Analysis of the materials and state of conservation of the medieval rammed earth walls of Seville (Spain)

Abstract

In the specific study of medieval fortifications, an advanced knowledge of the state of conservation is required to achieve an effective diagnosis and a detailed evaluation that will provide the basis for establishing the criteria for prevention and restoration. The characterization of the materials and the knowledge of their degree of deterioration is one of the key points to address a restoration project in any rammed earth wall. In the last decades, a number of medieval fortifications built with rammed earth in Spain have been studied and restored. Although there is currently a better knowledge of the construction materials involved and their degradation processes, no detailed work has been carried out to date on the Seville City Wall, which is an outstanding sample of this kind of heritage. The aim of this work is hence to study the material characterization of the most recognisable section of the whole structure, which is known as Macarena Wall, that runs between the Macarena and the Cordoba Gates. The results and discussions presented offer a novel approach for this heritage asset and would play a solid criterion for a correct restoration proposal. For this purpose, ananalytical methodology already known and verified in the literature has been followed, which has been adapted according to the specific requirements of this monumental building. Among the most relevant results of the analytical and experimental phase, it is highlighted that capillary humidity and the transport and crystallisation of salts is one of the main causes of the deterioration of this monument. As this building is a clear reference of rammed earth military structures, the analytical procedure and the results obtained are an interesting reference for other similar interventions. © 2021 The Authors