Effects of Heat Treatment on Mechanical Properties of Jute Fiber–Reinforced Polymer Composites for Concrete Confinement

Abstract

Some natural fibers such as jute which have high tensile strength can be applied in natural fiber-reinforced polymer (FRP). Natural cellulose fibers are hydrophilic, resulting in lower reinforcement performance. Heat treatment can reduce water content in natural fibers and possibly improve the properties of natural FRP in terms of enhancing fiber and polymer composite action. This paper presents an improvement of jute fiber–reinforced polymer (JFRP) composites by heat treatment. The heat treatment conditions (i.e., temperature and duration) were considered. Coupons of heated JFRPs were tested to investigate their tensile properties. The application of JFRP on confinement was investigated by compression tests on concrete cylinders with JFRP wrapping. The experimental results indicated that a suitable heat treatment condition of 80°C for 24 h can significantly increase the tensile strength of JFRP coupons and the compressive strength of JFRP-confined concrete. The testing results of concrete confinement can be used to validate the existing predicting equations for confined compressive strength. In addition, a new equation was proposed for the effect of heat treatment of JFRP.