Tensile Properties of Carbon Fiber-Textile Reinforced Mortar (TRM) Characterized by Different Anchorage Methods

Abstract

In the present study, tensile tests were carried out to investigate the tensile behaviors of textile reinforced mortar (TRM) composite specimens. The TRM specimens were composed of one layer of carbon fibers, as the reinforcement, and aluminum cement-based mortar, as the matrix. The primary parameter of the test specimens was the anchorage method, which was newly developed to improve the tensile behavior of the composite: spreading the ends of fiber filaments, reinforcing the ends of fiber filaments using glass fiber reinforced polymer tabs or steel rebars, and coating the ends of fiber filaments with aluminum oxide powder. From the test results, it was found that most TRM specimens using developed anchorage methods exhibited ductile behavior. Moreover, the use of the developed anchorage methods could increase the cracking strength and peak strength of the composite specimens up to 66.1 and 97.9%, respectively. The failure mode of the test specimens was governed by a partial rupture of carbon fibers, except for the BASE specimen and specimen reinforced with steel rebars. Finally, the tensile stress-strain relationship of TRM specimens was idealized as bilinear stress-strain response curves following the guidance specified in ACI 549.4R-13.

Tensile Behaviors of Lap-Spliced Carbon Fiber-Textile Reinforced Mortar Composites Exposed to High Temperature

“…The geometrical properties of textile reinforcement used in this study are presented in Figure 1b. Note that the textile reinforcement was fabricated in the laboratory, and has the same details as that presented in the study by Kim et al [29]. As shown in Figure 1b, the textile reinforcement has the constant space of grid (from mid-bundle to mid-bundle) of 20 mm in both directions.…”

“…The lap splice was also fabricated in the laboratory. The development of 200 mm lap splice length of textile reinforcements was higher than the minimum requirement (51 mm) specified in AC434 [30] and was based on the previous test results [29]. Two separated carbon fiber meshes were set to overlap each other to a length as required.…”

“…Such premature failure of the mortar matrix was attributed to the use of clamping grips inducing the compressive stress concentration to the specimen ends [31]. Moreover, according to Kim et al [29], in some cases, the cracks could occur in the transition zone, which was also influenced by the clamping pressure. Consequently, the CFRP tabs in the gripping areas were lengthened to the transition zones so as to avoid such cracks (see Figure 2).…”

“…In Figure 4a, prior to testing, the gripping areas of the TRM test specimens were clamped with a couple of steel plates, and then fastened by six bolts. This clamping method was selected based on the studies by Kim et al [29] and Leone et al [37]. The clamping force induced by the fastening force of these six bolts was considered to be the gripping pressure applied to the test specimens.…”

Effect of Harsh Conditions on the Tensile Behaviour of Lap-Spliced Carbon Fiber Textile-Reinforced Mortar (TRM) with Different Surface Treatment Methods

“…Thus, a steel bar which could rotate freely around a hinge ( Figure 8a) was used to connect the TRM coupons with a testing machine. This clamping method was also used in the studies of Truong et al [39] and Kim et al [41]. To perform the tensile tests, a universal testing machine (UTM) with a loading capacity of 1000 kN was utilized.…”