GFRP Reinforcement in Concrete after 15 Years of Service

Glass fiber-reinforced polymer (GFRP) composite bar is emerging as a feasible and economical solution to eliminate the corrosion problem of steel reinforcements in concrete structures; thus, confirmation of its long-term durability is crucial. The objective of this study is to investigate the performance of GFRP bars exposed to concrete alkalinity and ambient conditions after 15 years of service. In order to monitor possible changes in GFRP and concrete, samples were extracted from a bridge for various types of analysis. Carbonation depth and pH of the concrete surrounding the GERP bars were measured. Scanning electron microscopy (SEM) imaging and energy dispersive X-ray spectroscopy (EDS) were performed on GFRP coupons. Finally, GFRP horizontal shear strength, glass transition temperature (T (q)), and fiber content were measured and compared with the results of similar tests performed on control samples at the time of construction. The SEM and EDS did not show any sign of GFRP microstructural deterioration or change of chemical composition, and T-g and fiber content were comparable to pristine values while the results of the horizontal shear strength were inconclusive. This study adds new evidence to the validation of the long-term durability of GFRP bars as concrete reinforcement in field applications. (c) 2017 American Society of Civil Engineers.