Service Life Prediction of Gfrp Rebars in an Alkaline Environment

This study proposes a model that predicts the degradation of a GFRP rebar exposed to an alkaline environment, and based on this estimate, predicts the service life of the GFRP rebar. The alkaline environment was a pH 12.6 solution of 0.16% calcium hydroxide, 1% sodium hydroxide, and 1.4% potassium hydroxide, and the GFRP rebar was immersed for 300 days. We performed a tensile test to measure the degradation. The measured tensile strength for each time period was the remaining residual tensile strength (as a percentage) of the reinforcing GFRP rebar under a controlled state. The time shift factor was taken as the time at which the residual tensile strength was 80% of the control strength. A rebar immersed in an alkaline solution for 300 days at 80 °C was calculated to have a TSF of 13,125 days, or about 36 years, under normal South Korean regional conditions, based on the statistics of Korea's mean annual temperature. This study provides a more appropriate model for the environment of Korea than the one suggested by Dejke.