Durability of reinforced concrete beams strengthened by galvanized steel mesh-epoxy systems under harsh environmental conditions

Abstract

Strengthening and rehabilitation of reinforced concrete (RC) structural elements are being efficiently carried out by fiber-reinforced polymer (FRP) composite materials. However, their long-term durability is still causing concerns for the repairing industry. Recently, the use of steel wire mesh-epoxy systems for strengthening is gaining the attention of researchers and engineers and their long-term durability warrants investigation. This paper presents the results of an extensive experimental study carried out on 60 RC beams strengthened in flexure by medium and high cord density galvanized steel mesh (MSM, HSM). In order to evaluate the durability of these strengthening systems, the RC beams were exposed to direct sunlight and immersed under saline water for 6, 12, and 24 months. The beams were tested under four-point bending till failure after each exposure period. The MSM and HSM strengthened beams showed up to 51 and 62% higher load-carrying capacity than that of the control beams at 28 days, respectively, and up to 82% after two years of sun and saline water exposure. Furthermore, the exposed beams showed significant delay in crack initiation, no pronounced degradation in strength or stiffness, and no delamination of epoxy. On the contrary, there was significant improvement in the strength of the exposed beams, especially that of the MSM. Based on ACI 440.2R-17 Guidelines, environmental reduction factors were proposed for the exposed beams. This study showed that galvanized MSM and HSM laminates could be promising and durable alternative materials for rehabilitation, retrofitting, and strengthening of RC members under harsh climatic conditions of elevated temperature, high salinity, and high humidity.