxy adhesives used in infrastructure applications

Abstract

Fire endurance of fibre-reinforced-polymer (FRP) concrete systems is crucial for safe use of FRPs in the construction industry. Nanoclay was introduced into epoxy resin to retard flame spread and improve the fire endurance of bonds between FRP and concrete. Test results show that the addition of nanoclay can greatly improve the flame retardancy of epoxy. With only 2% nanoclay, the limit oxygen index number of epoxy increases by 5 and 10 using two types of mixing methods developed at the Concordia Centre for Composites. The epoxy with the addition of nanoclay possesses self-extinguishing properties, whereas the epoxy without the addition of nanoclay burned completely. After exposure to 260 °C for 2 h, the FRP-concrete system using epoxy and 2% nanoclay adhesive showed 23% greater average residual bonding strength than that using control epoxy adhesive. The nanoclay used in this study is a nontoxic and inexpensive material that may fulfill the requirements for civil engineering applications.Key words: fire resistance, fibre-reinforced polymer, concrete, bond, adhesive, nanoclay, epoxy.