The corrosion of early 20th century steel-framed buildings is resulting in serious damage to the integrity and appearance of many historically important structures. Since the application of cathodic protection to steel framed buildings in the late 1990s it has been proven to provide a low intrusive and aesthetically acceptable technique for the conservation of heritage structures.The principles of cathodic protection have not changed since its discovery by Humphry Davy in 1824 but have been adapted to a wide range of structures over the subsequent 190 years. The systems itself have been refined and improved over time except in the case of steel framed buildings where it is still in its early years. This paper discusses the application of an innovative cathodic protection system on steel framed buildings that utilises a geopolymer with admixed carbon fibres. The system does not require the installation of additional discreet anodes and is in the form of a repointing mortar in the joints of the cladding from where it is able to provide protection. The principles of the system and its first commercial application are presented.
Concrete has been used as a construction material for several thousand years. The concrete as known today was only developed around 150 years ago after the technology was all but lost for a millennium after the fall of the Roman Empire. Historic concrete structures therefore generally only date back second half of the 18 th century. Structures that date further back are considered to be ancient concrete. The structures that require attention and therefore an assessment generally belong to the more recent period.Concrete can be a very durable construction material and it was initially thought that it could essentially last forever, however, this has subsequently been proven to be wrong. Concrete can deteriorate as a result of structural inadequacies and due to chemical interactions between the concrete constituents, external aggressants and the embedded steel reinforcement. The deterioration patterns vary from purely cosmetic cracking, cracks affecting the structural integrity, ineffective protection against reinforcement corrosion and loss of steel cross sectional area.This paper provides an overview of many of the different types of deterioration that can be encountered in historic concrete structures and how the cause and severity can be assessed using different investigative techniques.
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