DURABILITY OF GFRP RODS, LAMINATES, AND SANDWICH PANELS SUBJECTED TO VARIOUS ENVIRONMENTAL CONDITIONING

This paper outlines the performance of glass fiber-reinforced polymeric (GFRP) materials subjected to various environmental conditioning. The study is performed in conjunction with the construction of one bridge using FRP-reinforced concrete panels and three bridges using GFRP sandwich panels. GFRP rods utilizing a urethane-modified vinyl ester resin and GFRP laminates and sandwich panels utilizing an isophthalic polyester resin were subjected to environmental conditions designed to simulate their in-situ environments. Two different conditioning regimens were utilized for each type of GFRP material considered. First, to replicate the exposure of the GFRP rods to an alkaline environment, a solution containing calcium, sodium and potassium hydroxides was formulated with a pH of 12.6; an elevated temperature of 60°C (140°F) was utilized to accelerate absorption. The rods were also subjected to a series of freeze-thaw, high temperature, and high relative humidity cycles in an environmental chamber to duplicate seasonal effects in the mid-west United States. The tensile and interlaminar shear properties of GFRP rods subjected to these conditions are compared to the properties of control specimens. GFRP laminates an