Author
A C MAGALHÃES(1), M R VEIGA(1) and F CARTAXO(2)
(1) Buildings Department, Laboratório Nacional de Engenharia Civil (LNEC)
(2) Fradical, fábrica de transformação de cal, Lda.

Abstract
Nowadays, in the rehabilitation of ancient buildings, several special binders and pre-dosed products have appeared as possible solutions for the repair of wall renderings. These rendering solutions must meet functional and aesthetic requirements in order to fulfil the principles of compatibility and to achieve good durability. For this purpose, some characteristics expected to assure compatibility with the walls of ancient building were defined and limits were established for substitution mortars in previous work. In this research, some water repellent lime mortars with pozzolanic and drying additions were characterised in order to evaluate the main aspects of the performance of the renderings and the possibility of their use on ancient walls. The basic binder used for these products is air lime prepared in a special way that assures a certain grade of hydrofugation. The results of the experimental campaign are presented and the mortars’ characteristics are discussed. A comparative analysis of the obtained characteristics for these mortars and for reference mortars analyzed in previous work is presented. Lastly, the compatibility for application on ancient walls is assessed.

Key words
Renders; lime mortars; ancient buildings; requirements; tests