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Antonio Nanni - One of the best experts on this subject based on the ideXlab platform.
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direct shear bond tests of fabric reinforced Cementitious Matrix materials
Journal of Composites for Construction, 2020Co-Authors: Francesca Giulia Carozzi, Carlo Poggi, Diana Arboleda, Antonio NanniAbstract:AbstractFabric-reinforced Cementitious Matrix (FRCM) composites consist of a dry fiber fabric embedded in an inorganic mortar that may be enriched with short fibers. These composites are particular...
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acceptance criteria for tensile characterization of fabric reinforced Cementitious Matrix systems for concrete and masonry repair
Journal of Composites for Construction, 2018Co-Authors: Stefano De Santis, Francisco De Caso Y Basalo, Gianmarco De Felice, Houman A Hadad, Antonio NanniAbstract:AbstractFabric-reinforced Cementitious Matrix (FRCM) composites are a new class of materials used to repair and strengthen existing structures. Mechanical performance varies widely based on the typ...
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Corrosion-damaged RC beams repaired with fabric-reinforced Cementitious Matrix
Journal of Composites for Construction, 2018Co-Authors: Mohammed Elghazy, Ahmed El Refai, Usama Ebead, Antonio NanniAbstract:AbstractThe structural performance of corrosion-damaged reinforced concrete (RC) beams repaired with fabric-reinforced Cementitious Matrix (FRCM) was investigated. Eleven RC beams were constructed ...
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Fabric-reinforced Cementitious Matrix behavior at high-temperature: Experimental and numerical results
Composites Part B: Engineering, 2017Co-Authors: Jacopo Donnini, Francisco De Caso Y Basalo, Giovanni Lancioni, Valeria Corinaldesi, Antonio NanniAbstract:The use of externally applied composite systems to upgrade, strengthen or rehabilitate masonry or concrete structures is well established. However, structural strengthening with organic type composites, such as fiber-reinforced polymer (FRP) systems, may be impractical when the element is exposed to high-temperature service conditions, due to significant degradation of the organic resin. Instead, the use of an inorganic Matrix, as in the case of fabric-reinforced Cementitious Matrix (FRCM) composites, may overcome this problem. The purpose of this study is to evaluate the mechanical behavior under high-temperature conditions of FRCM systems. Different FRCM composites are evaluated and include carbon fabrics ranging from dry to highly-impregnated with an organic resin. The experimental spectrum is comprised of uniaxial tensile and double-shear bond tests performed under temperatures ranging from 20 to 120 °C to determine the influence of temperature over the FRCM mechanical properties. Furthermore, SEM analysis was used to study the damage processes at the fiber-Matrix interface post tensile testing. Experimental results show variations in the FRCM mechanical properties if tested at high temperature conditions (caused by the deterioration of the resin coating at the interface fiber-Matrix) while residual performance after exposure to elevated temperatures remains unchanged. FRCM reinforced with dry fabrics has proven not to be affected by temperatures up to 120 °C. A numerical model using a fracture variational approach, based on incremental energy minimization, was also developed to simulate the FRCM behavior in double shear tests under different temperatures exposition.
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effectiveness of fabric reinforced Cementitious Matrix in strengthening reinforced concrete beams
Journal of Composites for Construction, 2016Co-Authors: Usama Ebead, Ahmed El Refai, Kshitij C Shrestha, Muhammad Shekaib Afzal, Antonio NanniAbstract:AbstractThis paper reports on the efficiency of fabric-reinforced Cementitious Matrix (FRCM) in enhancing the flexural capacity and deformational characteristics of RC beams. In the main experimental part of the paper, 12 RC beams, 2,500 mm long, 150 mm wide, and 260 mm deep, were fabricated. The beams had two different steel reinforcement ratios, namely, ρsD12=0.72% and ρsD16=1.27%, representing typical underreinforced beam sections. The strengthened beams utilized two FRCM types, carbon and polyparaphenylene benzobisoxazole (PBO) FRCM systems. In the second part of the work, tensile material characterization tests were performed on the FRCM coupons to determine the tensile characteristics of the FRCM composites. The beams were tested in flexure under four-point loading until failure. Two beams without FRCM strengthening were used as a benchmark. Six beams were externally strengthened using one, two, and three layers of carbon FRCM system. Four beams were strengthened with one and two layers of PBO FRCM ...
Carlo Poggi - One of the best experts on this subject based on the ideXlab platform.
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direct shear bond tests of fabric reinforced Cementitious Matrix materials
Journal of Composites for Construction, 2020Co-Authors: Francesca Giulia Carozzi, Carlo Poggi, Diana Arboleda, Antonio NanniAbstract:AbstractFabric-reinforced Cementitious Matrix (FRCM) composites consist of a dry fiber fabric embedded in an inorganic mortar that may be enriched with short fibers. These composites are particular...
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new italian guidelines for design of externally bonded fabric reinforced Cementitious Matrix frcm systems for repair and strengthening of masonry and concrete structures
Procedia structural integrity, 2018Co-Authors: Luigi Ascione, Tommaso Dantino, Francesca Giulia Carozzi, Carlo PoggiAbstract:Abstract The paper summarizes the main features of a standardization activity carried out in Italy by the Ministry of Public Works, to which two of the authors have taken part, for the homologation and the acceptance of Fabric-Reinforced Cementitious Matrix (FRCM) composites. During the last years, such composite materials have becoming increseangly popular in the civil engineering field for strengthening existing constructions, even if difficulties can occur in their mechanical characterization that is strongly affected by different and complex failure mechanisms. The American ACI 549.4R-13 is currently the only available guideline for design and construction of these systems. In this framework, the paper describes the Italian proposals for the homologation process of FRCM materials as well as for the design of strengthening interventions with these composites. Comparisons with the American guideline are also reported together with some considerations regarding the different partial safety factors.
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testing procedures for the uniaxial tensile characterization of fabric reinforced Cementitious Matrix composites
Journal of Composites for Construction, 2016Co-Authors: Diana Arboleda, Antonio Nanni, Francesca Giulia Carozzi, Carlo PoggiAbstract:AbstractFabric-reinforced Cementitious Matrix (FRCM) composites made of dry-fiber fabric embedded in an inorganic Matrix are advanced cement-based materials designed for retrofitting masonry or concrete structures. Characterization of the tensile behavior of FRCM composites provides the parameters needed for the design of the structural reinforcement and has given rise to numerous research studies on the aspects that influence its mechanical properties. To obtain the tensile behavior characteristics of this composite under different boundary conditions, two test setups were investigated. A clevis grip (pin action) was used to reproduce field boundary conditions from typical installation and to obtain design parameters. A clamping grip was used to obtain a complete characterization of the composite by inducing a tensile failure of each constituent material. Several FRCM systems made with different fabrics were used for the investigation: polyparaphenylene benzobisoxazole (PBO), carbon (C), and glass (G), p...
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mechanical properties and debonding strength of fabric reinforced Cementitious Matrix frcm systems for masonry strengthening
Composites Part B-engineering, 2015Co-Authors: Francesca Giulia Carozzi, Carlo PoggiAbstract:Abstract Fabric 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.
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numerical modeling of fabric reinforce Cementitious Matrix composites frcm in tension
Construction and Building Materials, 2014Co-Authors: Elisa Bertolesi, Francesca Giulia Carozzi, Gabriele Milani, Carlo PoggiAbstract:Abstract Existing masonry structures often need to be strengthened or repaired. In many cases, the intervention is realized using composite materials bonded to the surface of the structural element. In many masonry structures the use of fabric reinforced Cementitious matrices (FRCM) is preferred to the fiber reinforced polymers (FRP). The typical experimental stress–strain behavior exhibited by a FRCM composite under a direct tensile test is a tri-linear curve with a first phase that increases linearly according to mortar Young’s modulus, a second phase where the cracks in the mortar start to grow, and a last phase in which the mortar is fully cracked and the curve assumes the same slope of the stiffness of the fabric. According to a wide experimental campaign conducted on the subject at the Politecnico di Milano, the curves exhibit a relatively wide scatter, especially in the second phase, making the standardization of the direct tensile test a rather difficult task. With the aim of having an insight into the observed experimental variability, a comprehensive FE numerical analysis was conducted and is presented in this paper. Two different FE codes were utilized. One with less sophisticated material models, the second with the possibility to deal with softening and damage in the post peak range. The use of commercial codes instead of home-made models was voluntary, with the precise final aim of enabling other researchers the reproduction of results with similar models and for analogous experiments. Three different variables that can affect the mechanical behavior in tension were examined (non-planarity of the composite grid, bending of the specimen and pre-existing micro-cracks), leading to three different sets of simulations. A final objective of the numerical simulation was to study and compare possible constitutive models for the Cementitious Matrix to simulate the experiments. At this aim, three different material models were used for mortar belonging to FRCM specimens in tension. The numerical results obtained satisfactory reproduce experimental evidences and provide a justification of the relative large scatter of the data.
Francesca Giulia Carozzi - One of the best experts on this subject based on the ideXlab platform.
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direct shear bond tests of fabric reinforced Cementitious Matrix materials
Journal of Composites for Construction, 2020Co-Authors: Francesca Giulia Carozzi, Carlo Poggi, Diana Arboleda, Antonio NanniAbstract:AbstractFabric-reinforced Cementitious Matrix (FRCM) composites consist of a dry fiber fabric embedded in an inorganic mortar that may be enriched with short fibers. These composites are particular...
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new italian guidelines for design of externally bonded fabric reinforced Cementitious Matrix frcm systems for repair and strengthening of masonry and concrete structures
Procedia structural integrity, 2018Co-Authors: Luigi Ascione, Tommaso Dantino, Francesca Giulia Carozzi, Carlo PoggiAbstract:Abstract The paper summarizes the main features of a standardization activity carried out in Italy by the Ministry of Public Works, to which two of the authors have taken part, for the homologation and the acceptance of Fabric-Reinforced Cementitious Matrix (FRCM) composites. During the last years, such composite materials have becoming increseangly popular in the civil engineering field for strengthening existing constructions, even if difficulties can occur in their mechanical characterization that is strongly affected by different and complex failure mechanisms. The American ACI 549.4R-13 is currently the only available guideline for design and construction of these systems. In this framework, the paper describes the Italian proposals for the homologation process of FRCM materials as well as for the design of strengthening interventions with these composites. Comparisons with the American guideline are also reported together with some considerations regarding the different partial safety factors.
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experimental analysis on tensile and bond properties of pbo and aramid fabric reinforced Cementitious Matrix for strengthening masonry structures
Composites Part B-engineering, 2017Co-Authors: Carmelo Caggegi, Stefano De Santis, Francesca Giulia Carozzi, Francesco Fabbrocino, Francesco Focacci, łukasz Hojdys, Emma Lanoye, Luigia ZuccarinoAbstract:Abstract The use of Fabric Reinforced Cementitious Matrix (FRCM) composites appears as a compatible and effective technique to strengthen masonry structures. The use of FRCM composites in place of FRP (fiber reinforced polymer) composites provides noticeable advantages in terms of fire and heat resistance and vapor permeability. These characteristics are of primary importance in the field of the strengthening historical buildings and monuments. This justifies the attention of the scientific community to the mechanical behavior of the FRCM materials with the aim to define exhaustive strengthening design guidelines. The experimental research presented in this paper involves direct tensile tests and single lap shear tests. It was carried out in the framework of the Technical Committee Rilem TC 250 CSM (Composites for the Sustainable Strengthening of Masonry). Specifically, this paper concerns FRCM systems comprising PBO (polyparaphenylene benzobisoxazole) or Aramid textiles.
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glass fabric reinforced Cementitious Matrix tensile properties and bond performance on masonry substrate
Composites Part B-engineering, 2017Co-Authors: Marianovella Leone, Francesca Giulia Carozzi, Maria Antonietta Aiello, Alberto Balsamo, Francesca Ceroni, Marco Corradi, Matija Gams, Enrico Garbin, Natalino GattescoAbstract:Fibre-reinforced composite materials have gained an increasing success, mostly for strengthening, retrofitting, and repairing existing structures. However some problems may arise with the use of traditional FRP (Fiber Reinforced Polymer), particularly when the compatibility with the substrate and the reversibility of the intervention are required, as in case of cultural heritage buildings, or specific exposition conditions may compromise the long term effectiveness of the reinforcement, as in presence of high temperature and humidity. Starting from these considerations new composite materials are emerging as a more effective solution in certain fields of application and under specific service conditions; in this context, mortar-based composite systems, consisting of one or more layers of uni- or bi-directional fibre nets embedded in cement/lime-based Matrix layers, can be used as reinforcement of both concrete and masonry structures. However, the research work dealing with these emerging materials and their performances when used as a strengthening system for existing structures is still limited. Both experimental and theoretical investigations are needed in order to deliver reliable design methodologies. In this work, a Round Robin Test aimed to the characterization of both bond with the existing substrate and tensile performance of glass fabric (in the form of grids) coupled with inorganic mortar matrices is presented. The investigation was conducted at fifteen laboratories involved in the RILEM Technical Committee 250-CSM (Composites for the Sustainable Strengthening of Masonry). With the aim of studying the bond behaviour between Fabric Reinforced Cementitious Matrix (FRCM) composites and masonry substrate, single and double lap shear tests were carried out on brick-masonry prisms. Results provide useful informations about the mechanical properties, the bond capacity and the failure mechanisms of different commercially available glass FRCM systems. Finally, critical aspects are underlined to address the progress of the research work.
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testing procedures for the uniaxial tensile characterization of fabric reinforced Cementitious Matrix composites
Journal of Composites for Construction, 2016Co-Authors: Diana Arboleda, Antonio Nanni, Francesca Giulia Carozzi, Carlo PoggiAbstract:AbstractFabric-reinforced Cementitious Matrix (FRCM) composites made of dry-fiber fabric embedded in an inorganic Matrix are advanced cement-based materials designed for retrofitting masonry or concrete structures. Characterization of the tensile behavior of FRCM composites provides the parameters needed for the design of the structural reinforcement and has given rise to numerous research studies on the aspects that influence its mechanical properties. To obtain the tensile behavior characteristics of this composite under different boundary conditions, two test setups were investigated. A clevis grip (pin action) was used to reproduce field boundary conditions from typical installation and to obtain design parameters. A clamping grip was used to obtain a complete characterization of the composite by inducing a tensile failure of each constituent material. Several FRCM systems made with different fabrics were used for the investigation: polyparaphenylene benzobisoxazole (PBO), carbon (C), and glass (G), p...
Andrea Nobili - One of the best experts on this subject based on the ideXlab platform.
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mechanical performance and crack pattern analysis of aged carbon fabric Cementitious Matrix cfrcm composites
Composite Structures, 2018Co-Authors: Cesare Signorini, Andrea Nobili, Federico Oyedeji FalopeAbstract:Abstract We discuss the effect of environmental exposure on mechanical performance of impregnated Carbon Fabric Reinforced Cementitious Matrix (CFRCM) composite. Following the recently published ICC-ES AC434 guidelines, mechanical performance of prismatic composite specimens is determined on the basis of tensile uni-axial tests. Exposure to saline and alkaline aqueous solutions is considered at 28- as well as 60-day curing time. Special emphasis is placed on crack pattern evaluation as a mean to gain better insight into Matrix/fabric bond quality. To this aim, the evolution of the average crack spacing and of the average crack width is determined as a function of strain for all test environments and curing times. It is found that curing time plays a significant role in mitigating the detrimental effect of aggressive environments. Furthermore, the average crack spacing provides a very reliable measure of Matrix/fabric bond degradation at all test stages.
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impregnated carbon fabric reinforced Cementitious Matrix composite for rehabilitation of the finale emilia hospital roofs case study
Journal of Composites for Construction, 2017Co-Authors: Andrea Nobili, Federico Oyedeji FalopeAbstract:AbstractIn this paper, the mechanical performance of concrete beams strengthened by an impregnated carbon fabric–reinforced Cementitious Matrix (CFRCM) composite is investigated. The study is aimed...
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on the effect of curing time and environmental exposure on impregnated carbon fabric reinforced Cementitious Matrix cfrcm composite with design considerations
Composites Part B-engineering, 2017Co-Authors: Andrea Nobili, Cesare SignoriniAbstract:Abstract This paper investigates the effect of curing time and aggressive environmental exposure on the mechanical performance of impregnated Carbon Fabric Reinforced Cementitious Matrix (CFRCM) composite. Following the recently published IIC-ES AC434 guidelines, saltwater, distilled water, alkali and acid resistance are investigated together with freeze-thaw cycles. Mechanical characterization is based on tensile uni-axial tests under deformation control of rectangular-base prismatic specimens. 28- and 60-day curing times are considered for the control environment as well as for saltwater and alkali resistance. Deformation is monitored via digital acquisition. Besides uni-axial tests, experimental results comprise optical and scanning electron microscopy, crack pattern analysis and failure mechanism assessment. Focus is set on the determination of the design limits for the composite system at failure for the tested environments and curing times. In particular, a comparison is drawn with established design criteria already coded for FRP systems, which introduce the concept of safety (or partial) factors. Environmental conversion factors are also defined and calculated on a statistical basis in a twofold manner, as a mean to determine the design strain and strength limits of exposed specimens from the control (unexposed) data. It is found that they provide a convenient method for assessing the composite vulnerability to the aggressive environments at different curing times.
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durability assessment of impregnated glass fabric reinforced Cementitious Matrix gfrcm composites in the alkaline and saline environments
Construction and Building Materials, 2016Co-Authors: Andrea NobiliAbstract:Abstract In this paper, the effect of the alkaline and of the saline environments on prismatic specimens of impregnated alkali-resistant Glass Fabric Reinforced Cementitious Matrix (GFRCM) coupons is investigated. Two types of mortar are considered as representative of a mid-high performance or fine-texture Matrix. Coupons are manufactured, cured for 28 days and then submerged in the alkaline or saline solution at constant temperature in a climatic chamber for 1000 h (aging). Specimens in the control group are retained in the laboratory environment. Mechanical performance of the aged coupons is assessed through tensile testing. A Digital Image Correlation (DIC) system is used to measure the actual specimen deformation. Ultimate strength and elongation, uncracked and cracked Matrix elastic moduli, turning point location and failure mechanisms are determined and compared with the control group’s through a variance analysis. Statistical support is found for an important reduction in the ultimate strength and elongation, owing to mortar degradation. This result is confirmed by a similar analysis carried out on the single components (mortars and glass fabric) of the composite. Mortar degradation affects failure through favoring a less desirable fabric slip mechanism, as opposed to fabric rupture.
Federico Oyedeji Falope - One of the best experts on this subject based on the ideXlab platform.
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mechanical performance and crack pattern analysis of aged carbon fabric Cementitious Matrix cfrcm composites
Composite Structures, 2018Co-Authors: Cesare Signorini, Andrea Nobili, Federico Oyedeji FalopeAbstract:Abstract We discuss the effect of environmental exposure on mechanical performance of impregnated Carbon Fabric Reinforced Cementitious Matrix (CFRCM) composite. Following the recently published ICC-ES AC434 guidelines, mechanical performance of prismatic composite specimens is determined on the basis of tensile uni-axial tests. Exposure to saline and alkaline aqueous solutions is considered at 28- as well as 60-day curing time. Special emphasis is placed on crack pattern evaluation as a mean to gain better insight into Matrix/fabric bond quality. To this aim, the evolution of the average crack spacing and of the average crack width is determined as a function of strain for all test environments and curing times. It is found that curing time plays a significant role in mitigating the detrimental effect of aggressive environments. Furthermore, the average crack spacing provides a very reliable measure of Matrix/fabric bond degradation at all test stages.
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Double lap shear test on steel fabric reinforced Cementitious Matrix (SFRCM)
Composite Structures, 2018Co-Authors: Federico Oyedeji Falope, Luca Lanzoni, Angelo Marcello TarantinoAbstract:Abstract The present work deals with the experimental characterization of the mechanical bond behaviour of a galvanized steel fabric reinforced Cementitious Matrix (SFRCM) laminated on concrete support. The specimens, made of two low strength concrete blocks connected with a galvanized steel fabric embedded in a geo-polymeric mortar layer, have been tested according to double lap test (DLT) set-up. Six different groups of specimens have been tested varying both the lamination length and the steel fabric density. In order to reproduce the load-slip or bond-slip curves, a tri-linear bond slip model together with its parameters identification has been proposed. For some specimens, the slip profile and the slip distribution have been analysed and split into the substrate laminate slip and inner laminate layers slip. This distinction has been used as a measure of the fabric-Matrix compatibility. In addition, the effect induced by the rigid blocks rotation occurred during the DLT has been argued. The DIC optical system monitoring has been used to asses both the force-slip distribution and the crack opening displacement (COD).
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impregnated carbon fabric reinforced Cementitious Matrix composite for rehabilitation of the finale emilia hospital roofs case study
Journal of Composites for Construction, 2017Co-Authors: Andrea Nobili, Federico Oyedeji FalopeAbstract:AbstractIn this paper, the mechanical performance of concrete beams strengthened by an impregnated carbon fabric–reinforced Cementitious Matrix (CFRCM) composite is investigated. The study is aimed...
