DURABILITY PERFORMANCE OF EPOXY EXPOSED TO DIFFERENT HYGROTHERMAL ENVIRONMENTS

摘要

Fibers by themselves have limited use in engineering applications since they cannot transmitrnloads from one to another; therefore, the matrix material plays an important role in the overallrnfunction of the fiber reinforced polymer (FRP) composites. The matrix for structural compositernmaterials can either be of thermosetting type or of thermoplastic type, with the first being morerncommon. Polyester, Vinyl-ester, and Epoxy are the most commonly used polymeric matrixrnmaterials used in civil infrastructure applications. In the case of FRP bonded concrete structures,rnthe resin materials also play a vital role for the bonding between concrete surface and FRPrncomposite sheet. This paper intends to study the effects of hygrothermal conditions on therndurability performance of epoxy materials. Several sets of epoxy beam specimens have beenrnconstructed and exposed to 23, 100, and 180 ℃ temperature environments with 0 % or 100 %rnrelative humidity. All specimens were subjected to the flexural load test. Flexural strength, midspanrndeflection, stiffness, and as well as the mode of failure have been considered in this study.rnCompared with the 23 ℃ samples, the experimental results showed an improvement in thernflexural strength at 100 ℃ but at 180 ℃ the flexural strength decreased while the reverse wasrnobserved for the stiffness.