Influence of elevated temperatures on the bond behaviour of GFRP bars to concrete – pull-out tests

This paper presents experimental investigations on the bond behaviour between concrete and glass fibre reinforced polymer (GFRP) rebars at moderately elevated temperatures. Pull-out tests were performed on two types of ribbed GFRP rebars, embedded in concrete cylinders, from ambient temperature up to 300 °C; in these tests, the influence of the rebars’ diameter (8 mmvs.12 mm) was also investigated. Specimens were first heated up to the predefined temperature (measured at the GFRP-concrete interface) and then loaded up to failure. The results obtained confirmed that the stiffness and strength of the GFRP rebars-concrete interface suffer significant reductions with temperature; results were also compared with those obtained in a similar experimental campaign performed by the authors, in which sand-coated GFRP rebars were used: this comparison showed that the bond strength of ribbed rebars is significantly less affected by temperature than that of sand-coated ones.