Electrochemical Methods For The Preservation Of Masonry Clad Structural Frames
Free (open access)
P. Lambert & Y.-Y. Wu
A large number of historic structures incorporate wrought iron or early steel components within the masonry. Generally, these were incorporated at the time of construction or in later refurbishments to enhance the structural integrity or fire resistance of the buildings. With time, and in the presence of moisture and oxygen, the ferrous component starts to corrode and the voluminous corrosion products cause cracking and spalling of the surrounding masonry. The traditional method of dealing with such problems has been to remove the affected masonry and treat or replace the corroded metalwork prior to reinstatement. This is not only expensive, but involves the removal of large amounts of the original masonry, which may have to be replaced with modern equivalents. A more effective and sensitive option is available through the use of electrochemical treatments, specifically cathodic protection which was originally developed by Sir Humphry Davy in the early 19 th century for the preservation of naval vessels. This paper discusses the development of this technology from early naval trials to recent development for use on heritage buildings and introduces the numerical methods for modelling of cathodic protection systems that assist in the design optimisation of such systems for protecting historically sensitive structures with the minimum of physical disruption. A number of existing and developing electrochemical approaches to corrosion control are also discussed. This work is being undertaken at the Centre for Infrastructure Management, Sheffield Hallam University with support from the Royal Society. Keywords: corrosion, masonry, steel frame, cathodic protection, galvanic or sacrificial anodes, impressed current, numerical modelling. 1 Introduction The identification of "Regent Street Disease" in the United Kingdom in the late 1970's highlighted the problems of the corrosion of iron and steel frames and
corrosion, masonry, steel frame, cathodic protection, galvanic or sacrificial anodes, impressed current, numerical modelling.