The number of listed concrete structures in Scotland is ever increasing and, as these structures age, there is a growing need for their conservation and repair. When repairing concrete structures it is critical to match the properties of the original material as closely as possible. Failure to match the mechanical and chemical properties can not only lead to an unsuccessful repair, but can also cause significant damage and accelerated deterioration to the original material. While some conservators value an ‘honest’ and visible repair, others feel it is important to match the aesthetic characteristics, as this will allow the two materials to blend well visually, retaining the historic character of the structure. However, in order to match these properties it is first necessary to determine both the chemical composition and proportions of the mix constituents. At present, there is very limited data regarding the nature of Portland cement and other constituents in historically-significant concrete structures in the United Kingdom, and that which is available covers a wide geographical area. As the properties of Portland cement and concrete are significantly influenced by the local raw materials and manufacturing processes used in their production, this data does not accurately reflect the nature of early cement and concrete compositions in Scotland. This project aims to resolve such issues by developing a database relating the compositions of cement in concrete structures throughout Scotland to their date, architectural type, production source and physical characteristics, ultimately providing information on past practices and technologies to build up an in-depth understanding of the history of Scottish concrete. Furthermore, there is currently a lack of clear technical guidance or specification with regards to the analysis and repair of historic concrete structures, and the existing standards for analysing hardened concrete are neither accurate nor suitable for use with chemically or physically damaged historic concrete. As such, this thesis discusses the limitations of current analysis methods and questions the extent to which it is possible to accurately evaluate historic concrete using existing methods.
- Concrete durability
- built heritage