Abstract

Modern earth masonry utilises conventional methods of extruded fired brick manufacturing for the manufacture of unfired earth bricks. However, the bricks produced currently are not generally recommended for structural applications due to their loss of strength under elevated moisture content. In response to this loss in strength, bricks can be chemically stabilised, typically by the addition of cement or lime. However, the use of such binders typically negates the reduced environmental impact of using unfired brick, which is often the initial driver. The research presented in this paper considers the improvement in compressive strength that can be achieved through the addition of a range of pozzolanic binders as well as their associated embodied energy and carbon dioxide. This allows for a holistic comparison of material selection based on meeting the minimum structural requirements of the masonry units, while improving the embodied impact of equivalent units currently used. The study shows that an unfired brick with the addition of lime and metakaolin achieves a compressive strength of more than 6 MPa when dry and more than 1 MPa following complete saturation, while reducing the global warming potential by more than 30%. This paper demonstrates that stabilised unfired bricks can be practically viable, structurally suitable and environmentally beneficial.
Original languageEnglish
Pages (from-to)261-270
Number of pages10
JournalProceedings of the Institution of Civil Engineers: Construction Materials
Volume169
Issue number5
Early online date27 Oct 2015
DOIs
Publication statusPublished - 1 Oct 2016

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Brick
Earth (planet)
Lime
Compressive strength
Binders
Global warming
Carbon Dioxide
Environmental impact
Carbon dioxide
Cements
Moisture

Keywords

  • brickwork & masonry
  • materials technology
  • sustainability

Cite this

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title = "Appropriate structural unfired earth masonry units",
abstract = "Modern earth masonry utilises conventional methods of extruded fired brick manufacturing for the manufacture of unfired earth bricks. However, the bricks produced currently are not generally recommended for structural applications due to their loss of strength under elevated moisture content. In response to this loss in strength, bricks can be chemically stabilised, typically by the addition of cement or lime. However, the use of such binders typically negates the reduced environmental impact of using unfired brick, which is often the initial driver. The research presented in this paper considers the improvement in compressive strength that can be achieved through the addition of a range of pozzolanic binders as well as their associated embodied energy and carbon dioxide. This allows for a holistic comparison of material selection based on meeting the minimum structural requirements of the masonry units, while improving the embodied impact of equivalent units currently used. The study shows that an unfired brick with the addition of lime and metakaolin achieves a compressive strength of more than 6 MPa when dry and more than 1 MPa following complete saturation, while reducing the global warming potential by more than 30{\%}. This paper demonstrates that stabilised unfired bricks can be practically viable, structurally suitable and environmentally beneficial.",
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AU - Heath, Andrew

AU - Walker, Peter

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N2 - Modern earth masonry utilises conventional methods of extruded fired brick manufacturing for the manufacture of unfired earth bricks. However, the bricks produced currently are not generally recommended for structural applications due to their loss of strength under elevated moisture content. In response to this loss in strength, bricks can be chemically stabilised, typically by the addition of cement or lime. However, the use of such binders typically negates the reduced environmental impact of using unfired brick, which is often the initial driver. The research presented in this paper considers the improvement in compressive strength that can be achieved through the addition of a range of pozzolanic binders as well as their associated embodied energy and carbon dioxide. This allows for a holistic comparison of material selection based on meeting the minimum structural requirements of the masonry units, while improving the embodied impact of equivalent units currently used. The study shows that an unfired brick with the addition of lime and metakaolin achieves a compressive strength of more than 6 MPa when dry and more than 1 MPa following complete saturation, while reducing the global warming potential by more than 30%. This paper demonstrates that stabilised unfired bricks can be practically viable, structurally suitable and environmentally beneficial.

AB - Modern earth masonry utilises conventional methods of extruded fired brick manufacturing for the manufacture of unfired earth bricks. However, the bricks produced currently are not generally recommended for structural applications due to their loss of strength under elevated moisture content. In response to this loss in strength, bricks can be chemically stabilised, typically by the addition of cement or lime. However, the use of such binders typically negates the reduced environmental impact of using unfired brick, which is often the initial driver. The research presented in this paper considers the improvement in compressive strength that can be achieved through the addition of a range of pozzolanic binders as well as their associated embodied energy and carbon dioxide. This allows for a holistic comparison of material selection based on meeting the minimum structural requirements of the masonry units, while improving the embodied impact of equivalent units currently used. The study shows that an unfired brick with the addition of lime and metakaolin achieves a compressive strength of more than 6 MPa when dry and more than 1 MPa following complete saturation, while reducing the global warming potential by more than 30%. This paper demonstrates that stabilised unfired bricks can be practically viable, structurally suitable and environmentally beneficial.

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KW - materials technology

KW - sustainability

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JF - Proceedings of the Institution of Civil Engineers: Construction Materials

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