Contributions to the identification of the systems used to create islamic plasterwork based on the study of decorative elements at the Royal Alcazar of Seville

Abstract

The Royal Alcazar of Seville (hereinafter the "RAS") boasts a very diverse range of plasterwork dating from different periods (14th-16th centuries). This study examines the physical-mechanical properties of the material (porosity, apparent density, water/plaster ratio and surface hardness) conditioned by the construction or execution techniques used, in order to obtain a better understanding of these techniques and to establish a sequence of tests to facilitate the identification of the system that may have been used to produce each element. The aim was to establish a simple methodology to complement historiographical studies and visual inspections in order to evaluate the execution technique used in the creation of the plasterwork. The study of the elements at the RAS can be extrapolated to plasterwork in other similar constructions. The model was based mainly on the establishment of mathematical ratios between the properties to identify the techniques most commonly employed: Carving or modeling and molding. The water/plaster ratio (w/p) used determined the setting time and ranges of values obtained for apparent density (1.38-1.03g/cm3), porosity (41.9-56.5%) and Shore hardness (60-81). It was concluded that hardness, which was the property that provided the most reliable information for identifying the construction system used and its determination, required a non-invasive non-destructive technique. © 2022, University of Cantabria - Building Technology R&D Group. All rights reserved.