Rammed earth research

I have recently completed a PhD at the University of Durham. This research looked at the fundamentals of rammed earth construction and the analysis and repair of historic rammed earth buildings.

PhD - Analysis of historic rammed earth construction

Analysis of historic rammed earth construction

My PhD looked at how best to understand and preserve historic rammed earth structures. This was done by considering the fundamental forces which bind rammed earth, and showing that the surface tension of water may be responsible for the increased strength and stiffness of earth buildings. This insight led to a better understanding the structural behaviour of rammed earth and other earth buildings.

Much of the work has been presented at international conferences, or has appeared in refereed journals. For full details, see publications

Rammed earth sites

During the course of my PhD, and following the research, I have visited a number of historic rammed earth sites around the world.

Rammed earth in Ladakh, India and Marakesh, Morocco

Seismic behaviour of earth buildings

Current guidelines for the seismic design of unreinforced earth buildings are based on very simple rules and a small amount of dubious testing. Nevertheless, such guidelines are routinely used by many international NGOs. There is weath of work carried out in the Spanish speaking world on the aseismic reinforcement of earth buildings, but to date there appears to be little work carried out into the behaviour of unprotected earth buildings. This work aimed to review the behaviour of fired and unfired clay bricks to compare their behaviour.

Seismic behaviour of earth buildings

Quarter scale earth brick wall on the BLADE shaking table at Bristol University

Research opportunities

During the course of my PhD I identified many further areas of research which I feel should be investigated. In particular I have identified areas which may now be better investigated following the discoveries made during my PhD.

These areas include:

• Determination of peak cement content for earthen building
• Unfired clay brick mortars
• Rates of decay in historic rammed earth structures
• Compaction optimum moisture content
• Review of existing UK rammed earth projects
• Wall top coverings
• Structural rammed earth
• Repair methods for damaged historic earth buildings
• Seismic loading
• Relative humidity in earthen buildings
• Fly ash in rammed earth
• Urine mud bricks

I have worked with Engineers without Borders and have prepared a document giving details of these and other projects.

These projects would particularly suit university final year engineering projects. If you are interested in these or similar projects, please contact me.

International research

Research at Durham University is continuing under Dr Charles Augarde and details can be found on the Earthen construction @ Durham University web pages.

For details of current research into earthen construction, see the research links page or go to Research.Terra where we are attempting to complile information about all the research recently undertaken into earth building.