The Angera stone: a challenging conservation issue in the polluted environment of Milan (Italy)

Gulotta, Davide; Bertoldi, Margherita; Bortolotto, Susanna; Fermo, P.; Piazzalunga, A.; Toniolo, Lucia

doi:10.1007/s12665-012-2165-2

Cited by 52 publications

(42 citation statements)

References 19 publications

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“…The occurrence of calcium oxalate is generally due to the partial oxidation of organic carbon (Rampazzi et al, 2005;Sabbioni and Zappia, 1991) that could come from organic protective products applied during previous restoration work, or from the activity of microorganism colonies, or from pollutants (Barone et al, 2008;Belfiore et al, 2010;Gulotta et al, 2013). When the sampling phases were carried out, these monuments, according to the documentation, had not undergone any past restoration, so it is reasonable to identify the environmental pollutants or biological colonization, as the agents responsible for the formation of calcium oxalate.…”

Section: Discussionmentioning

confidence: 99%

An analysis of the black crusts from the Seville Cathedral: A challenge to deepen the understanding of the relationships among microstructure, microchemical features and pollution sources

Ruffolo

Comite

Russa

et al. 2015

Science of The Total Environment

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Section: Discussionmentioning

confidence: 99%

An analysis of the black crusts from the Seville Cathedral: A challenge to deepen the understanding of the relationships among microstructure, microchemical features and pollution sources

Ruffolo

Comite

Russa

et al. 2015

Science of The Total Environment

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“…Further, with the aim to evaluate the protective action of the applied coatings, the substrates (bare stones and treated by both Si-based resins) were exposed in parallel in two typical urban environments placed in Milan and characterized by different conditions as concerns the impact of the main atmospheric pollutants (Gulotta et al 2013;Fermo et al 2014b). The first one is placed in the Milan University Campus (Fig.…”

Section: Ageing and Ambient Exposure Testsmentioning

confidence: 99%

On the role of hydrophobic Si-based protective coatings in limiting mortar deterioration

Cappelletti

Fermo

Pino

et al. 2015

Environ Sci Pollut Res

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In order to avoid both natural and artificial stone decay, mainly due to the interaction with atmospheric pollutants (both gases such as NOx and SO2 and particulate matter), polymeric materials have been widely studied as protective coatings enable to limit the penetration of fluids into the bulk material. In the current work, an air hardening calcic lime mortar (ALM) and a natural hydraulic lime mortar (HLM) were used as substrates, and commercially available Si-based resins (Alpha®SI30 and Silres®BS16) were adopted as protective agents to give hydrophobicity features to the artificial stones. Surface properties of coatings and their performance as hydrophobic agents were studied using different techniques such as contact angle measurements, capillary absorption test, mercury intrusion porosimetry, surface free energy, colorimetric measurements and water vapour permeability tests. Finally, some exposure tests to UV radiation and to real polluted atmospheric environments (a city centre and an urban background site) were carried out during a wintertime period (when the concentrations of the main atmospheric pollutants are higher) in order to study the durability of the coating systems applied. The effectiveness of the two commercial resins in reducing salt formation (sulphate and nitrate), induced by the interaction of the mortars with the atmospheric pollutants, was demonstrated in the case of the HLM mortar. Graphical Abstract ᅟ.

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“…This latter aspect further threatens marble durability, because, through the newly developed micro-cracks, clean and acid rainwater, salts-rich rising damp, as well as atmospheric gaseous pollutants, can penetrate into marble, thus worsening the related weathering phenomena (e.g., calcite dissolution, gypsum formation and salt crystallization) [5,7,[10][11][12][13]. Moreover, in the presence of moisture and/or liquid water, thermal weathering itself is accelerated, because, upon heating, water exerts a pressure against capillary pores, resulting in tensile stress inside marble [2,9,10,14,15].…”

Section: Causes and Consequences Of Marble Sugaringmentioning

confidence: 99%

Sugaring marble in the Monumental Cemetery in Bologna (Italy): characterization of naturally and artificially weathered samples and first results of consolidation by hydroxyapatite

Sassoni

Franzoni

2014

Appl. Phys. A

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The so-called sugaring of marble is a very common degradation phenomenon, affecting both historical monuments and modern buildings, which is originated by environmental temperature fluctuations. Thermal cycles are indeed responsible for micro-cracks formation at the boundaries between calcite grains, so that marble is subjected to granular disintegration and can be reduced to a sugar-like powder of isolated calcite grains by just the pressure of a finger. Since no effective, compatible and durable treatment for sugaring marble consolidation is currently available, in this paper a novel consolidating treatment recently proposed for limestone, based on the formation of hydroxyapatite inside the stone, was investigated for weathered marble. To test the new treatment on suitably decayed marble samples, some naturally sugaring marbles from the Monumental Cemetery in Bologna (Italy, nineteenth century) were firstly characterized by scanning electron microscope (SEM), mercury intrusion porosimetry (MIP) and ultrasonic pulse velocity (UPV) measurement. Then, artificially weathered samples were produced by heating fresh Carrara marble samples at 400°C for 1 h. The effects of artificial weathering were characterized using the same techniques as above, and a very good agreement was found between microstructure and mechanical features of naturally and artificially weathered samples. Then, the hydroxyapatite-based treatment was tested on the so-obtained artificially weathered samples, and the treatment effects were characterized by UPV, MIP and SEM equipped with energy dispersive spectrometry and Fourier transform infrared spectroscopy. The hydroxyapatite-based treatment exhibited a remarkable ability of restoring marble cohesion and a good compatibility in terms of modifications in pore size distribution, which leads to regard this treatment as a very promising consolidant for weathered marble.

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The Angera stone: a challenging conservation issue in the polluted environment of Milan (Italy)

Cited by 52 publications

References 19 publications

An analysis of the black crusts from the Seville Cathedral: A challenge to deepen the understanding of the relationships among microstructure, microchemical features and pollution sources

An analysis of the black crusts from the Seville Cathedral: A challenge to deepen the understanding of the relationships among microstructure, microchemical features and pollution sources

On the role of hydrophobic Si-based protective coatings in limiting mortar deterioration

Sugaring marble in the Monumental Cemetery in Bologna (Italy): characterization of naturally and artificially weathered samples and first results of consolidation by hydroxyapatite

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