Durability Assessment of 15- to 20-Year-Old GFRP Bars Extracted from Bridges in the US. II: GFRP Bar Assessment

Abstract

A multilaboratory investigation into the durability of glass fiber–reinforced polymer (GFRP) bars extracted from eleven 15- to 20-year-old bridges in the US will be performed. Part 1 (Benzecry et al., forthcoming) of this two-paper series describes the bridges and presents data on the condition of their concrete, and Part 2 focuses on the condition of the bars. Constituent content, maximum water absorption, as-received moisture content, glass transition temperature (Tg), short bar shear (SBS) strength, and tensile strength will be evaluated. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) will be performed. The fiber mass content of all bars was close to or greater than that specified in the current ASTM E1309 (ASTM 2011a) GFRP bar standard. SEM and EDS showed only slight signs of degradation, which was predominantly near the outer radius of the bars. The loss of SBS strength was slight to moderate in bars with control data for comparison. Tensile strength, which could only be evaluated in 1 bridge, showed a reduction of only 4.2% after 17 years of service. It was concluded that GFRP bars could be considered a promising replacement for steel reinforcement in bridge decks subjected to real-time field exposure.