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University of Pennsylvania (2000)

Study of Deterioration Mechanisms and Protective Treatments for the Egyptian Limestone of the Ayyubid City Wall of Cairo

Bourguignon Elsa Sophie Odile

Titre : Study of Deterioration Mechanisms and Protective Treatments for the Egyptian Limestone of the Ayyubid City Wall of Cairo

Auteur : Bourguignon Elsa Sophie Odile

Université de soutenance  : University of Pennsylvania

Grade : Master of Science (MS) 2000

Résumé partiel
The al-Azhar project of the Aga Kahn Trust for Culture will create one of the largest urban parks in Cairo. This has brought attention to the eastern portion of the Ayyubid city wall which would border the western edge of the park. Partially buried during centuries, the stone wall presents different forms of deterioration, including flaking and disaggregation as well as large areas of salt crusts on the stone surface requiring a comprehensive conservation treatment. After a brief history of the fortifications of the city of Cairo including previous interventions on the eastern section of the fortifications, this work presents a review of the literature on Egyptian limestone since this was the stone used in the wall construction. This stone contains an unusually high concentration of salts but only a relatively low concentration of clay minerals. An overview of the literature on deterioration mechanisms shows that the daily variations in relative humidity and temperature, particularly important in the arid climate of Cairo, cause both cyclic swelling of the clays and crystallization the salts. Furthermore several examples highlight that a synergy exists between the deterioration caused by the salts and that due to the clay minerals, the presence of one exacerbating the deterioration caused by the other. These processes contribute to the deterioration of this moderately resistant limestone, and are ultimately detrimental to integrity of the masonry.

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Page publiée le 11 juin 2021