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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concrete characterization, three cylinders per batch were cast to obtain the concrete compressive strength following the European standard EN 12390-3 (2019).

Table 2. Material properties of mortars and concrete employed.

Notation

Description

Batch

σ flm (N/mm

2 ) [CoV]

σ

c (N/mm

2 ) [CoV]

C1 C2 C3 P1 P2 P3 P4 Z1 Z2

9.0 [1.9%] 9.3 [6.2%] 8.7 [7.9%] 8.7 [12.3%] 6.4 [11.1%] 9.2 [6.8%] 8.7 [4.6%] 8.0 [9.3%] 7.9 [9.3%]

46.6 [4.8%] 49.6 [2.7%] 48.5 [2.8%] 37.3 [2.7%] 34.5 [7.5%] 37.3 [1.4%] 27.9 [2.0%] 48.2 [3.2%] 58.6 [2.0%] 29.5 [5.7%] 33.2 [1.1%]

C

Cement-based mortar

Cement-based mortar with short glass fibres

P

Z

Mortar with synthetic fibres

CR1 CR2

- -

CR

Concrete

2.2. TRM specimens and testing setup Every TRM coupon for tensile testing was made in a phenolic mould. All specimens had a nominal length, width, and thickness equal to 600 mm, 60 mm, and 10 mm respectively. Four and ten bundles in the warp direction for carbon and basalt TRM composites were used, respectively. The tensile tests were conducted on a universal testing machine. Clamping and clevis methods were employed to attach the specimens to the machine. The clamping method consists of two steel plates bolted at each end of the specimen with a rubber sheet between them. The clamped length of the samples between the plates was 170 mm. For the clevis grip method, two metallic tabs were glued at each end of the coupons with epoxy resin. All specimens were given a tabs bonded length of 100 mm following the recommendations of the AC434 (2016), except for carbon impregnated with epoxy resin, for which a bonded length of 200 mm was selected. Tabs bonded length should be selected base on the effective bond length between the textile and the matrix but in the absence of that information a length of 150 mm has proven to be sufficient for different TRM composites. Testing in both methods was conducted under displacement control at a rate of 0.20mm/min. Two linear variable differential transducers (LVDTs) were mounted in the mid span of the composites with a gauge length of 200 mm. LVDTs measurements allowed to compute the TRM strains by dividing them by the gauge length. Setups for the tensile tests are shown in Fig. 2 (a) and Fig 2. (b).

Fig. 2. Configurations for tensile and bond tests: (a) clamping method, (b) clevis grip method, (c) single lap shear method.

A single-lap configuration was employed to perform the bond tests. The single-lap shear test layout is shown in Fig. 2 (c). An aluminium piece was fixed to the bare textile at the outset of the bonded length to monitor the global