Effect of Initial Damage on the Deterioration of GFRP under Acidic Environment.

It is well known that an acid corrosion phenomenon, called environmental stress cracking, appears on E-glass fibers in GFRP. Acid diffusion into a matrix resin, however, does not occur without loading. In this study, the initial damage was observed during pre-stressing by a microscope. The relationship between the initial damage and the generation of AE in the tensile tests under air and acidic environments was examined by using test specimens with or without pre-stressing. SEM observation on the fractured surface of these specimens was also performed. The matrix resins used in the test had different toughness. The observation confirms that the existence of initial damage such as cracks governs the acid corrosion behavior of GFRP. It is found that the cracks, developed as the initial damage, allow acid to transport rapidly in the resin. Eventually, GFRP is easily fractured at a lower stress than the fracture strength of the original GFRP.