Compression strength of pre-damaged concrete cylinders reinforced by non-adhesive filament wound composites

In this study, two layers of aluminum foils are inserted between the concrete cylinder and the filament wound composite jacket to form a non-adhesive wrapping for infrastructures. Three kinds of compression damaged concrete cylinders were reinforced by seven kinds of non-adhesive filament wound polymer composites, and the strengths of the composite/concrete systems were investigated. These concrete cylinders were compressed to three pre-damaged states including low-level, medium-level, and high-level damage states such that their residual compressive strengths are, respectively, 84, 75, and 70% that of an original concrete cylinder. These damaged concrete cylinders simulate bridge piers or building cylinders subjected to different magnitudes of stress, or at various stages in a long-term behavior. The damaged concrete cylinders were then non-adhesively filament wound by composite jackets with seven kinds of lay-ups through the combination of three winding angles 45, 60, and 90°. The compression strengths of the composite/damaged concrete systems were evaluated to study the effects of the damaged level of the concrete cylinders and the winding angle of composite wrappings. The failure modes of the composite/damaged concrete systems were examined to evaluate the benefit of this reinforcing methodology.