Tensile characterization of multi‐ply fabric‐reinforced cementitious matrix strengthening systems

Abstract

Fabric reinforced cementitious matrix (FRCM) is a composite consisted of highstrength fibers impregnated in a cement-based mortar, and is commonly used for strengthening reinforced concrete and masonry structures. Comprehending the tensile behavior of FRCM is important to achieve a reliable and accurate design of FRCM strengthening systems. The current paper reports on the results of an experimental study on the tensile characterization of FRCM. A total of 40 FRCM specimens (410 × 50 mm, varied in thickness) were prepared and tested. The tensile characterization tests were conducted according to AC 434 guidelines using clevisgrip mechanism. The tests were used to assess the effect of two parameters:(a) fabric type (carbon/glass) and (b) number of fabric plies (one/two/three/four).The results showed that the tensile strength of carbon-FRCM specimens was approximately 1.33 times that of the glass-FRCM counterparts. Three distinct failure modes were observed, namely, (a) ductile fabric slippage in carbon-FRCM (up to three plies of fabric); (b) brittle fabric delamination in carbon-FRCM with four plies of fabric;and (c) brittle fabric rupture in glass-FRCM systems. The FRCM tensile loadcarrying capacity had proportionally increased with the number of fabric plies; less significant effect (within 20%) was observed on the corresponding ultimate tensile stresses (considering the net fabric area as the effective area). K E Y W O R D Scomposite, fabric-reinforced cementitious matrix, mechanical characterization, strengthening, textile reinforced concrete, textile reinforced mortar

Vigas de concreto armado reforçadas segundo a técnica TRM: Revisão sistemática da literatura

“…Pela pesquisa realizada percebe-se que vários autores avaliaram o comportamento a tração da matriz argamassa-grelha (Hartig et al, 2008;Contamine et al, 2011;Si Larbi et al, Contamine et al, 2014;Larrinaga et al, 2014;Mobasher et al, 2014; Contamine e Si Larbi, 2016;Rambo et al, 2017;Kong et al, 2017;D'Antino e Papanicolaou, 2018;Munck et al, 2018;Ortlepp, 2018;Kim et al, 2018;Ebead e El-Sherif, 2019;Li et al, 2019;Younis et al, 2020;El Kadi et al, 2020). Este ensaio é utilizado para determinação do diagrama tensão versus deformação do compósito e, também, para obtenção do módulo de elasticidade.…”

“…Este ensaio é utilizado para determinação do diagrama tensão versus deformação do compósito e, também, para obtenção do módulo de elasticidade. Diversas geometrias de corpos de prova de tração foram encontradas, entretanto, o formato de placa de TRM retangular é a mais amplamente utilizada (Hartig et al, 2008;Larrinaga et al, 2014; Contamine e Si Larbi, 2016;Ebead et al, 2017;Younis et al, 2020). Verificou-se, também, que diversos métodos para fixação dos corpos de prova de TRM à máquina de ensaio são utilizados.…”

“…A técnica TRM/TRC foi proposta para resolver alguns problemas das técnicas NSM (Near-Surface Mounted) e EBR (Externally Bonded Reinforcement). Neste sentido, Younis et al (2020) afirmam que a técnica TRM mostrou-se com capacidade de superar alguns problemas que foram identificadas nas técnicas predecessoras. Citam-se, por exemplo, a sensibilidade ao fogo e ações térmicas no FRP (Gao et al, 2016), dificuldade de aplicação em superfícies molhadas ou exteriores irregulares (colunas, arcos e paredes de alvenaria) que requerem preparação da superfície (Bakis et al, 2002), incompatibilidade da resina epóxi com o substrato de concreto, muitas vezes levando ao descolamento precoce do material de reforço (Buyukozturk et al, 2004;Ebead e Saeed, 2013), a exposição da resina epóxi e o FRP a ação da umidade, raios UVA e UVB, que levam a degradação (Ferreira, 2019;Sarti Junior, 2020) como alguns tipos de problemas enfrentados pela técnica EBR.…”

Experimental procedures for the mechanical characterization of composite reinforced mortar (CRM) systems for retrofitting of masonry structures

“…To overcome these issues, the organic resin can be replaced by inorganic binders and the continuum fiber sheet by open-mesh textiles to form inorganic-matrix composites usually referred to as fiber-reinforced cementitious matrix (FRCM) composites [8]. In FRCM composites, the inorganic matrix provides vapor permeability, protects the embedded textile from UV ray exposure, and is responsible for the stress-transfer mechanism between the composite and the substrate [9][10][11]. The reinforcing textiles can be made by various high-strength fibers, such as carbon, glass, basalt, polyparaphenylene benzobisoxazole (PBO), and steel, whereas cement-based, lime-based, and geopolymer matrices can be employed [12].…”

Strengthening of reinforced concrete beams in shear using different steel reinforced grout techniques

“…The increasing demand to upgrade civil infrastructure has resulted in advanced systems for innovative strengthening and rehabilitation particularly in the use of composites. 1,2 Such strengthening systems include fiber reinforced polymer (FRP) applied using either the externally bonded (EB) technique [3][4][5][6][7][8] or the near-surface mounted [9][10][11][12][13] technique, the EB fabric reinforced cementitious matrix (FRCM), 2,[14][15][16][17][18] the near-surface embedded (NSE) FRCM, 19 and the hybrid NSE/EB-FRCM. 20,21 These composites are usually comprised of carbon, basalt, glass, and/or polyparaphenylene benzobisoxazole (PBO) fibers embedded within organic matrices (generally epoxy resin) in FRP and fabrics embedded within the cementitious matrix in FRCM.…”