MATOS MARGARIDA1, BORSOI GIOVANNI2, VEIGA ROSÁRIO3, FARIA PAULINA4, SANTOS-SILVA ANTÓNIO5

1) MSc, NOVA University of Lisbon, Department of Civil Engineering, md.matos@campus.fct.unl.pt

2) PhD student, Technical University of Delft, Faculty of Architecture, G.Borsoi@tudelft.nl

3) Senior Researcher, National Laboratory for Civil Engineering, Buildings Department, rveiga@lnec.pt

4) Associate Professor, UNIC, NOVA University of Lisbon, Department of Civil Engineering, paulina.faria@fct.unl.pt

5) Research Officer, National Laboratory for Civil Engineering, Materials Department, ssilva@lnec.pt

A common degradation phenomenon in historical renders is the cohesion loss of the binder:aggregate system, which is often linked to the presence of soluble salts. Cohesion is recovered through the application of consolidant products, being inorganics preferred due to their compatibility and durability. The aesthetic function can be restored by chromatic reintegration.

The aim of this paper is the assessment of the durability of consolidation and chromatic reintegration treatments applied on renders when exposed to marine environment.

Mortar specimens with a simulated loss of cohesion were consolidated with commercial nanolimes, which were considered due to their stability and compatibility. Their combined application with ethyl silicate guarantees some benefits. Chromatic reintegration treatments were obtained by mixing pigments in the consolidant products. After treatments, dissolution-crystallization cycles were performed with a sodium chloride solution.

Consolidation effects were monitored. Physical characterization was performed on specimens before and after contamination and the results were discussed.

Keywords: Historical renders, consolidation, nanostructured products, chromatic reintegration, salt crystallization cycles