Soluble Salts Amplify the Effect of Small Heterogeneities in the Structure of Porous Building Materials During Drying

• Type: Article in International Scientific Journal
• Date: 2016-08-17

Authors

Ana Sofia Guimarães (Author) FEUP; Diaz Gonçalves, T. (Author) Other; Azevedo, J. (Author) Other

Journal

Title: International Journal of Architectural Heritage

Vol. 10 No. 6

Pages: 766-776

ISSN: 1558-3058

Publisher: Taylor & Francis

Indexing

ISI Web of Knowledge - 1 Citation

Scopus - 2 Citations

Other information

Authenticus ID: P-00K-S1B

DOI: 10.1080/15583058.2015.1118577

Abstract (EN): Salt crystallization is a major cause of degradation in old buildings. One of the issues that stills need clarification is regarding the influence of the salts on the capillary absorption and subsequent drying of porous building materials. This article presents an experimental study that included capillary absorption and evaporative drying tests on two types of material (lime mortar and ceramic brick) using pure water or saturated solutions of six salts (sodium chloride, sodium sulfate, sodium nitrate, sodium carbonate, potassium nitrate, or potassium carbonate). The results of capillary absorption agree only roughly with the linear relationship, predicted by theory, between sorptivity and the square root of the ratio between viscosity ¿ and surface tension ¿ of the solution (¿/¿)1/2. This poor agreement is probably due to material heterogeneity. The drying dynamics was regular and showed little dispersion between specimens, but only for the uncontaminated materials. Indeed, the drying dynamics of the salt contaminated materials was often irregular or diverged among similar specimens, and the same happened with their salt decay patterns. The main conclusion is that soluble salts can amplify the effects on drying of the small structural heterogeneities that porous building materials normally depict. © 2016 Taylor & Francis.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11