## 1 Introduction  
Reinforced concrete (RC) is the most popular composite material in structures since the 20 th century owing to its economic efficiency, availability, and mechanical properties. However, exposure to a marine environment may rapidly degrade the durability of RC structures as the reinforcing bars are constantly corroded by chloride attacks [1, 2]. To prevent such chloride attacks, certain design regulations are followed to maintain the minimum cover depth for RC members, and the void between concrete and reinforcing bars is minimized via effective construction. Furthermore, to coat the surface of reinforcing bars with epoxy, a technology was developed [3, 4] to prevent the chloride ions from corroding the bars; however, this technology was applied only to a limited number of bridges owing to the decreased coating effect and the occurrence of local corrosion when the coating layer is peeled off or torn during concrete pouring [5]. Moreover, the surface epoxy coating may lead to bond problems between the bars and concrete [6]. Since the 1970s, several studies considered the application of fiber-reinforced plastics (FRPs) with a strong resistance to corrosion when used as the reinforcement for concrete structures, rather than using reinforcing bars, to prevent chloride attacks on RC structures [7]. FRP reinforcement was primarily applied to bridge slabs in the form of bars, using glass, carbon, and aramid fibers as reinforcing fibers [7, 8]. Recently, the development of grid-type FRP reinforcement [9] and FRP tendons [10] led to the expansion of applying FRP reinforcement to various structures, including building walls [11], external strengthening of structures [12, 13], and bridge foundations. Among them, the grid-type FRP reinforcement is a type of textile reinforcement for textile-reinforced concrete (TRC) structures [14] that uses fibers woven in grid form as the reinforcement for concrete. Typical textile reinforcement is produced by only weaving fibers, such as glass, aramid, carbon, and basalt fibers, in grid form without impregnating them with resin. Although the grid-type FRP reinforcement exhibits higher tensile strength than reinforcing bars, the absence of plastic deformation capacity results in rapid brittle fracture after reaching the tensile strength [7]. Several researchers [15; 16] reported that when fibers are impregnated or coated with resin such as FRP reinforcement, the tensile behavior of TRC members is improved in terms of smaller crack spaces, enhanced stable crack geometry, and increased maximum load. The flexural behavior of TRC members differs from that of RC members [17] because textile reinforcement with physical properties different from reinforcing bars are used as the reinforcement for concrete (Figure 1). In other words, a linear elastic behavior is observed, similar to that in RC members, before the occurrence of cracks. However, the continuous occurrence of multiple cracks results in the transformation of tensile stress to textile reinforcement at the crack cross-section; no new cracks occur after the crack formation stage, where the load hardly increases. As cracking is stabilized and textile reinforcement resists the load, the load gradually increases owing to the increase in deformation, leading to failure because of the non-homogeneous pull-out between the fibers that constitute the textile reinforcement or the fracture of the textile reinforcement. The flexural behavior of TRC members was analyzed considering the textile reinforcement that uses fibers not impregnated with resin. However, only a few studies evaluated the flexural behavior of TRC members reinforced with grid-type FRP reinforcement that impregnates fibers with resin [18; 19; 20]. These studies also used grid-type FRP reinforcement with a small strand spacing of less than 50 mm in the wet and warp directions and a small strand cross-sectional area because of the high tensile strength of FRPs.