Sensing capability enhancement of multifunctional carbon fiber-sprayed FRP composites fabricated with CNT-modified epoxy

Abstract

The deterioration of infrastructures has been a major issue for numerous countries and has raised concerns for the importance of structural health monitoring. Fiber-reinforced polymer (FRP) composites have been widely used as a conventional retrofitting material, imparting enhanced load carry ing capacity and ductility to the structures. The present study aims at developing a multifunctional FRP coating system which possesses stress/strain sensing capabilities by means of replacing ordinary epoxy resin with epoxy resin modified by carbon nanotube (CNT), which demonstrates enhancement in mechanical'elcctrical properties of composites. The FRP composite prepared in the present work was manufactured on the basis of the sprayed FRP fabrication method, which is one of the structural retrofitting methods, and two types of carbon fiber-sprayed FRP (CSFRP) were fabricated using ordinary epoxy resin or CNT-modified epoxy resin in an effort to compare their sensing performances. The sensing characteristics of the fabricated FRPs were evaluated by means of monitoring electrical resistance change induced in response to the applied stress. In particular, the sensing capability of the CSFRP manufactured with epoxy resin modified by CNT was more stable than that manufactured with ordinary epoxy resin. The preliminary result of the experiments demonstrated that the CSFRP facilitates resilient sensing capabilities as well as the retrofitting functions, which can effectively enhance potential and worth of FRP composites.