PSI - Issue 64

Kevin Isaac Escobar et al. / Procedia Structural Integrity 64 (2024) 1476–1483 Kevin Isaac Escobar/ Structural Integrity Procedia 00 (2019) 000 – 000

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slip. Two LVDTs were mounted in the concrete on both sides of the TRM to measure the relative displacement between the aluminium piece and the concrete, and consequently the mesh’s slippage. Bonded lengths of 200 mm, 300 mm, and 400 mm were studied with both carbon fibres coated with latex and basalt fibre coated with acrylic resin. Additional lengths of 150 mm and 450 mm were studied with carbon textile. Each strip had a nominal width of 60 mm and nominal thickness of 10 mm. Concrete prims had a cross section of 150x150 mm and different heights depending on the bonded length studied. Specimens are designated for both tensile and bond tests using the notation TC_L_W_M, where TC = textile and coating used as given in Table 1, L = length of the specimen or bonded length in the case of shear testing (in mm), W = specimen width (in mm), and M = matrix employed as denoted in Table 2. 3. Results and discussion 3.1. Tensile behaviour The results of the tensile tests on TRM are represented by stress-strain curves, where the stress is the load divided by the nominal sectional area of the textile as indicated in Table 1. Curves for different configurations of TRM are shown in Fig. 3, Fig. 4, and Fig.5. The stress-strain responses of the bare textiles are also included in the figures as reference. Values for the axial strain and axial stress of the TRM at the cracking point and maximum strength are indicated in Table 3. The number of cracks captured in the gauge length has a strong influence on the ultimate strain measured, consistent with was what observed before by D’Antino and Papanicolaou (2017) . The development of a major crack was more likely to be placed near the tabs and outside of the gauge length like observed by Calabrese et al. (2022). Specimens using carbon textile coated with latex resin were not able to achieve the maximum textile strength corresponding to the fibre strength (see Fig. 3). This premature failure was attributed to a weak bond between the mesh and the matrix, resulting in slippage between them. Arboleda et al. (2016) reported similar behaviour between testing procedures for carbon textiles coated with latex resin. It was observed that loss of coating resistance promotes separation between textile filaments, resulting in telescopic failure (Alexandre et al. 2023). Employing epoxy resin for impregnation of carbon textiles considerably improved the overall behaviour of the composite (see Fig. 4). Developed cracks were closer in spacing, allowing the LVDTs to capture more cracks and accurately measure the maximum strain. No slippage or telescopic failure occurs in specimen with epoxy resin. Tensile strength higher than the bare textile resistance were obtained for specimens with epoxy resin.

Fig. 3. Strain-stress curve of TRM using carbon textile coated with latex resin, (a) conventional mortar, and (b) mortar with glass fibres.

Fig. 4. Strain-stress curve of TRM using carbon textile coated with epoxy resin, (a) conventional mortar, and (b) mortar with synthetic fibres.