Mechanical Characterisation of Polymer Fibre- Reinforced Cement-Based Mortar for Masonry Joint Repointing (original) (raw)
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Engineering Structures, 2016
Details of an experimental program investigating the structural performance of unreinforced masonry (URM) walls strengthened using two different types of polymer textile reinforced mortar (TRM) is presented. The experimental program involved full scale reversed cyclic in-plane and out-of-plane testing of TRM strengthened URM walls. The testing was performed in two series, with series 1 involving inplane testing of two (03) pier-spandrel assemblages representing part of a perforated URM wall and series 2 involving out-of-plane testing of three (03) slender walls having no penetrations. To replicate the physical characteristics of historic masonry materials, vintage solid clay bricks and a low strength hydraulic cement mortar were used for construction of the test walls. Numerous structural characteristics pertaining to the seismic behaviour of TRM strengthened historic URM walls were investigated and then compared to those obtained from corresponding as-built tested URM walls. In general, strengthened walls exhibited a ductile behaviour until the polymer textile ruptured in a brittle manner. The strength increment due to TRM strengthening was observed to range from 128% to 136% when the URM test walls were loaded in-plane and from 575% to 786% when the URM test walls were loaded out-of-plane, with a notable increment in deformation capacity and ductility.
Materials and Structures, 2020
Fiber-reinforced composites can be arranged in the form of bi-dimensional grids and employed as internal reinforcement of mortar plasters to realize composite reinforced mortar (CRM) systems. Recently, CRM were applied as externally bonded reinforcement of existing masonry members showing promising improvements of load-carrying and deformation capacities. However, since CRM systems are still in their infancy, limited research is available regarding their mechanical properties and their bond behavior with respect to masonry substrates. In this paper, a series of experimental tests are performed on a CRM system comprising a glass fiber-reinforced composite grid and a lime-based matrix. Namely, tensile tests of bare grid yarns and of CRM coupons, shear tests of grid joints, and single-lap direct shear tests of CRM-masonry joints were performed. These tests are aimed at providing a comprehensive mechanical characterization of the CRM, which results can be used to design strengthening ap...
Bulletin of the Polytechnic Institute of Jassy Constructions Architecture Section, 2011
Masonry represents the oldest building material in the history. The rehabilitation of a damaged building involves knowledge about the building material's properties, the execution technology, the elaboration of the rehabilitation project and, also, theoretical knowledge about the strength calculus of the rehabilitated structure. All these are required in order to assess the bearing capacity. With the view to determine the strength and deformability characteristics of the old masonry (made from bricks and "bound" with lowstrength mortars), this paper proposes an analysis concerning the mechanical characteristics of the component materials and proposing a new method for testing the mortar adhesion to the "masonry stone" (bricks). The test method involves determining the maximum tensile stress applied by a direct load at right angles to the surface of the mortar. The strength of a mortar can vary. If mixed with higher amounts of portland cement, a harder mortar is obtained. The more lime that is added, the softer and more plastic the mortar becomes, increasing its workability. A mortar strong in compression might be desirable for a hard stone, whereas a softer, more permeable lime mortar, would be preferable for a historic wall of soft bricks. Three different mix proportions were considered in the experimental investigation, made with different binders (lime based, clay based, combination between lime and cement) and one standard cement mortar (for comparison).
State of the Art for Strengthening Masonry with Fibre Reinforced Polymers
The Bulletin of the Polytechnic Institute of Jassy, Construction. Architecture Section, 2012
This paper addresses the modern strengthening techniques used for improving the earthquaqe behaviour of masonry structures, by aid of fibre reinforced polymers (FRP). These type of materials play an important role in the process of overtaking the tensile stresses which masonry by itself is not capable to resist. Also, they proved to have a very good bond strength, both for normal and tangential stresses, with respect to masonry units (fired clay bricks, concrete blocks) and mortar. Basically, the interventions on existing masonry may be concentrated in joints, starting with joints repointing or near surface mounted (NSM), reinforcing techniques, or may be applied on the entire wall or structure, mentioning here jacketing, post-tensioning or center core techniques. Even though structural repointing presents less influence in terms of strength to in and out-of-plane loading than overall applied techniques, their main advantage is represented by the possibility to preserve the original...
Experiments on Reinforced Brick Masonry
2020
1 ACI Structural Journal, V. 107, No. 3, May-June 2010. MS No. S-2009-122.R4 received August 4, 2009, and reviewed under Institute publication policies. Copyright © 2010, American Concrete Institute. All rights reserved, including the making of copies unless permission is obtained from the copyright proprietors. Pertinent discussion including author’s closure, if any, will be published in the March-April 2011 ACI Structural Journal if the discussion is received by November 1, 2010. ACI STRUCTURAL JOURNAL TECHNICAL PAPER
Mechanical Properties of Brick Masonry with Different Types of Bonds
2014
In this research the influence of the type of bonds on mechanical properties of brick masonry is investigated experimentally and analytically. For this purpose English bond style and French bond style were chosen and specimens of each type were constructed to be subjected to compression load. Lower strength of French bond type specimen was obtained and it is believed that this is due to larger volume of mortar used in this type of bond. Since strength of mortar presents lower values than brick units it is reasonable that combination of bricks of larger strength with cement mortar of lower strength produce specimens of lower strength when larger volume of mortar is used. Analytical model were constructed using finite element method (FEM) to estimate elastic modulus of brick masonry. French bond type specimen shows a slight decrease for elastic modulus. Using FEM modelling, curves to estimate masonry properties for different combinations of brick properties and mortar properties can b...
Stiffness plasticity degradation of masonry mortar under compression: preliminar results
Revista IBRACON de Estruturas e Materiais, 2018
The main goal of this research is to determine the mechanical properties of bedding mortar by assessing the mortar damage onset, the stiffness plasticity degradation and the apparent Poisson´s ratio under compression. Two mortar types, 1:0.5:4 and 1:1:6 (cement:lime:sand ratio), were used and tested at 28 days; specimens had diameter-to-height (d/h) ratios of 0.3 and 1.0. These diameter-to-height (d/h) ratios were chosen to evaluate the effect of confinement caused by the friction between the steel plates of the testing machine and the sample. Numerical models were developed, and their response compared with the experimental results. From the experimental results, it was concluded that there are meaningful differences in their responses with weak and strong mortar types and different d/h ratios. The d/h ratio influences the relationship between the stress and strength and the apparent Poisson´s ratio of the specimen, which is defined herein as the ratio of the horizontal to vertical...
Deformation and Failure Mode of Masonry
Masonry is widely used in many parts of the world and one of the challenges engineers face is how to increase the performance of the masonry wall element. There are many possible ways to increase the wall performance including the use of better materials and the designing and enforcing of a high standard quality control and quality assurance program. These possibilities, however, will most likely increase the cost of construction and eliminate the masonry as a viable construction system. Another possible way to increase the wall performance is to better understand the current system and try to modify current conservative code requirements. Although there is an initial research cost, such possibility appears to be more economically feasible in the end. The research presented herein focused on understanding the mechanical properties of the basic block-mortar set, which is responsible for the wall performance and failure. The main goal was assessing the failure mode and deformation cap...