PSI - Issue 44

Giuseppe Bramato et al. / Procedia Structural Integrity 44 (2023) 2302–2309 Author name / Structural Integrity Procedia 00 (2022) 000–000

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lime-based mortar and AR-glass dry fibre. The results showed that the bond strength was independent from the type of substrate and equal to the 90% and 94% of the FRCM tensile capacity. Lignola et al (2017) conducted a large experimental program on Basalt FRCM composites; 52 tensile tests and 52 single-lap direct-shear tests were executed by ten different university laboratories. The results evidenced that, in general, a lower performance can be expected when grid spacing is reduced, hence the matrix penetration through the fibres is expected to be limited. It was evidenced also that the initial stiffness and cracking stress were particularly sensitive to mortar properties. The present work reports the main results of an experimental campaign organized to enlarge the knowledge on the use of Basalt FRCM system as reinforcement for masonry. At this scope two different substrates, representative of the historical and artistic heritage of Southern Italy (a sedimentary compact stone known as Pietra Leccese and a sedimentary porous stone named as Calcarenite ) and two different mortars (cementitious and lime-based) were studied. The obtained results are listed and discussed in the present work. Nomenclature B Basalt open mesh grid C sedimentary porous stone, “ Calcarenite ” E I FRCM slope of the FRCM in the uncracking phase e u,FRCM deformation of FRCM coupons related to their maximum tensile strength FL free length FM shear-bond test failure mode - according to dei Lavori Pubblici, C. S. (2018) F peak shear-bond maximum load GL gauge length l length of substrate single block l b bond length l s length of FRCM coupon M cementitious mortar PL calcareous compact stone, “ Pietra Leccese ” R lime-based mortar s shear bond displacement 2. Experimental program With the aim to evaluate the mechanical performance of the Basalt-FRCM reinforcement system and the interface stress transfer mechanisms with substrates a large experimental campaign was planned. In the following the experimental data related to 18 direct tensile tests on FRCM coupons and 12 single lap direct-shear tests were discussed. Mechanical proprieties of substrate, mortars and dry fiber were also evaluated. 2.1. Specimens preparation 2.1.1 FRCM Specimens were manufactured by varying the type of mortar while the same basalt dry grid was used. All samples were casted in a single wood formwork applying two 5 mm thick (el) layers of mortar with a fabric layer in between and cured at laboratory environmental conditions (i.e. ~23 ± 2 °C, ~50 ± 5 % RH). The dimensions of the samples (600 ( l s )x100 ( w s ) mm) were chosen according to dei Lavori Pubblici, C. S. (2018). After curing, steel tabs with dimensions of 100 (w s ) x 80 (t l ) mm have been epoxy-glued at the specimen ends aims to strengthening the load s cr,FRCM cracking strength of FRCM coupon s u,FRCM maximum strength of FRCM coupon s peak shear bond maximum strength t single block thickness t l steel tabs length w single block width