Introduction
Adobe (mud or clay) bricks have been a construction material for at least five thousand years. A readily available resource in many arid and semi-arid regions, adobe structures offer protection from the heat of the day and insulate against cold temperatures at night. The structural integrity and durability of such structures has been call for concern and modern building methods involving fired bricks have become the mainstay of the construction industry. However, the firing of bricks consumes large quantities of energy; for example, in the UK It has been estimated that the energy needed to manufacture 12 bricks takes the equivalent to 1 gallon (4.5 litres) of petrol. Such energy use is unsustainable and there is a pressing need to find alternatives to fired bricks.
This research is supported by The British Council, the Institute for Environment, Sustainability and Regeneration (Staffordshire University, UK), ENIS (University of Sfax, Tunisia) and Groupe Chimique Tunisien (Sfax, Tunisia).
For more information about this project please contact:
Prof. Mike Anderson, Faculty of Computing, Engineering and Technology, Staffordshire
University.
Email: m.anderson@staffs.ac.uk
Summary of project research
A new research project has arisen out of long-standing relationship between Staffordshire University and the University of Sfax in Tunisia. This research focuses on two major problem wastes found within the vicinity of the city of Sfax, both of which are environmentally hazardous to health. The intention is to incorporate quantities of both in an ‘adobe’ style building block to empirically demonstrate this as a practical route to commercial manufacture and utilisation. Although the basic ingredient will be local clay, it is intended to blend this with a suitable proportion of olive oil effluent (margine) as a plasticiser and phosphogypsum as a structural component. This targeted fabrication route represents a technical innovation over long-established (traditional) adobe bricks made of 100% clay, as the incorporation of these wastes should also create enhanced product performance in terms of greater strength and improved weathering properties. Apart from the crucial advantage of a major reduction in the energy used carbon footprint when compared with equivalent (fired) clay products, it is also anticipated that the new Tunisian product will possess additional environmental benefits, most notably, a low thermal conductivity (arising from the clay microstructure). This will provide advantageous energy payback when used in the construction of domestic dwellings in hot dry climates i.e. a cool interior during the day and increased warmth at night when the day stored heat is released, thus minimising the need for conventional air-conditioning.
This project demonstrates Tunisia’s increasing awareness of sustainability
and commitment to tackling environmental issues by using ‘green’ solutions
in the context of the built environment. Group Chimique Tunisien (GCT),
a major state-owned phosphate production company in Sfax, are supporting
the project through the provision of phosphogypsum for inclusion in the
experimental unfired bricks. Margine and clay have also been locally sourced
at sites in close proximity near Agareb, west of Sfax. Elements of the experimental
work will take place at Staffordshire University under the direction of
Prof. Mike Anderson, Dr. Janet Wright and Prof. Fiona Tweed. The École Nationale
D’Ingénieurs de Sfax (ENIS) at the University of Sfax will carry out experimental
work under the direction of Dr. Emna Ammar and Dr. Houda Mekki.
It is envisaged that this will be a two phase project. The first phase will
concentrate on the identification and development of potential prototype
unfired products and their testing, the goal being to achieve a robust and
potentially commercially acceptable product. The second phase will involve
the production of a batch of full-sized units to be used in the erection
of an appropriate sized building structure. This will be used to provide
a test-bed for detailed instrumental monitoring.
Project impact
It is anticipated that the outcome results recorded will establish the beneficial advantages of this new low-cost and sustainable building product and confirm its suitability for future commercial production within Tunisia. We anticipate that, on publication of the results, the potential of this product will be recognised by trade and industry and it is hoped that the Tunisian Government will assist this enterprise into its entrance into the commercial marketplace.
Project reports