Behaviour of brick-NHL render systems in presence of NaCl solution

  • Laura Falchi
  • Laura Speri
  • Eleonora Balliana
  • Martina Zuena
  • Elisabetta Zendri

Resumen

Double-layer renders were formulated for ensuring salt migration, ancient masonries conservation and environmental sustainability. Thus, natural hydraulic lime as binder and recycled aggregates from render wastes were selected. The properties were adjusted by adding an air-entraining agent in the inner layer and different percentages of water-repellent admixtures in the outer layer. The systems were applied on bricks and subjected to rising damp-evaporation cycles, for investigating their behaviour and properties in respect to NaCl migration. Mono-material prismatic render specimens were also studied. Water vapour permeability, capillary absorption, drying behaviour, compressive strength, mechanical resistance, conductivity and porosity of each formulation were evaluated. Good durability was observed whenever the render layers had different microstructure, either there was salts deposition within the lower layer,or if there was tefflorescences formation. If the layers had similar structure, deposition of salt at the brick-render interface occurred causing damages to the substrate.

Biografía del autor

Laura Falchi

Laura Falchi, Ph.D. in Chemical Sciences, conservator scientist. 2010- Graduated in “Chemical Sciences for the Conservation and Restoration” at the Ca´ Foscari University of Venice with the thesis “ Chemical-physical study of consolidants based on water-borne acrylic emulsions and colloidal silica emulsions for historical mortars”. 2010-2011, Internship and working experience in the research product departments of the San Marco Group S.p.A., Volteco S.p.A, VENETO NANOTECH S.C.p.A; 2012, internship at the Federal Institute for Materials Research and Testing (BAM, Berlin); 2013 science teaching at the secondary school. 2013 Ph. Doctorate in “Chemical Science” at Ca´ Foscari with the topic “ Study of Water-Repellent Systems for the Protection and Maintenance of Mortars”. Since 2014, fellow researcher at Ca’ Foscari University of Venice in the “Chemistry for the Conservation of Cultural heritage Group”. I have been working for the characterization of acrylic emulsion, colloidal silica, and epoxy resins suitable as consolidants for stone materials. My actual research topics includes the study of architectonical surfaces in Venice area also in relation with the environment and the climate changes, development of techniques and products for the protection of historic masonries.

Laura Speri

Laura Speri is a conservator scientist. Graduated in “Chemical Sciences for Conservation and Restoration” (Master Degree) in 2016 at Ca’ Foscari University of Venice with the thesis “Formulation and study of the behaviour of repairing renders by experimental evolutionary design” . Her research interests include artificial stone investigation and formulation, experimental design.

Eleonora Balliana

Graduated in Chemical Sciences and Technologies for Conservation and Restoration at Ca’ Foscari University of Venice in 2007. From 2009 researcher in the sector of CHIM/12 (Environmental and Cultural Heritage Chemistry) at Ca’ Foscari University and professor of the Laboratory of Conservation for the third year of the Master in Technologies for the Conservation and the Restoration of Cultural Heritage. Main fields of interest: materials characterization and investigation in art; architectural surfaces; natural and artificial stone materials; investigation on relationship between environment and material degradation processes; monitoring methods for outdoor surface characterization and preventive conservation; development of new products and applications for cultural heritage.

Martina Zuena

Master Degree (2014) in “Science and Technology for the Conservation of Cultural Heritage”, La Sapienza University of Rome with the thesis “Evaluation of mechanical properties of hydraulic binders modified with basalt fibers”. Now, she is attending the PhD in Chemical Science under the joint supervision of Ca’ Foscari University of Venice and University of Trieste with the project “Study of calcium alkoxides as a new conservation product for consolidation of historical limestone”. From September 2016 to January 2017 she worked in Lisbon at the LNEC - Laboratório Nacional de Engenharia Civil - for an internship period.

Elisabetta Zendri

Associate Professor at the University of Ca’ Foscari since 2001. She is the Coordinator of the research group “Chemical Sciences for the Conservation of Cultural Heritage” and Coordinator of the Master Degree  in “Conservation Science and Technology for Cultural Heritage” at the Ca’ Foscari Univerity of Venice. She was responsible in research projects in the field of Conservation of Cultural Heritage promoted by the Italian Ministry of Education, in Interreg  Programme IT-SLO “Shared Culture”. She is coordinator of Research Unit in the JPI-EU project EMERISDA “Effectiveness of methods against rising damp in buildings: European practice and perspective” and in the project “VoicesOfVenice “ FP7- PEOPLE-2013-IOF (Marie Curie Action). The research activity is developed in collaboration with national and international Universities and Institutions. The research activities deal in particular on: new technologies and methods for the conservation and restoration of Cultural Heritage assets; Characterization and preservation of archaeological and traditional building materials (mortar, brick, plaster, stone, pottery); Investigation and conservation protocols for the modern and contemporary mural paintings. She has collaborated and collaborates in several projects for the restoration of important monuments in Italy and abroad. She attend many National and International Congress and she has published more than 150 publications on national and international journals and authors of books chapters. She is member of Scientific Committeee of the International association “Scienze e Beni Culturali”.

Publicado
2017-06-30
Cómo citar éste artículo
FALCHI, Laura et al. Behaviour of brick-NHL render systems in presence of NaCl solution. Ge-conservación, [S.l.], v. 1, n. 11, p. 157-164, jun. 2017. ISSN 1989-8568. Disponible en: <http://ge-iic.com/ojs/index.php/revista/article/view/468>. Fecha de acceso: 21 sep. 2017

Palabras clave

Render; double-layer systems; salt transport; brick; rising damp

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