Durability and accelerated ageing testing of CFRP repair systems

 ABSTRACT

Epoxy bonded CFRP is a commonly used method of strengthening or repairing concrete structures; however, the long term performance of the epoxy bonded materials is not clearly defined. Accelerated ageing of CFRP specimens has long been a contentious issue since the environmental conditions used during the ageing process are not always present in the field This paper presents a conceptual model for behavior of accelerated ageing, actual test results in water immersion and observed strength reductions. A three point bend test is presented to evaluate the strength degradation due to accelerated and normal ageing of bonded CFRP reinforcement. Critical parameters are found to be inherent epoxy properties and the water content at the CFRP/concrete interface. The three point bend test has a lower coefficient of variation than the direct tension test. A methodology is presented for conducting accelerated geing tests for two field conditions: immersion in water and in air. The accelerated ageing process allows an engineer to prequalify CFRP bonded strengthening systems and to establish a strength reduction factor for a given CFRP system