The use of fiber-reinforced polymer (FRP) materials has become a key to enhancing the performance of existing structural elements. Debonding is a common failure mode when FRP sheets are used for the flexural or shear strengthening of reinforced concrete (RC) members. Anchoring the end of FRP sheets with carbon fiber (CF)-reinforced spike anchors, which are typically small, is a proposed method to prevent or delay debonding failure. In the case of seismic strengthening or repair, large-diameter CF anchors are required due to the high demand on structural members. Given the limited available data on large-diameter CF anchors, a challenge in this field is the use of large-diameter CF anchors for conventional RC structures exposed to seismic events. Thus, a testing program was developed to examine the behavior of large-diameter CF anchors. The behavior of CF anchors was examined via a pull-out test for various fanning angles ranging from 45 degrees to 60 degrees. The obtained test data for a given fan angle can be used to enhance the performance of RC structural members in terms of resisting seismic events.