Durability of Mortar and Epoxy Bonded Galvanized Steel Mesh Sheets to Concrete Surfaces

Abstract

Over the last few decades, fiber-reinforced polymer (FRP) sheets and plates have been extensively used as external strengthening materials and proved to be quite effective in enhancing the flexure and shear strength of reinforced concrete (RC) beams. Recently, galvanized steel mesh (GSM) composite sheets have emerged as a promising strengthening material due to its desirable mechanical properties and light-weight. However, very limited studies have been conducted to investigate the durability of bond behavior of GSM sheets to concrete surfaces, especially when subjected to harsh environments. Therefore, the main aim of this study is to investigate the bond behavior of GSM sheets attached externally to concrete surfaces via epoxy adhesive (SME) or cement-based mortar (SMM). Both systems were subjected to sun light and saline water exposures for up to a 12 months period. This study will examine the degradation of flexural and bond strength in RC beams, flexural bond prisms, mechanical properties of coupon laminates, and single-lap shear pullout specimens strengthened with both systems. The test results showed that RC beams strengthened with SME laminates achieved an initial increase of 55% in its load carrying capacity and retained 99 and 95% of its strength after 360 days of saline water and sun light exposures, respectively. However, RC beams strengthened with SMM laminates achieved an initial increase of 50% in its load carrying capacity and retained 71 and 74% of its strength after 360 days of exposure in saline water and sun light, respectively. Thus, it could be concluded that SME strengthening system is the best strengthening system that experienced the least degradation in both exposures when compared with SMM strengthening systems. The outcomes from this research will aid in developing environmental factors (CE) for each exposure and test method that could be used in the design and analysis of externally bonded RC beams in the UAE and countries with similar harsh environmental exposures.