Experimental and theoretical study of the creep behavior of GFRP-reinforced polymer concrete

Composite beams made of polymer concrete unreinforced and reinforced with glass fiber plastic bars have been submitted to long-term creep tests in a four point bending set-up at room temperature. Polymer concrete is a kind of concrete where natural aggregates such as silica sand or gravel are binded together with a thermoset resin, such as epoxy. There is no portland cement in polymer concrete. Polymer concrete, like traditional concrete, presents a poor response in tension. Therefore, polymer concrete beams were reinforced in the tension region with pultruded profiles made of polyester resin and glass fibers. In this work it is reported the creep behavior of polymer concrete beams with and without reinforcement. An analytical model was developed to explain the creep experimental results of reinforced beams. The model assumed linear elastic behavior of GFRP rebars and linear viscoelastic behavior of polymer concrete. The theoretical analysis proved to be enough accurate to predict the creep strain of reinforced beams under loads between 15% and 45% of failure load.