Evaluation of Tensile Strength of Glass Fiber Reinforced Polymer Rebars under the Marine Environment - A Durability Approach

Over the past decade, there has been a significant rise in the use of Glass Fiber-Reinforced Polymer (GFRP) bars as internal reinforcement for concrete structures, primarily owing to their remarkable corrosion resistance. However, a critical concern has arisen regarding their susceptibility to degradation in terms of tensile strength and elastic modulus when exposed to harsh alkaline and saline environments. This study specifically focuses on the impact of such environments on two distinct types of GFRP rebars: sand-coated and twisted. The experiment involved subjecting these rebars to an accelerated temperature of 60 degrees Celsius for 180 days. The primary objective is to assess the extent to which GFRP rebars experience a reduction in tensile strength under the influence of moisture, alkaline solutions, and saline conditions. Preliminary findings reveal that the tensile strength of the GFRP rebars underwent a significant reduction during exposure to alkaline conditions. Specifically, the twisted GFRP rebars experienced a 25-30% reduction, while the sand-coated counterparts exhibited a 20% reduction in tensile strength. These observations highlight the vulnerability of GFRP rebars in alkaline environments. Furthermore, the study has identified a 15% reduction in tensile strength for both types of GFRP rebars under the influence of saline conditions. The implications of these reductions are currently the subject of further investigation as the research delves into understanding the effects of alkaline and saline exposure on the overall performance and durability of GFRP bars in concrete structures.