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Cracking Cement and Concrete – Decline of Civil Infrastructure and Heritage. Andrea Hamilton*, Isobel Griffin, Christopher Hall and James Tate Collaborative Research Studentship – Deterioration and Conservation of Historic Concrete Structures: the National Museum of Flight Military Airfield at East Fortune
Figure 1: Cracking – cement render on a shelter at East Fortune.
AHRC/EPSRC SCIENCE & HERITAGE PROGRAMME • SUSTAINING THE IMPACT OF UK SCIENCE AND HERITAGE RESEARCH
Patented in the early 19th Century and popularised in UK construction in the early 20th Century, Portland cement and concrete are by far the most widely employed construction materials worldwide by volume1. Every year nearly 2 billion tonnes of Portland cement is produced worldwide2 and with it 1.6 billion tonnes of CO2, making cement production a significant contributor to greenhouse gas emissions. Consequently there is increasing drive in materials research to improve the ecological credentials of cement by recycling it, using alternative energy sources and using cement to encapsulate industrial waste products1. Concrete is widely used because it is a remarkable and highly versatile material, capable of being tailored chemically, mechanically and aesthetically while cheap and fast setting. Its chameleon-like qualities means that it is also used for high end construction, such as the Burj Dubai skyscraper2. Quite simply, cement and concrete are fundamental to society. Prolonging the life of existing cement and concrete structures will help significantly lower anthropogenic carbon emissions while preserving our built heritage. Although often regarded in the past as ugly, compared to more traditional building materials, many cement and concrete structures are now listed and range from sculptures to factories3 and in this case, a set of utilitarian World War 2 shelters. The conservation of concrete has received very little attention to date, yet the chemical complexity and composite nature of these buildings renders conservation a serious challenge. Prior to any applied conservation efforts, a full understanding
of the deterioration mechanisms of concrete has to be reached. The aim of this PhD project was to use a combination of field surveys, experimental laboratory work and non-destructive testing to understand the cause of deterioration and develop a transferable model. The site is a military airfield in East Lothian, Scotland, with buildings dating from the First and Second World Wars. The Second World War buildings, owned by National Museums Scotland and operated as the National Museum of Flight (NMOF) are collectively a Scheduled Historic Monument. There are 23 cement rendered brick huts and a reinforced concrete air raid shelter.