Abstract: The FRP durability test often takes the ultimate strength measured by the destructive test as the index to measure the performance degradation of the FRP. However, as a polymer material, the performance of FRP is affected by many factors such as the production process, composition ratio, etc. The individual difference of the material is great, and the data of the destructive test in different stages is relatively large. Therefore, in this paper, based on the elastic modulus as the index of the FRP durability test, the destructive test and the homogeneous test of the Same Non-failure durability of the CFRP grid under the three working conditions of aqueous solution, seawater solution and seawater dry and wet cycle were carried out. The conversion relationship between the elastic modulus and the tensile strength was established by using the principle of consistent strain in the corroded and uncorroded areas of materials. Compared with the traditional durability destructive testing method, the same non-failure testing method has the advantages of small data fluctuation, consistent data benchmark, low test cost and material saving, etc. The results show that after 360 days of aging, the retention rate of elastic modulus and tensile strength are 96.9%, 96.8% and 96.1%, and the retention rate of tensile strength are 93.8%, 89.8% and 89.1%, respectively. CFRP has good durability in water-immersed environment. The durability measured by elastic modulus is similar to the durability test results of tensile strength, and can be converted to each other through transformation relationship. It is more reasonable and scientific to evaluate the FRP durability by using the durability prediction model based on the relationship between elastic modulus and tensile strength measured by the same non-failure test method.

Key words: durability, the non-failure test, CFRP, elastic modulus