Abstract:
The Fort of Nossa Senhora da Graça is located in a mountain at north of the
town of Elvas. It was built in the late 18th century at the order of King Joseph I of Portugal
and the Marquis of Pombal. It was built by Count Lippe, and listed as a National Heritage
Site in 1910 and a World Heritage Site by UNESCO in 2012 together with other
fortifications present in Elvas. As part of its nomination by UNESCO, a conservation and
restoration plan has been implemented involving a detailed characterization of materials
used in its construction. To support the restoration project, a comprehensive analytical
study was implemented. In this paper the main results of the characterization of a group of
the existent mortars are presented. The mortars are, in general, in very good condition,
being composed of aerial dolomitic lime with siliceous aggregates (from igneous and
metamorphic rocks). The mortars conservation and restoration works were performed with
compatible repair materials, selected according to the physical-chemical characterization
and on the evaluation of the conservation state.