Porosity and surface hardness as indicators of the state of conservation of Mudejar plasterwork in the Real Alcazar in Seville

Abstract

Plasterwork, a very typical element of Islamic art, comprises highly artistic decorative elements on wall, arches, and vaults. Due to their gypsum composition, such elements are easily weathered, primarily because of low mechanical strength and slight solubility in water. This work has studied the traditional Islamic plasterwork in the halls and patios of the Mudéjar Palace (13–16th centuries) in the Real Alcázar of Seville. This palace complex was declared a World Heritage Site by UNESCO in 1987. The analysis of its porosity and shore C surface hardness has allowed determination of the mathematical correlation between them. Consequently, future evaluations can merely measure the hardness (a non-destructive test) to estimate the plasterwork’s porosity (which reveals its mechanical strength and its degree of weathering). These elementsmust bemaintained inorder topreventthe spread ofpathologies.Inaddition to requiring an in-depth knowledge of its materials, application techniques, and properties, to do so also demands simple techniques for regular assessments and criteria to prioritize interventions ifthey become necessary