Fe modelling of CFRP-concrete interface subjected to cyclic temperature, humidity and mechanical stress

Modelling of environmental effects on the bond surface between FRP composites and concrete is crucial for the purpose of life prediction of strengthened members. The service performance of composite systems depends on the degree of chemical and physical aging of the system. Physical aging is a reversible process which is related mainly to temperature fluctuations. Chemical aging is the permanent molecular level degradation of fibres, resin or interfaces due to long-term exposure to the environment. The resulting strength reduction and the system behaviour due to aging are important in evaluating the strengthening of civil engineering infrastructure. In this paper, a finite element model is developed to predict the interface properties after long-term exposure to the cyclic temperature and the constant humidity. Effects of sustained loading are also taken into account. The predicted strength, cracks pattern, failure mode and strain variation along the bond line agree well with test results.