Life prediction of thermal aging of adhesive for retard‐bonded prestressed tendons

The effectiveness of the adhesive was an important guarantee for the retard‐bonded prestressing technology. This study concentrated on quickly and reasonably predicting the service life of the adhesive. Samples of the adhesive were exposed in air circulating ovens set at 170, 190, and 210°C for various periods of time. The tensile shear strength of unaged and aged samples was tested. Two life prediction methods based on performance degradation data were presented in this paper. The improved Arrhenius model could improve the credibility and accuracy of extrapolation results meanwhile explains the non‐Arrhenius characteristics of adhesive at low temperature. The lifetime prediction result of the neural network model was close to that of the improved Arrhenius model. The conclusion is that the aging lifetime of adhesive is more than 70 years at an environment below 40°C. The research results provide direct and effective reference value for the life prediction of accelerated failure tests of adhesives.