Description
To mitigate debonding, FRP anchors such as U-wraps and fiber splay anchors, are typically employed. Fiber splay anchors are often preferred because they are efficient in terms of materials usage and can be applied in locations with geometric constraints or limited space. Given that FRP strengthening systems aim to prolong the service life of structures, ensuring their durability is paramount under harsh environmental conditions. The authors recently conducted a durability study on FRP-strengthened notched concrete beams, involving water immersion at 50 °C for 3,000 hours (per ACI 440.9R) to assess the durability of the fiber splay anchors. The study concluded that specimens experiencing anchor rupture in the bend region exhibited a nearly 25% reduction in capacity following accelerated conditioning. In CFRP composites, carbon fibers are inert to the environment, and therefore do not exhibit deterioration. However, given the complex stress state (i.e., both normal and shear stress components) in the bend region of the anchor, the durability of the fiber anchor is influenced by the degradation of the fiber-matrix interface and polymer matrix. This study evaluates the effects of FRP material-level design parameters (manufacturing method and carbon fiber sizing) on the interlaminar durability of fiber anchors via the short-beam test. The accelerated conditioning protocols employed include hygrothermal, alkali, saltwater and freeze-thaw exposure. The mechanical testing is completed with scanning electron microscopy and atomic force microscopy to identify relevant degradation mechanisms. The study is underway, and results will be reported at SMAR 2024.
