The Experts below are selected from a list of 4362 Experts worldwide ranked by ideXlab platform

Zhaoxia Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Influence of Interfacial Material Pore Structure on the Strength of the Brick/Lime Mortar Bond
    Historic Mortars, 2012
    Co-Authors: Mike Lawrence, Peter Walker, Zhaoxia Zhou
    Abstract:

    This paper builds on previous work investigating the flexural bond strength, initial shear strength and compressive strength of fired clay Brickwork built using hydraulic lime mortars. It has been shown that whilst flexural bond strength and initial shear strength of the Brickwork generally increased with mortar strength, flexural bond strength was significantly impaired by both low and high brick water absorption. This paper describes a study of the pore size distribution of the surfaces of brick and mortar at the brick/mortar interface using Mercury Intrusion Porosimetry. The paper identifies critical pore sizes at the brick surface which would appear to govern resultant bond strength.

  • Development of bond strength in hydraulic lime mortared Brickwork
    2012
    Co-Authors: Zhaoxia Zhou
    Abstract:

    The first recorded use of hydraulic lime in construction can be traced back to at least two thousand years ago. Hydraulic lime, produced through either adding pozzolanic materials or calcining clay containing limestone, unlike air lime, can set and harden under water, developing strength through initial hydration reaction and subsequent carbonation. After WWII Portland cement mortars had almost completely replaced lime based mortars in modern construction. However, through conservation and specialist construction the benefits of hydraulic lime are becoming increasingly recognised. To support wider usage of these mortars there is a need for systematic study on the mortar properties and structural performance of lime mortared masonry. This thesis presents findings from a research programme conducted to develop understanding of the mechanical properties of natural hydraulic lime (NHL) mortared Brickwork. The work focussed on the flexural strength of NHL mortared Brickwork. A variety of material and environmental factors, including lime grade and supplier, mix proportion, sand type and age, have been investigated. In addition the research has completed an in-depth study on the influence of brick absorption characteristics on bond development. The two methods of flexural wall panel and bond wrench testing to establish flexural strength have been compared. In addition to flexural strength, initial shear strength and compressive strength of Brickwork has also been investigated. A greater understanding of NHL mortared Brickwork performance has been developed through this work. Performance of the Brickwork has been related to properties of constituent materials and environmental factors. Recommendations for design performance of materials have been provided.

  • influence of interfacial material pore structure on the strength of the brick lime mortar bond
    2012
    Co-Authors: Mike Lawrence, Peter Walker, Zhaoxia Zhou
    Abstract:

    This paper builds on previous work investigating the flexural bond strength, initial shear strength and compressive strength of fired clay Brickwork built using hydraulic lime mortars. It has been shown that whilst flexural bond strength and initial shear strength of the Brickwork generally increased with mortar strength, flexural bond strength was significantly impaired by both low and high brick water absorption. This paper describes a study of the pore size distribution of the surfaces of brick and mortar at the brick/mortar interface using Mercury Intrusion Porosimetry. The paper identifies critical pore sizes at the brick surface which would appear to govern resultant bond strength.

S W Garrity - One of the best experts on this subject based on the ideXlab platform.

  • clay Brickwork and its potential contribution to sustainable infrastructure
    2012
    Co-Authors: S W Garrity
    Abstract:

    As we strive to achieve more sustainable forms of construction, factors such as the thermal mass of a material; its local availability; maintenance demands; ease of maintenance; opportunity for re-use; the amounts of embodied energy and embodied carbon, to name a few, all gain greater significance. Many of these aforementioned factors are inter-dependent and are influenced by durability. Experience shows that well-fired clay Brickwork can be extremely durable. This point is illustrated from a brief review of the performance of two distinctly different structures, both built in the UK, subjected to very severe exposure conditions and a lack of planned maintenance over a prolonged period of time. The first of these is a Saxon church built, in 664, from the remains of an earlier Roman fort. The second is a multi-span railway viaduct built between 1882 and 1884. In both cases the Brickwork has remained in excellent condition and, where repair work has been necessary, it has been much easier to implement than is the case with other more commonly used construction materials. The longevity of clay brick construction and the scope to re-use bricks both result in a material that has a very low level of embodied energy per unit of time. In spite of these potential benefits, clay Brickwork now tends to be used in the UK as a non-structural cladding material for buildings. It is rarely used for engineering structures. This is due, primarily, to the long construction periods when compared with steel and reinforced concrete construction. The principal purposes of this paper are to identify the potential of clay Brickwork to contribute to sustainable design solutions; to encourage those engaged in building and civil engineering structure design to consider clay Brickwork as a structural material for new build and to summarise the main challenges facing designers.

  • the rehabilitation of a victorian clay brick railway viaduct
    2010
    Co-Authors: S W Garrity
    Abstract:

    Larpool viaduct is a 13 span clay brick viaduct built between 1882 and 1884 to carry the Scarborough and Whitby railway across the picturesque Esk Valley in Whitby, North Yorkshire, England. The structure is of multi-ring clay brick arch construction supported on solid Brickwork piers founded on mass concrete or concrete filled Brickwork caissons. The railway was closed to rail traffic in 1965 but was re-opened to pedestrian and cycle traffic in 2000; it is now part of a regional sustainable transport network used mainly by tourists. Exposure to wind, driving rain and repeated freeze-thaw cycles has resulted in severe spalling of some of the Brickwork, particularly that from the 30m high piers. This paper describes the original construction, the rehabilitation works including the historical context of the structure, site inspections prior to and during construction and a review of the rehabilitation works taking into account factors such as differential movement and the need to achieve a high standard of workmanship.

  • MODERN Brickwork HIGHWAY STRUCTURES
    1995
    Co-Authors: S W Garrity
    Abstract:

    Clay Brickwork is set to reemerge as a major structural material with the growing emphasis on designing aesthetically pleasing highway structures with low maintenance costs. This paper addresses the use of clay Brickwork construction for new highway structures such as earth retaining walls, short-span arch bridges and bridge abutments, piers, parapets, and wingwalls. The performance of existing masonry structures is appraised, the principal design requirements for new Brickwork structures are identified, and recent research and development is summarized. Two recently completed bridges with major elements of structural clay Brickwork construction are described in brief.

  • prestressed clay Brickwork bridge abutments research design and construction
    BRIDGE MANAGEMENT 2: INSPECTION MAINTENANCE ASSESSMENT AND REPAIR. PAPERS PRESENTED AT THE SECOND INTERNATIONAL CONFERENCE ON BRIDGE MANAGEMENT HELD 1, 1993
    Co-Authors: S W Garrity, S E Bell
    Abstract:

    Vertically prestressed clay Brickwork cellular or "diaphragm" walls may be a viable alternative to brick clad reinforced concrete for highway structures such as bridge piers, abutments and retaining walls. In this paper, the results of tests of laterally loaded prestressed Brickwork diaphragm walls are summarised, the design methods proposed for such walls are reviewed in the light of this research and the recently constructed prestressed Brickwork bridge abutments designed by Cambridgeshire County Council are described. (A) For the covering abstract of the conference see IRRD 858602.

Peter Walker - One of the best experts on this subject based on the ideXlab platform.

  • Experimental investigation of Brickwork behaviour under shear, compression and flexure
    Construction and Building Materials, 2013
    Co-Authors: J. Wang, Andrew Heath, Peter Walker
    Abstract:

    This paper presents the basic material performance data for an engineering blue brick and a hydraulic premixed mortar which can be used to validate numerical models. The shear behaviour of Brickwork mortar joints under normal compression was studied and the influence of specimen moisture content at the time of testing on strength was investigated. Tests were performed on Brickwork walls to study the shear failure under flexure and different shear loading configurations. A linear relationship between the shear strength and applied normal stress has been established, with different parameters defined for the mortar and the brick/mortar interface. The experimental results are compared to Eurocode 6 predictions and theoretical calculations. It is concluded that Eurocode 6 is conservative for this masonry type.

  • Influence of Interfacial Material Pore Structure on the Strength of the Brick/Lime Mortar Bond
    Historic Mortars, 2012
    Co-Authors: Mike Lawrence, Peter Walker, Zhaoxia Zhou
    Abstract:

    This paper builds on previous work investigating the flexural bond strength, initial shear strength and compressive strength of fired clay Brickwork built using hydraulic lime mortars. It has been shown that whilst flexural bond strength and initial shear strength of the Brickwork generally increased with mortar strength, flexural bond strength was significantly impaired by both low and high brick water absorption. This paper describes a study of the pore size distribution of the surfaces of brick and mortar at the brick/mortar interface using Mercury Intrusion Porosimetry. The paper identifies critical pore sizes at the brick surface which would appear to govern resultant bond strength.

  • influence of interfacial material pore structure on the strength of the brick lime mortar bond
    2012
    Co-Authors: Mike Lawrence, Peter Walker, Zhaoxia Zhou
    Abstract:

    This paper builds on previous work investigating the flexural bond strength, initial shear strength and compressive strength of fired clay Brickwork built using hydraulic lime mortars. It has been shown that whilst flexural bond strength and initial shear strength of the Brickwork generally increased with mortar strength, flexural bond strength was significantly impaired by both low and high brick water absorption. This paper describes a study of the pore size distribution of the surfaces of brick and mortar at the brick/mortar interface using Mercury Intrusion Porosimetry. The paper identifies critical pore sizes at the brick surface which would appear to govern resultant bond strength.

  • Shear reinforcement for Brickwork beams using ferrocement
    Journal of ferrocement, 1997
    Co-Authors: Peter Walker, M Damo
    Abstract:

    Applications using reinforced Brickwork are limited by the material's low shear strength. Unlike concrete, transverse shear reinforcement is not readily incorporated into solid Brickwork sections. This paper considers the feasibility of using an external ferrocement coating to provide shear strengthening. Initially the paper reviews past work in this area, including the use of ferrocement for the retrofit of concrete and masonry structures. Results ofa preliminary experimental investigation, undertaken to assess the use of ferrocement for shear reinforcement, are summarized. A total of six Brickwork/ ferrocement composite beam tests were undertaken, in which the amount oftensile and shear reinforcement provided were varied The future potential ofthis technique is discussed and proposals for further work briefly outlined.

Mike Lawrence - One of the best experts on this subject based on the ideXlab platform.

Antonio Brencich - One of the best experts on this subject based on the ideXlab platform.

  • Brickwork under eccentric compression: Experimental results and macroscopic models
    Construction and Building Materials, 2009
    Co-Authors: Antonio Brencich, Gianmarco De Felice
    Abstract:

    Abstract The compressive strength of masonry is a relevant mechanical parameter playing a central role in the assessment of masonry structures. In spite of a large number of experimental data and theoretical approaches, the failure of Brickwork pillars and arches, its dependence on the properties of the constituents and on the loading conditions is not yet clear. In this paper, the compressive response of solid clay brick masonry is analyzed on the basis of a series of experimental tests performed on Brickwork prisms made with different constituents, either old and new clay bricks arranged with cement and lime mortar, subjected to both concentric and eccentric loading with different load eccentricities. The tests have been displacement controlled in order to reproduce, in terms of both load–displacement and moment–curvature diagrams, the whole response curve, including the post-peak branch. According to the plane section hypothesis, one-dimensional constitutive models of Brickwork, suitable for engineering application, are formulated to represent the non-linear behaviour of masonry. The comparison between theoretical predictions and experimental data, also derived from literature, represented in the axial force–bending moment failure domain, point at the adequacy of the models in estimating the load bearing capacity under eccentric loading, provided that the inelastic response is properly taken into account.

  • Eccentrically loaded Brickwork: Theoretical and experimental results
    Engineering Structures, 2008
    Co-Authors: Antonio Brencich, Clara Corradi, Luigi Gambarotta
    Abstract:

    The assessment procedures for masonry arches and columns usually assume homogeneous constitutive models for which strength and stiffness parameters are described in terms of a uni-axial constitutive law. The limits of such an approach are seldom discussed and related to the Brickwork inhomogeneity, i.e. to the brick size and to the masonry bond. In this paper, a first theoretical and experimental approach to concentric and eccentric loading of solid clay Brickwork are developed and discussed, investigating the failure modes and the compressive strength of masonry and their dependence on the strength, on the geometry of the constituents and on the loading conditions. A mechanical model for the load carrying capacity of eccentrically compressed Brickwork prisms, based on the Static Theorem of Limit Analysis, is proposed allowing: (i) the compressive strength to be related to the size of bricks and mortar joints, showing that edge effects at the free edges do not significantly affect the global behaviour of the material; (ii) the limit domains in the axial force-bending moment space to be derived. Moreover, a series of Brickwork prisms have been tested with different load eccentricities; the comparison with the theoretical approach provides upper and lower bounds to the load carrying capacity of the material and shows that: (i) Brickwork exhibits limited inelastic strains that need to be taken into account to explain the experimental data; (ii) plastic models for masonry overestimate the actual load carrying capacity. On the basis of these results, one-dimensional homogenized constitutive models, suitable for applications, are formulated and their effectiveness supported by the experimental results.

  • mechanical response of solid clay Brickwork under eccentric loading part i unreinforced masonry
    Materials and Structures, 2005
    Co-Authors: Antonio Brencich, Luigi Gambarotta
    Abstract:

    The mechanical response of solid clay Brickwork in presence of CFRP near-surface reinforcement and under eccentric loads is addressed in this paper. Experimental tests on CFRP reinforced masonry (CFRP-RM) prisms under eccentric loads are compared to similar tests on URM specimens in order to give a preliminary insight in the collapse mechanisms of CFRP-reinforced masonry. While URM is found to exhibit a quasi-brittle response, so raising objections to several analytical procedures for masonry bridge assessment, CFRP reinforcement may be responsible of a significant increase in the Brickwork compressive strength and ductility. Some considerations on the cracking processes inside reinforced masonry prisms are discussed.

  • compressive strength of solid clay brick mansory under eccentric loading
    2002
    Co-Authors: Antonio Brencich, Luigi Gambarotta, C Corradi, G Mantegazza, E Sterpi
    Abstract:

    Arches, vaults and pillars generally experience eccentric normal force. As a consequence, the classical theories of masonry collapse, developed for concentrically compressed Brickwork, are not directly applicable. In this paper experimental data on solid clay brick and limemortar masonry prisms, eccentrically loaded, are presented. Comparing the results to the response of a FEM model, some hints on the collapse mechanism of masonry show that the edge effects greatly affect the load carrying capacity of the Brickwork. Besides, the plane section assumption is found to be acceptable up to the ultimate compressive strength, allowing relatively simple models to be used for arch-type structures.