Evaluation of material and structural performances of developed Aqua-Advanced-FRP for retrofitting of underwater concrete structural members

FRP is widely used as an effective repair solution for rehabilitating degraded structural members in various conditions. However, in case of submerged structural members, FRP retrofitting becomes ineffective due to its incompatibility to aquatic conditions such as deficient underwater material characteristics, long duration required curing, and low attaching epoxy bond strength in wet conditions. In this study, Aqua-Advanced-FRP (AAF) is developed with newly invented aqua epoxy to enhance the underwater retrofitting methods. To verify the performances of AAF, material and structural tests were carried out. For the material properties of AAF, compressive strength, tensile strength, flexural strength, thermal expansion coefficient, hardening shrinkage strain, and chemical resistance capacity were tested. For the structural performances of AAF retrofitted members, bond strength, compressive strength, flexural strength, and column test on concrete specimens attached with AAF were conducted. The test results showed that the developed AAF drastically improves the structural performances of retrofitted members in underwater conditions with stable behavior.