ENVIRONMENTAL TESTS ON A REINFORCED CONCRETE WITH EMBEDDED FBG SENSORS

Abstract: FBG sensors are optical strain gages that offer many advantages over the conventional ones such as a long term stability. This long term stability of the sensor has to be accompanied by durable contact with the structure. For instance when the sensors are used for monitoring a bridge of a highway the glue used to attach the sensor on the metallic reinforcement may be spoiled by the severity of the environment. In this paper a specimen of a reinforced concrete with an FBG sensor glued on the metallic reinforcement has been subjected to thermal cycles. Tensile tests have been performed on the specimen while reading the FBG response. The wavelength shifts of the sensors compared with the readings of the pulling machine has given information on the quality of the adhesion of the sensor to the specimen and consequently on the effect that the environment had on the glue.