Coating with nanostructured Titanium dioxide is able to enhance natural stone surface with self-cleaning and depolluting abilities; nonetheless, the durability of the coatings is a crucial issue to be assessed in relation to their potential for use in the context of the building heritage. In this paper, the resistance of coatings applied on a compact and a soft limestone, which differ in roughness, porosity and cohesion features, has been investigated. A peeling and a water impact test were performed and their effect on the coated surface was evaluated as film loss by qualitative/quantitative ESEM-EDS analyses. Self-cleaning effectiveness was assessed by performing a photodegradation test of Rhodamine B. Crack-free and conformable films showed a good anchorage to both limestones; after the durability tests the coated surfaces exhibited almost unchanged Ti/Ca ratios and self-cleaning efficiencies. Large adhesion failures and decreased Ti amounts were recorded where coatings were fissured; they especially occurred on the surface of the compact limestone, along with a reduced self-cleaning ability. High surface roughness accounted for a better adhesion of both crack-free and fissured films to the soft limestone, but some erosion of the coated surface, which affected this friable stone under the water impact, compromised their preservation. Nonetheless, good self-cleaning performances were still provided due to the retention of nanoparticles under the surface.The overall results support that preservation of nanostructured TiO2 coatings on the stone surface depends on the inherent characteristics of both films and supports; durability of the stone itself can play an important role.

Titanium dioxide based nanocomposites for stone coating have been found to be promising in laboratory conditions to obtain manifold protective actions against pollution and weathering affecting the outdoor built heritage. Lasting performances in real conditions of these multifunctional coatings have been scarcely examined, although this is a key issue in evaluating their potential for applications in a real building context and their optimization. This paper illustrates a field study aimed at investigating simultaneous hydrophobic and self-cleaning effectiveness, on the medium-long run, of TiO2 NPs/fluoropolymer coatings applied on a limestone. The samples coated with the nanocomposites were exposed for one year in an urban environment and their surface was monitored. Hydrophobic properties were checked through contact angle measurements and a capillary water absorption test, while self-cleaning efficiency was evaluated by a photodegradation test of Rhodamine B. Optical microscopy observations and colour measurements were also performed. In addition, the contents of Ti and water-soluble ions on the sample surfaces were determined by X-ray Fluorescence and ion chromatography, respectively. The overall findings showed that TiO2 NPs did not affect the ability of the polymer to protect the stone surface against water penetration. The coatings were able to preserve the surfaces from dirt. However, photocatalytic efficiency progressively decreased, due to the loss of the photocatalyst from the coating surface, which may be attributed to a polymer modification by ageing. The embedding of nanosized titania within the polymer limited the adsorption and accumulation of soluble salt ions on the coated surface, which may increase the stone damage risk.

The debate on graphic vandalism is recent in Italy and there are few comprehensive studies on this subject. The graffitism isnot only an aesthetic damage but a serious and irreversible degradation of the stone, by altering its state of preservation in airreversible way. This work approaches the graphic vandalism by following two routes: a) the micro analytical study of theinteraction of spray varnishes with some stone samples (obtained from Ragusa and Palazzolo (Sicily) lythothypes) and withreal stone samples (coming from historical buildings sited in Ortigia-Syracuse); b) the testing of the effectiveness andefficiency of some commercial products used to remove the varnish constituents from some stone specimens, by checking thepresence of residues onto the analyzed surfaces. In both cases, several micro analytical techniques were used.

Graffiti on facades often has a heavy impact in social and economic terms, particularly when historical and artistic artefacts are affected. To limit the damages to the surfaces, preventive plans are implemented and anti-graffiti coatings are used as a protective measure. In this study, the distribution of a spray paint inside a highly porous stone, with and without anti-graffiti protection, was investigated. Two commercial sacrificial anti-graffiti systems were used and an acrylic-based paint was applied as staining agent. Environmental scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS) microanalysis were performed to characterise, from the morphological and chemical point of view, the anti-graffiti coatings and the paint. Maps of the main elements were acquired to locate the different products inside the stone. Chemical removers were used to clean the stained surfaces, then the effectiveness of the cleaning was assessed by visual observations and colour measurements, as well as on the basis of percentage of residual stain. The obtained results highlighted that the anti-graffiti efficacy strongly depended on the characteristics of the applied coating. This latter usually acted as a barrier, but good results were obtained only where the stain did not remain as a separate layer, but penetrated the protective coating. Microcracks in the anti-graffiti coating were able to ify the protective action.

The paper describes the multidisciplinary research carried out on the Church of Santo Stefano in Soleto (Lecce, Italy) by IN-Cul.Tu.Re. Project (INnovation in CULture, TUrism and REstoration) supported by lbam-Cnr Institute of Lecce, the Politecnico of Torino "Non Destructive Diagnostic Laboratory" and the exSoprintendenza Beni Storici, Artistici ed Etnoantropologici of the region of Puglia.The latest restoration of the Church of S.Stefano, one of the most significant examples of late Gothic painting in the region of Puglia, was realized in 2012. This study aimed to increase the knowledge and the enhancement of the Church through: historical and documentary study; analysis of the past restoration projects and diagnostic tests; new non-invasive diagnostic testing; ICT. A Semi-ARplatform was developed as a tool for the Church protection, conservation and enhancement: a 3D model was exploited as a support for information about paintings iconographic analysis and techniques, virtual restoration and for the results of the latest diagnostic surveys. This platform and non-invasive diagnostic tests allow to monitor the conservation conditions and to map the degradationphenomena. The research analyzes the relationship between heresy and orthodoxy in the choice of the method and also in the (real/virtual) visit of cultural heritage. The Project, winner of the competition announcement Smart Cities and Communities and Social Innovation, was founded by Miur.

Natural stones with self-cleaning and depolluting abilities are appealing to preserve building façades in polluted urban sites and simultaneously to provide air-purification. Coating with photocatalytic Titanium dioxide is promising at this purpose; nonetheless, stone coating issues need better insights to support large-scale applications. In this paper, photocatalytic surfaces of two limestones having different roughnessess and porosities, are investigated by comparing coatings obtained from either water and alcohol based colloidal suspensions of TiO2 nanoparticles, which were synthetized by sol gel and hydrothermal process and sprayed with different loads on the stone surface. A commercial water-based TiO2 sol was also used. The study aims to assess the role of the substrates, the nature of the titania dispersions and the TiO2 loads, in determining characteristics and properties of the photocatalytic stone surfaces, in order to obtain suited coatings for real applications on buildings. Colorimetry detected negligible colour changes on both stone surfaces due to the coatings. A photodegradation test of Rhodamine B recorded a high self-cleaning efficiency on the coated surfaces, irrespective of the stones, the alcohol and water based suspensions, and their TiO2 loads. Conversely, the efficiency in a NOx abatement test was dependent on the porosity and roughness of the stones. ESEM-EDS on the applied coatings and XRD on the TiO2 nanopowders identified critical issues in the coating morphology and presence of by-products relating to the preparation of the sols, which may have implications in the durability performances.The overall results showed that all the obtained coatings were able to deliver photocatalytic surface of both limestones, which have a potential to be implemented as eco-efficient materials on buildings. Nonetheless, higher air purification ability issued for the limestone with higher porosity and roughness and the experimental TiO2 water-based sol performed better than the alcoholic and commercial ones as regards the coating morphology and absence of by-products.

The Petruzzelli Theatre in Bari (Southern Italy) is an important example of a nineteenth century "Politeama" (i.e. a venue intended for various forms of live entertainment) which was inaugurated in 1903. It was decorated with stucco elements, consisting of mouldings and decorations in greater or lesser relief present on the ceilings and walls, and on statues. In 1991 the Theatre was struck by a fire, which caused serious damage to the main auditorium, whose furnishings and roof were almost completely destroyed; the foyer was less badly affected, and a large part of the decorations (stucco, papier-mâché and wood) on the walls and ceilings remained apparently intact.On site examination by naked eye detected diverse forms of damage to the decorations ; both extensive blackening due to the presence of combustion deposits, and superficial "roasting", crumbling, cracks and separation of the stuccoes from the wall were observed in the areas affected by the flames. In contrast, in the areas furthest from the heart of the fire the damage appears to be basically due to the effect of high temperature fumes, with the presence of combustion deposits, underneath which the material seems intact.The present study aims at the characterization of the constituent materials and the painted surface decorations, as well as ascertaining the effects of the fire.It was carried out on the samples from the surviving parts of the stage-box decorations, directly affected by the fire, and on those present inside the foyer, affected by the fire to varying degrees. These stuccoes were compared with samples not affected by the fire, that were taken from rooms next to the Theatre.The composition and structure of the stuccoes and modifications related to the fire effect were investigated by Optical microscopy in transmitted and reflected light (LM) and ESEM, as well as by combined analytical techniques such as EDX DRX, FT-IR and DTA-TGA.The combined microscopic observations and analyses pointed out different types of stuccoes in terms of mineralogical-petrograhical composition. The effects of the fire action were identified in the formation of some new mineralogical phases, coming from the de-hydration of the gypsum binder, as well as from the mineral pigments used in the painted layers. Their presence allowed determining the different temperatures that were locally reached during the fire.Damage in the forms of microcracks affecting the stucco groundmass, detachments and melting of the superficial finishings were also observed, as well as micro-blisters likely due to the burning of the oil binder.

This paper reports a study of the effects of fire on the decorative stucco elements consisting of painted mouldings and decorations in the Petruzzelli Theatre in Bari (Southern Italy). The theatre was built at the end of the nineteenth century. In 1991 a fire caused serious damage to both materials and structure.Visible damage to the decorations included various deterioration patterns. The fire-related effects on both plaster and painted surface layers were subjected to in-depth investigation under laboratory conditions by focusing on mineralogical, chemical and microstructural alterations. Methods used included Optical Microscopy, Environmental Scanning Electron Microscopy coupled with X-ray microanalysis, X-ray Diffraction, Fourier transform infrared spectroscopy and simultaneous Thermogravimetry-Differential Scanning Calorimetry.De-hydration of the gypsum binder and oxidation of the iron compounds caused new mineralogical phases to form in the stucco plaster. In some cases, microscopic observation suggested that calcination of the lime binder may have occurred in thin layers under the surface. Significant microstructural modifications were detected in the form of cracks and microcracks, due to thermal shock and gypsum dehydration. Phase transformations affected the structural integrity and the colour properties of the stucco plaster to different extents, up to a maximum depth of around 2.5. cm, while fissuring due to thermal shock penetrated to greater depths.Fire-related damage in the surface paint consisted of colour changes and/or disruption of the painted layers due to thermally-induced chemical reactions involving mineral pigments; detachment and burning of the painted layers from the direct action of flames, as well as accumulation of combustion deposits on the surface were also observed.

The paper deals with a new case of partial cranial trephination found in one of the necropolises of the Greek colony of Himera in Sicily. It is one of the very few cases of cranial trephination of Greek classical age. Macroscopic as well as radiological investigations prove that the operation was perimortal as no growth of new bone could be detected, SEM-EDS microanalysis of the piece revealed the traces left by the tool used during trephination. The review of ancient Greek and Latin medical and surgical texts permitted us to establish that the tool used in Himera was a (trypanon) mentioned by Hippocrates and named terebra by Latin authors. © 2010 John Wiley & Sons, Ltd.

Many polymers, able to confer a hydrophobicity to treated surfaces, have been proposed for the restoration and conservation of civil and monumental buildings. Polysiloxanes, and their precursors, the silanes, have been frequently employed for stone protection. To avoid decay of the treated surfaces, the effectiveness and harmlessness of the treatment need to be carefully evaluated before application in the field. In this study, a commercial alkyl-siloxane was tested as a protective treatment on a highly porous stone, starting from water solutions with different contents of the product. The treatments have been devised to try to balance the requirements and the sustainability of the conservative actions. Sustainability, in terms of costs and environmental impact, is regarded as a key factor in the 21st century. Morphological observations of the stone surface, static contact angle and colour measurements, water vapour transmission test, and tests of water absorption were carried out to characterize the untreated and treated stones. A concentration below the minimum level suggested by the manufacturer was still able to act as a good barrier against water. More concentrated solutions produced polymer accumulation and coatings with extended cracks. The properties of the treated stone were affected by the presence of cracks in the coating.

The application of photocatalytic coatings on stone has been investigated for providing surface protection and self-cleaning properties. Sol-Gel and hydrothermal processes were used to synthesise TiO2 colloidal suspensions and coatings with enhanced photocatalytic activity without any thermal curing of the coated stone. The stone was a porous limestone (apulian sedimentary carbonatic, calcite stone). Films and powders prepared from TiO2 sols were studied using X-ray diffraction to evaluate the microstructure and identify rutile and anatase phases. A morphological and physical characterisation was carried out on coated and uncoated stone to establish the changes of appearance, colour, water absorption by capillarity and water vapour permeability. The photocatalytic activity of the coated surface was evaluated under UV irradiation through NOx and organics degradation tests. The performances of the synthesised TiO2 sols were compared with commercial TiO2 suspension. Since the coating doesn't need temperature treatments for activating the photocatalytic properties, the nano-crystalline hydrothermal TiO2 sols seem good candidate for coating applications on stone that cannot be annealed after the coating application.

In this study, two commercial sacrificial anti-graffiti systems, provided as water emulsion, were applied on a highly porous stone. The behavior of the anti-graffiti treatments was investigated by means of differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy in attenuated total reflectance mode (ATR-FTIR), colorimetric tests, and water static contact angle measurements. The presence of a protective coating enhanced the removal of paint sprayed on the stone. However, penetration of the staining agent below the surface, due to the high porosity of the substrate, caused difficulties in eliminating the paint. In fact, repeated cleaning procedures, involving hot water, mechanical action, and chemical removers, did not allow a complete removal of the paint. The examined systems behaved against graffiti in different ways. No affinity between the wax-based product and the paint was observed; nevertheless, this behavior did not result in good anti-graffiti performances. On the contrary, the penetration of the paint into the fluorine-based coating yielded a good anti-graffiti effectiveness, since the stain was easily eliminated from the surfaces. The anti-graffiti coatings survived in limited areas after the cleaning processes, although the studied compounds are suggested as sacrificial products. Such behavior may affect the maintenance activities, when the surface is no longer protected and the coating need to be renewed, since compatibility problems, as well as harmful accumulation, could occur because of further treatments on these surfaces.

The presented study is aimed at developing and studying the properties of innovative products for stone protection, to apply as monomers and subject to "in situ" polymerization induced by UV/visible radiations. The tested products are based on a trifunctional methacrylic monomer, where different amounts of a vinyl terminated polydimethylsiloxane, grafted with a mercaptosilane, were added; a photoinitiator capable to operate under UV radiation, was used. The liquid formulations, firstly characterized by calorimetric analyses and rheological measurements, were applied either on glass or on stone, in order to investigate the coating properties irrespective to the substrate; a moderately porous calcarenite and a limestone with very low porosity, were used. Immediately after the treatments some specimens were exposed to an UV source to activate photopolymerization, other samples were stored in a dark area. Superficial strength, static contact angle and color properties, were measured. In addition, morphological observations by ESEM, EDS microanalyses and FTIR analyses, were carried out on the treated stone surfaces. This study highlighted a strict dependence of the coating properties not only on the exposition to the UV radiation but especially on the substrate features. Furthermore, the evaluation of the surface properties was of great importance to correct the formulation of the products and improve their performances.

A colloidal route was exploited to synthesize TiO2 anisotropic nanocrystal rods in shape (TiO2 NRs) with a surface chemistry suited for their dispersibility and processability in apolar organic solvents. TiO2 NRs were dispersed in chloroform and n-heptane, respectively, and the two resulting formulations were investigated to identify the optimal conditions to achieve high-quality TiO2 NR-based coatings by the spray-coating application. In particular, the two types of TiO2 NR dispersions were first sprayed on silicon chips as a model substrate in order to preliminarily investigate the effect of the solvent and of the spraying time on the morphology and uniformity of the resulting coatings. The results of the SEM and AFM characterizations of the obtained coatings indicated n-heptane as the most suited solvent for TiO2 NR dispersion. Therefore, an n-heptane dispersion of TiO2 NRs was sprayed on a highly porous limestone-Lecce stone-very commonly used as building material in historic constructions and monuments present in Apulia Region (Italy). A comprehensive physical-chemical investigation of the TiO2 NR based treatment on the surface of the stone specimens, including measurements of colour variation, static contact angle, water transfer properties, and morphological characterization were performed. Finally, the photocatalytic properties of the coatings were assessed under solar irradiation by using Lecce stone specimens and Methyl Red as a model target compound. The obtained results demonstrated that TiO2 NRs based coatings can be successfully applied by spray-coating resulting in an effective photocatalytic and hydrophobic treatment, which holds great promise as a material for the environmental protection of architectural stone in the field of cultural heritage conservation.