2021 Volume 70 Issue 5 Pages 155-160
In order to verify the applicability of glass-fiber reinforced plastics with an unsaturated polyester matrix in manhole environments, degradation characteristics in a weak alkaline aqueous solution were evaluated based on solution immersion test. The decrease in flexural strength after immersion test at 313 K fitted well to the logarithmic approximation. Based on Arrhenius equation, we estimated the deterioration behavior under 288 K conditions, which corresponded to a manhole environment. However, since a problem in applying the logarithmic approximation became clear, a more appropriate estimation method is required.