Mechanical properties and debonding strength of Fabric Reinforced Cementitious Matrix (FRCM) systems for masonry strengthening

Abstract

a b s t r a c tFabric Reinforced Cementitious Matrix (FRCM) composites are advanced cement-based materials often used for strengthening masonry or concrete structures. The system is usually composed of a dry grid of fibers embedded in a cementitious matrix enriched with short fibers.An important parameter for designing the structural reinforcement is the tensile load-bearing capacity of FRCM composites. For their heterogeneity, FRCM composites show an interesting mechanical behavior in tension, that depends on the properties of the components and of the bonding strength. These values could be estimated with mechanical models but must be validated experimentally by means of proper testing campaigns.In this work several FRCM materials made with different fiber grids were investigated. Four different types of fibers were considered: polyparaphenylene benzobisoxazole (PBO), carbon (C), glass (G) and PBO and glass (PBO-G) fibers and three different types of cementitious mortars.The behavior of FRCM under tension and the influence of the bond properties between the dry textile and the inorganic matrix are studied developing an extensive experimental program that included the characterization both of the materials components and of the composites. A series of push-pull double lap tests and pull-off tests were performed to determine the bonding properties of FRCM composites applied to masonry structures.The paper presents results and considerations that can provide background data for future recommendations for the use of FRCM systems in the rehabilitation of elements.

Application of Short Fibers Reinforced Composites in Power Transmission Coupling

“…The embedded region interaction is defined in Abaqus to remove the intersection volume of the fibers with the matrix from the matrix volume, and create the interaction between them with the bonding strength values. These values are calculated based on the fibers and matrix properties according to the failure criteria discussed in the mechanics of composites book (Tamuzs, 2015) and by Carozzi (2015). The coupling are fixed at the effective area around the bolts holes on the friction sides of the coupling and the load is defined as a pressure on the keyway face as shown in figure 6.…”

“…The bonding interfacial strength is defined as an interaction limiting value between the fibers and matrix. The interfacial bonding strength is calculated according to the procedure found in the mechanics of composites book (Tamuzs, 2015) and the deboning strength of fabrics with cementations matrix research conducted by Carozzi (2015).…”

The Reticulatus method for shear strengthening of fair-faced masonry

“…The utilization of inorganic matrices, based on hydraulic and cement mortars, is thus a desirable device to avoid the use of epoxy or organic resins (Prota et al 2006, Papanicolaou et al 2008, Borri at al. 2014, Gattesco et al 2015, Carozzi and Poggi 2015.…”

Minimal Mass Design of Strengthening Techniques for Planar and Curved Masonry Structures

“…We assume a tensile strength σ b equal to 376.13 MPa, which corresponds to an average value of the bond strengths of the FRP and FRCM reinforcements of masonry structures analyzed in [7,8], respectively (we employed formula (5.6) of [21] to estimate such a strength). Fig.…”

“…Nowadays, it is a common practice to reinforce such structures by applying tensile reinforcements made of traditional materials, such as steel, or innovative high-strength materials [4,5,6]. Strips and/or meshes of materials like Fiber Reinforced Polymers (FRP) or Fabric Reinforced Cementitious Matrix (FRCM) composites are often bonded to masonry structures to improve their mechanical properties [7,8,9]. However, it is worth remarking that such strengthening techniques, when improperly used, may lead to an excessive over-strength of the reinforced structure, and reduced 'cracking-adaptation' capacity [10].…”