Fiber Reinforced Polymer (FRP) Composites for Construction

The development and application of new materials is one of the main driving forces of technical development in the field of civil engineering. Compared with traditional structural materials, a fiber-reinforced composite (FRP) has the advantages of being light weight, high strength, and corrosion resistant while also having designability [1,2]. Over a very long period of time, fiber composite materials have experienced a history of trials, demonstrations, development, and popularization. Now, they are widely used in existing structure reinforcements and various new structures, which can effectively improve structural performance and prolong structural life [3,4]. This Special Issue is dedicated to showcasing the latest research and development activities related to the utilization of FRP composites in construction. This Special Issue on Fiber Reinforced Polymer (FRP) Composites for Construction features 13 papers. All these contributions effectively address the main topics of this Special Issue in a targeted effort.

In line with the research topics explored in this Special Issue, the 13 published articles can be categorized into 3 major themes. The first research topic is the mechanical behavior of FRP. Paper [5] offers a comparative analysis of the flexural response of concrete beams reinforced with different types of FRPs and steel, with a specific focus on CFRP, which shows improved performance at lower reinforcement ratios. Paper [6] investigates fracture models for X80 pipeline girth welds; the 3D model outperformed the 2D model. Tensile strength was correlated with stress triaxiality. Paper [7] investigates shear loads for single non-metallic bars and concrete specimens with non-metallic reinforcements crossing two joints, showing that the behavior after exceeding adhesion was ductile in comparison to joints without reinforcements, where the behavior was brittle. Paper [8] investigates the effects of different target temperatures and cooling methods on the tensile properties of GFRP and derives the prediction equations and theoretical models for the mechanical properties after high-temperature cooling. Paper [9] conducts tests on nine specimens, comparing the superior deformation resistance of GFRP-reinforced concrete (RC) joints to RC beam-to-column joints and validating the experimental results with a proposed core zone shear capacity method. Paper [10] examines the impact of elevated temperatures on the mechanical properties of FRP composites, providing key insights into their performance post-heat exposure and laying the groundwork for fire safety considerations.

The second research topic is strengthening and rehabilitation techniques with FRP. Paper [11] assesses the use of AR-GT fabrics to increase the flexural capacity of RC beams, demonstrating significant improvements in load-carrying capacity with both internal and external layer applications. Paper [12] introduces three different strengthening methods, with the wrapped CFRP method demonstrating the most significant enhancement in carrying capacity and ductility. The paper also includes a theoretical calculation of the carrying capacity. Paper [13] introduces a dispersed-tendon cable anchor system for BFRP cables, aiming to increase anchoring efficiency, an innovation that could influence the design of future FRP anchoring systems. Paper [14] presents an experimental study on the shear behavior of masonry walls reinforced with FRP, indicating notable enhancements in strength and ductility, especially with CFRP composites.

The third research topic is the bonding properties of cementitious materials. Paper [15] investigates the interfacial properties between lightweight concrete (LWC) and engineered cementitious composites (ECC) with different polyvinyl alcohol (PVA) and glass fiber dosages under different surface roughness conditions. Paper [16] investigates the interfacial bonding behavior between high toughness resin concrete with steel wire mesh (HTRCS) and concrete and proposes an interfacial bond-slip model and a bearing capacity equation. Paper [17] examines the types, characteristics, and identification of damage and defects that were either observed or expected in EB-FRP concrete elements.

The research presented in this Special Issue encapsulates a diverse spectrum of investigative and practical advances, demonstrating the transformative impact of FRP composites across various construction scenarios. From innovative methods to robust models, these papers significantly enhance the design, assessment, and execution of construction projects. As the research unfolds, the pivotal role of FRP composites in the evolution of modern construction is both illuminated and affirmed.