Use of Fiber-Reinforced Cements in Masonry Construction and Structural Rehabilitation (original) (raw)
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Flexural Strength of Fiber Reinforced Lime Mortars for Historic Masonry Structures
2011
The first author of the project is the engineering director of a Temple reconstruction project in Turkey. In attempt to produce mortar similar in composition to that found at the temple site and employ the use of fibers for mortars increased durability and resistance against in-plane loading, the team prepared an extensive experimental program. This program was carried out for the United States National Park Service (NPS), National Center of Preservation Technology and Training (NCPTT). The materials used in this experimental program are two types of masonry units (fired-clay bricks and concrete masonry units), three types of binder matrices (Portland cement-lime, type N; natural hydrated lime 3.5W, and natural hydrated lime 4W), and 8 types of fibers (5 synthetic versions, goat hair, horse hair, and specially treated corn silk fibers). With the variations in matrix preparations and the fiber volume fractions, 80 mixtures are tested for workability, water permeability, compressive s...
A review on Properties of Fiber Reinforced Cement-based materials
IOSR Journal of Mechanical and Civil Engineering, 2016
Mixing of horsehair and straw with the clay to form floor and bricks was one of the earliest example in which fiber was utilized to strengthen a brittle matrix. Romualdi was first to propose the use of steel fibers as a reinforcement material in his 1963 and 1964 papers. Since then, a plethora of books and papers have been published on the use of various fibers in cement-based material. Published literature shows huge potential of fibers as a reinforcement material. A comprehensive overview of the published literature on the use of fibers in cement-based material is being presented. Effect of fibers on properties of cement-based material such as workability, compressive strength, flexural strength, split tensile strength, shrinkage, impact resistance, fatigue behavior and durability has been presented.
Strengthening of Masonry Structures with Cementitious Matrix Composite
2016
Seismic risk mitigation of historical masonry buildings comprises a challenge of growing relevance for both scientific research and engineering practice. Especially for buildings of high historical value, retrofitting techniques must be compliant with the basic principles of conservation, i.e. non-invasiveness, reversibility and compatibility. In this perspective, fabric-reinforced cementitious matrices (FRCMs) are becoming increasingly suitable for strengthening of historic masonry constructions in seismic areas, as an alternative to Fiber Reinforced Polymers (FRPs) . Cementitious matrix composites are easy to apply, have a resistance against high temperatures comparable with the support, can be applied to damp surfaces, and have excellent physical–chemical compatibility with the masonry substrates. Furthermore, if compared with FRP composites, FRCM composites permit higher vapor permeability, lower costs, and a complete reversibility of the installation. These qualities assume a m...
Proceedings of the Fifteenth International Conference on Civil, Structural and Environmental Engineering Computing
Fibre-reinforced polymers (FRP) have shown to be an effective solution for retrofitting and strengthening of existing masonry structures, although some drawbacks related with the use of organic resins have been found. A newly developed alternative to FRP, known as fibre reinforced cementitious matrix (FRCM) composites, may overcome the drawbacks. This paper provides a better insight into the bond behaviour of FRCM when applied to masonry substrates and highlights possible differences with the behaviour of FRP composites by means of push-pull single-lap direct-shear tests for two types of fibres (glass and basalt). Additionally, the sustainability of this strengthening system was evaluated by means of a life cycle assessment (LCA). The experimental data suggests that the effective bond length for basalt FRCM composites is lower than 260 mm and that for basalt and glass composites the initial response is highly dependent on the elastic behaviour of the fibres. The FRCM system provides environmental benefits in all the analysed categories with respect to the reference FRP technique, based on the analysis performed.
2019
Due to its low tensile strength and brittle behavior, the use of concrete as structural material has required the use of tensile reinforcement, traditionally on the form of reinforcing bars placed on the locations in which high tensile stresses are expected. In previous decades, the use of steel, glass, or plastic fibers dispersed randomly on the fresh concrete mix for the total or partial replacement of reinforcing bars has shown to provide significant increase on the tensile and flexural strength, abrasion resistance, permeability, toughness and durability of concrete. The use of this composite material, known as fiber reinforced concrete (FRC) or mortar (FRM), for industrial pavement, tunnel linings, and hydraulic and precast structures has shown satisfactory results. More recently, the use of FRC and FRM for the strengthening of existing concrete and masonry structures has caught the attention of researchers worldwide. Unfortunately, experimental evidence on the topic is still s...
2020
Recent seismic events prompted research to develop innovative materials for strengthening and repair of both modern and historic masonry constructions (buildings, bridges, towers) and structural components (walls, arches and vaults, pillars, and columns). Strengthening solutions based on composite materials, such as the Fiber Reinforced Polymers (FRP) or the Fiber Reinforced Cementitious Matrix (FRCM), have been increasingly considered in the last two decades. Despite reinforcement made of short-fibers being a topic that has been studied for several years from different researchers, it is not yet fully considered for the restoration of the masonry construction. This work aims to experimentally investigate the enhancement of the mechanical properties of lime-based mortar reinforced by introducing short glass fibers in the mortar matrix with several contents and aspect ratios. Beams with dimensions of 160 × 40 × 40 mm with a central notch were tested in three-point bending configuration aiming to evaluate both the flexural strength and energy fracture of the composite material. Then, the end pieces of the broken beams were tested in Brazilian and compressive tests. All the tests were performed by a hydraulic displacement-controlled testing machine. Results highlight that the new composite material ensures excellent ductility capacity and it can be considered a promising alternative to the classic fiber-reinforcing systems.
2018
Masonry joint repointing has been considered as a procedure for repair and strengthening of brickand blockmasonry walls and a technical solution for improving the seismic resistance of existing masonry buildings. When compared to other available methods, joint repointing requires less material resources and technological processes, it can be easily applied and uses common structural materials. However, only limited amount of experimental data is available in the literature that describe the material and structural behavior of masonry strengthened by joint repointing. In order to understand the mechanical behavior of such material and structure, it is fundamental to perform experimental tests and recognize the material behavior from the undamaged state until failure. Such material characterization is of great importance for accurate mathematical modelling and structural simulation and analysis. This paper presents the results from experimental program leading to mechanical characteri...
Materials
Recent seismic events prompted research to develop innovative materials for strengthening and repair of both modern and historic masonry constructions (buildings, bridges, towers) and structural components (walls, arches and vaults, pillars, and columns). Strengthening solutions based on composite materials, such as the Fiber Reinforced Polymers (FRP) or the Fiber Reinforced Cementitious Matrix (FRCM), have been increasingly considered in the last two decades. Despite reinforcement made of short-fibers being a topic that has been studied for several years from different researchers, it is not yet fully considered for the restoration of the masonry construction. This work aims to experimentally investigate the enhancement of the mechanical properties of lime-based mortar reinforced by introducing short glass fibers in the mortar matrix with several contents and aspect ratios. Beams with dimensions of 160 mm × 40 mm × 40 mm with a central notch were tested in three-point bending confi...
Engineering Structures, 2020
Seismic events highlight the inherent fragility and vulnerability of stone masonry buildings, which represent a large part of the existing historical and artistic heritage. In order to preserve these structures, numerous reinforcement techniques are typically used on masonry walls, including mortar injections, reinforced drilling, and reinforced concrete plaster. Nowadays new and less invasive strengthening techniques are preferred; among them Fiber Reinforced Cementitious Matrix (FRCM) system with lime-based mortar, which is considered to be more compatible with the intrinsic properties of these ancient structures as compared to cement-based mortar. This work aims to investigate experimentally and computationally FRCM applied as reinforcement to ancient stone masonry. In particular, the paper presents results from diagonal compression tests carried out at the University of L'Aquila (Italy) on stone masonry specimens strengthened with layers of Glass-FRCM (GFRCM). In comparison with unreinforced panels, those strengthened by the GFRCM exhibited a significant increase in shear modulus and shear strength. A computational framework based on the Lattice Discrete Particle Model (LDPM) was then used to reproduce the experimental results. The fracture behavior and the damage evolution in masonry panels were investigated under different assumptions on the GFRCM system features (bond behavior, mortar thickness, fiber anchors and fiber grid). The good agreement between experimental results and the LDPM simulations show that this approach predicts well the mechanical behavior and the damage evolution in stone masonry under quasi-static loading conditions. Moreover, it can be considered a viable tool for engineers in developing effective reinforcement techniques.