Durability of plain concrete prism strengthened with galvanized steel mesh and CFRP laminates under harsh environmental conditions

Abstract

This paper investigates the bond durability of recently developed galvanized steel mesh (GSM) strengthening systems compared to the carbon fiber-reinforced polymer (CFRP) composites under severe environments. Plain concrete prisms notched at the mid-span and strengthened with medium cord density GSM (MSM), high cord density GSM (HSM), and CFRP-epoxy systems were exposed to the laboratory environment, direct sunlight, and saline water for 180, 360, and 730 days. Prisms were tested under three-point bending after each exposure. The failure mode of the CFRP specimens changed from interfacial to pure adhesive after saline-water and sun exposures only after six months, whereas the MSM and HSM specimens exhibited cohesive failure throughout 730 days of all the exposures. After 730 days of conditioning, no significant loss in the bond strength was observed for the three strengthening systems. On the contrary, the strength retention factor was above 1 for several specimens tested after 360 and 730 days under all exposures. Bond-strength environmental degradation factors are proposed to analyze and design the strengthened reinforced concrete members with such laminates.