Case study Atmospheric deterioration of cement plaster in a building exposed to a urban environment Francesca Tittarelli a, * , Giacomo Moriconi a , Alessandra Bonazza b a Department of Materials and Environmental Engineering and Physic, Universita ` Politecnica delle Marche, Ancona, Italy b National Research Council, Institute ISAC, Bologna, Italy Received 27 March 2007; accepted 6 September 2007 Abstract The work presents results achieved in a research study on the effects of atmospheric deposition on the cement mortar of the basement in a twentieth-century building located in the city of Ancona (Italy). The degree of damage as a function of the sampling depth is evaluated by combining visual observation, scanning electron microscopy, X-ray diffraction, ion chromatography, differential and gravimetric thermal anal- ysis and the quantitative determination of elemental carbon. Sulphation is found to be the main damage mechanism occurring on the cement mortar constituting the base section of a building since the concentration of sulphate increases from the inner to the outer layer at the expense of the carbonate. The absence of sulphite indicates a direct formation of sulphate, possibly due to the catalytic effect of heavy metals present in the carbonaceous particles of the black crust. Insoluble sulphates, such as ettringite, do not form at the surface, but within a deeper layer of the basement due to its instability to atmospheric carbon dioxide. Ó 2008 Elsevier Masson SAS. All rights reserved. Keywords: Atmospheric pollutants; Cement mortar; Plaster deterioration 1. Introduction and research aims Wet and dry deposition of atmospheric pollutants is the main agent responsible for the damage of monuments and his- toric buildings in urban areas. While much has been published to date on the environmental damage on building materials such as stones and bricks, few data are available on the impact of atmospheric pollutants on cement mortars. Cement mortars are found not only in archaeological and historic monuments as restoration materials employed for structural, rendering, re- pointing and consolidation purposes, but also in 19th- and 20th-century buildings, as well as modern structures, which must be considered as an integral part of Cultural Heritage. Today, although clear signs of damage due to atmospheric de- position are also observed on these materials, the scarce information available generally comes from tests performed in the laboratory [1,2]. The aim of this paper is to summarize the results of a re- search study on the effects of atmospheric deposition on ce- ment plaster used in the base section of a modern building exposed to a urban environment, with a view to providing use- ful documentation of degradation phenomena. A synthesis of the characteristics of the collected samples is presented, along with the identification of the damage products forming on the samples as a result of their interaction with atmospheric pollutants. 2. Experimental 2.1. Samples The analysed cement mortars were sampled from the base section of the I.N.C.I.S. building (Fig. 1a) in Ancona (Italy). This building was erected during the twentieth century (1929) according to the typical standards of Fascist architecture. * Corresponding author. E-mail addresses: f.tittarelli@univpm.it (F. Tittarelli), g.moriconi@ univpm.it (G. Moriconi), a.bonazza@isac.cnr.it (A. Bonazza). 1296-2074/$ - see front matter Ó 2008 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.culher.2007.09.005 Available online at www.sciencedirect.com Journal of Cultural Heritage 9 (2008) 203e206 http://france.elsevier.com/direct/CULHER/