University of Bologna, ITALY, DICAM Department
University of Sao Paulo, Brazil, Structural Engineering Dept.

The exposure to environmental actions produces several degradation patterns in masonry texture, mainly as a function of the chemical reactivity of the masonry materials. Blistering of the bricks and powdering of the mortar can reduce locally the thickness of structural elements and introduce eccentricity of the thrust path. In the paper, the results of a preliminary analysis of a typical degradation and repair situations is presented. By comparing existing experimental data with site data it is possible to link the salt concentration, humidity and ambient temperature variation with the rate of pulverization of brick faces and mortar decay. The role of initial porosity is pointed out and some data on the increase in porosity due to salt attack are useful to define an analytical relationship among parameters. Finally, two examples of site investigations in Venice and Ancona sea front zones are presented in order to highlight the role of rheological properties and weather conditions as driving factors of the observed decay patterns.

Key words
Masonry, degradation, mechanical properties, salt attack, rehabilitation