Abstract
Long-term behavior of composite materials is still a controversial issue among the engineering community though fiber-reinforced polymer (FRP) reinforcements are increasingly used in infrastructure applications. The main objective of this study is to investigate the effect of different local environmental conditions on the long-term behavior of glass fiber-reinforced polymer (GFRP) bars in concrete beams subjected to sustained loads. This is achieved through testing concrete beams reinforced with GFRP bars and subjected to a certain stress level. To accelerate the reaction, all beams are either completely or partially immersed in different environments (tap water and seawater) at elevated temperature. Test results are expressed in terms of tensile strength of GFRP bars and load-deflection behavior of both unstressed and stressed beams. The results show that there is significant loss in tensile strength of GFRP bars when subjected to sustained stress for the considered exposure conditions. The results of this investigation will be very useful to engineers concerned with the design of structures using composite materials.