In this work Ultrasonic Pulse Velocity (UPV), Schmidt Hammer Rebound (SHR) test and strength assessment on microcores (UCSm) and standard cubic samples (UCSc) were used to detect the uniaxial compressive strength of stone masonry units. The analysis of the variability of the measurements allowed to investigate the significance of each test to differentiate the masonry blocks. The latter was evaluated by a Variability Index (VI), as the ratio between the variances at block scale and among the blocks. VI was found higher for UCSc and UPV than for UCSm and SHR measurements. A regression analysis aimed to the correlation of uniaxial compressive strengths evaluated by conventional destructive test on stone cubes with the other test results. The findings showed a good linear correlation among UCSc and UPV values (R-2 = 0.83), thus supporting the reliability of UPV to screen the masonry units and to estimate their uniaxial compressive strength. The correlation of UCSc with UCSm was reasonable (R-2 = 0.76), while it was low with SHR results; some limits related to the use of SHR and UCSm tests are also discussed.

Rod-shaped TiO2 nanocrystals (TiO2 NRs), capped by oleic acid molecules (OLEA), were synthesized with controlled size, shape and surface chemistry by using colloidal routes. They were investigated for application as coating materials for preserving architectural stone of monumental and archaeological interest, in consideration of their self-cleaning and protection properties. For this purpose, two different deposition techniques, namely casting and dipping, were tested for the application of a nanocrystal dispersion on a defined stone type, as a relevant example of porous calcarenites, namely the Pietra Leccese, a building stone widely used in monuments and buildings of cultural and historic interest of the Apulia region (Italy). The physical properties of the stone surface were investigated before and after the treatment with the prepared nanostructured materials. In particular, colour, wettability, water transfer properties and stability of the coating were monitored as a function of time and of the application method. The self-cleaning properties of the TiO2 NRs coated surfaces were tested under simulated and real solar irradiation. The obtained results were discussed in the light of the specific surface chemistry and morphology of TiO2 NRs, demonstrating the effectiveness of TiO2 NRs as an active component in formulations for stone protection.

In this study, some NDTs (Ultrasonic Pulse Velocity UPV and Rebound Hammer) and uniaxial compressive test on microcores (UCSm) as a moderately destructive test, were investigated as tools for assessing the uniaxial compressive strength (UCS) of a soft limestone. Correlations between UCS and results of each above-mentioned tests were determined by a univariable regression analysis. Artificial Neural Network and the Multiple Regression Analyses were considered to search correlations between UCS and combined results of the non-invasive tests. An iterative cross-validation procedure was implemented to validate the predictive performances of the models. It was found that combining UPV and UCSm results gives the best reliability in the indirect estimation of UCS, with a notably reduced predictive error.

In this paper we deal with an experimental activity aimed to the characterization ofa compact local limestone, named Trani stone. Compact limestones are very commonmaterials used in the monumental and historic built heritage. In particular, withreference to the Apulian region (Southern Italy), they are the constituent stones of thenumerous Romanesque Cathedrals, as well as of many other important monuments suchas the UNESCO site of Castel del Monte. They have also been employed for thebuilding of the fortified towns and norman-swabian castles facing the sea. The studyreports mineralogical-petrographical and physical features, with particular reference tothe behaviour with respect to the water. Ultrasonic tests have also been performed asindirect tool for the qualification of the stone in dry and wet conditions. A superficialtreatment with photocatalytic titania (in water and alcoholic solution) has also beenapplied to the stone, in order to study the potential use of self-cleaning and antipollutionnanotitania coatings for stone surface protection; a preliminary assessment ofthe morphology and distribution of the titania films on the stone surface and relatedcolour changes has been carried out.

The Mediterranean basin typically shows the ubiquitous presence of historical towns constitutinga rich architectural heritage that has only recently become the object of conservation policy.Diagnostic knowledge can effectively contribute to the adoption of suitable conservation strategies. Thiswork focuses on the historical building materials employed in the Sicilian town of Syracuse (SouthernItaly), with the aim of identifying the causes and mechanisms of deterioration of the materials employed,as well as possible remedies. An extensive survey of the stones and their main decay morphologieswithin buildings was carried out. Laboratory analyses by optical microscopy, mercury intrusion porosimetryand ion chromatography were also performed. Several soft and porous calcarenites, having differentmineralogical-petrographical and porosity features, were recognized. The study identified a decayscenario typical of a Mediterranean context, with sea spray as the main cause of decay, together withwater and wind. Different decay levels observed in the stones were related to their fabric and porosimetricstructure, but specific use and position within buildings also proved important. The findings of thisstudy are of interest for similar urban and geographical contexts where soft and porous calcarenites areemployed, and provide information for conservation works.

Clay minerals often occur in the finishing layers covering the surface of historic and architectural artefacts. They may come from ochres intentionally applied or from atmospheric dust naturally deposited. In the first case the finishes could testify to treatments applied for the stone conservation and/or aesthetic purposes, whose study is of great interest in conservation activities.In this paper we report on the application of microdestructive analytical techniques in order to identify the presence and the origin of clay minerals found on the surfaces of several historic buildings located in the Apulia region (Southern Italy). Optical and SEM observations, along with EDS microanalyses, and FTIR analyses were performed. The microdestructive character of these techniques made it possible to carry out theanalyses on the same specimen, thus reducing the sampling. XRD analyses were also performed to confirm the presence of clay minerals. The complementary analytical findings were helpful in most cases in establishing the real origin of the clay minerals; the detection of organic materials arising from man-made treatments allowed to identify clays as pigments. However, in some cases the uncertainty remained between ochre,intentionally employed, and soil-dust deposition.

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.

This paper proposes a new approach, based on the cross validation analysis of data, to establish reliable models for estimating the in situ compressive strength of concrete from the results of indirect tests, including Ultrasonic Pulse Velocity test and compressive test on microcores. The method was validated on a database obtained from an extensive diagnostic campaign performed on an existing building. The reliability of the proposed method was evaluated along with the results obtained by means of the Alternative 1 approach of EN 13791 standard by comparing the mean and the characteristic values of the estimated uniaxial compressive strengths issued from the two methods with the real ones obtained directly from the cores. Compared to the standard approach, the proposed method resulted in a better reliability in estimating the in situ compressive strength, even with a lower number of cores used to obtain the relationships.

Over the last few years, photocatalytic titanium dioxide coatings have been explored in laboratory conditions tocreate building materials with self-cleaning and depolluting abilities. Assessing the performances of the photocatalyticsurfaces under real conditions may provide basic knowledge to evaluate the potential of real applicationsof TiO2 coatings in buildings.In this study, the performance of photocatalytic limestone surfaces obtained through coating with waterdispersedTiO2 nanoparticles were investigated in an urban environment. Coated and uncoated samples wereexposed to an urban site for one year. Before the exposure and periodically afterwards, optical microscopyobservations, colour and contact angle measurements were performed on the sample surface. At the end of theexposure period, samples underwent a capillary water absorption test and self-cleaning efficiency was evaluatedby a Rhodamine B photodegradation test. Ti and soluble fraction amounts on the sample surfaces were determinedby X-ray Fluorescence (XRF) and ion chromatography, respectively. The overall results showed theTiO2 coating was better able to preserve the surface colour properties early after exposure. After eight months,this effect was lost and the self-cleaning efficiency was reduced to negligible final rates. No clear wettabilityresults and no meaningful capillary behaviour were recorded. A decrease of the photocatalytic activity was dueto both partial titania loss and deactivation phenomena. The role of soluble salt ions either adsorbed from theenvironment or produced by the photocatalytic abatement of pollutants was recognized in the deactivation ofthe photocatalysts and their accumulation deserves attention for possible stone damage risk implications.

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.

Restoration mortars for use in hystorical buildings should fullfill compatibility critera withrespect to the preexisting materials, in order to ensure harmlessness and effectiveness of therestoration solutions. Nevertheless, a satisfactory evaluation of the suitability of the mortarsfor restoration is quite difficult due to the lack of proper standards of reference for the specificneeds in the field of the Cultural Heritage, as well as for the lack of threshold parameters forthe evaluation of the compatibility with the preexisting materials. This paper describes thestudy for the set-up of an hydraulic mortar for restoration, specifically for masonry rendering.The mortar was designed for applications on soft and porous calcareous stones. The mix wasbased on natural hydraulic lime (NHL) added with metakaolin. Grinded dolomitic limestoneswere used as aggregate, and several admixtures with different functions were added. Theexperimental activity concerning the characterisation of the mortar was carried out on freshand hardened samples. The standard specifications for the renovation mortars, that meet somesuitable requirements for restoration, were assumed as reference parameters for the mortardesign and its qualification in terms of density, water vapour permeability, water absorptionby capillary action, flexural and compressive strengths. Attention was paid to the porosimetriccharacteristics, that were determined by Mercury Intrusion Porosimetry. The durability wasalso assessed by salt ageing test. The behavior of the mortar with respect to some soft andporous calcarenites was also concerned by the adhesive test on composite mortar/stonespecimens. Tests of evaporation of Na2SO4 saline solution were also performed on themortar/stone system, in order to assess the harmlessness of the mortar layers with respect tothe transport of the saline solution and to the effects of the salt crystallization at the interface.Finally, an overall evaluation of the performance of the mortar was traced on the basis of theresults of the analyses and tests.

The integration of high-resolution, non-invasive geophysical techniques (such as ground-penetrating radar or GPR) with emerging sensing techniques (acoustics, thermography) can complement limited destructive tests to provide a suitable methodology for a multi-scale assessment of the state of preservation, material and construction components of monuments. This paper presents the results of the application of GPR, infrared thermography (IRT) and ultrasonic tests to the 13th century rose window of Troia Cathedral (Apulia, Italy), affected by widespread decay and instability problems caused by the 1731 earthquake and reactivated by recent seismic activity. This integrated approach provided a wide amount of complementary information at different scales, ranging from the sub-centimetre size of the metallic joints between the various architectural elements, narrow fractures and thin mortar fillings, up to the sub-metre scale of the internal masonry structure of the circular ashlar curb linking the rose window to the fac¸ade, which was essential to understand the original building technique and to design an effective restoration strategy.

This study concerns the experimental activity for the set-up of new hydraulic mortars for restoration. Different mix wererealized with specific attention to the needs required in the restoration field. Two new formulations were selected and theirphysical-mechanical properties were determined following the standards tests for mortar's characterization. The durability ofthe new products was evaluated by salt ageing tests as well as their performance with respect to the migration of the salinesolution within the stone/mortar system in terms of harmfullness.

Lungo la fascia costiera della Puglia meridionale, sui versanti ionico e adriatico, affiorano svariate litologie calcarenitiche, appartenenti alla Formazione della Calcarenite di Gravina e a quella dei Depositi Marini Terrazzati. Esse hanno da sempre costituito fonte di approvvigionamento di rocce tenere largamente utilizzate nel patrimonio costruito dall'antichità fino a tempi molto recenti. Il sistema dei depositi calcarenitici costieri e delle cave in esso presenti rappresenta senza dubbio un insieme di geoarcheositi, all'interno dei quali, evidenze di importanza archeologica e storica si associano ad elementi di significato geologico e geomorfologico.I siti di Torre Ovo, Campomarino, Marina Serra, Porto Miggiano, Torre Santa Sabina, Torre Canne, Egnazia, San Vito di Polignano e Capitolo, considerati nel presente lavoro, rappresentano esempi significativi da salvaguardare e valorizzare per la molteplicità, la peculiarità e l'interesse degli elementi geomorfologici, geostratigrafici e archeologici che essi offrono per la comprensione dell' evoluzione del territorio negli ultimi due millenni.

The study examines a unique artistic production that developed in Salento in the second half of the nineteenth century: the majolica artifacts. The development of the maiolica product, much used as a piece of furniture, was promoted by the opening of a factory by one of the most visionary and pioneer protagonists of Lecce, Angelantonio Paladini. At San Pietro in Lama village near Lecce, he made a "steam plant" for the production of majolica artifacts. He introduced throughout the Lecce province (there are many majolica pavements and decorative tiles made within palaces, churches and villas) the elaborate works seen in Campania, mostly made up of quatrefoil motifs, composed by the union of four "formelle". The failure of its industry also marked the decline of this type of production, which left in Salento significant examples of high artistic value, that are little known and insufficiently studied.In this short excursus we present some majolica pavements located in several buildings, both religious and civil, of Salento. We refer in particular to the floors of the churches of Santa Maria della Provvidenza (Alcantarine) and Madonna degli Studenti in Lecce, the churches of San Luigi in San Pietro in Lama and San Giovanni Battista in Carmiano, as well as those that decorate the small coffee house within the garden of the Personè castle in Nardò and the floors of the Plantera (now "Maglietta") palace in Novoli. The study also shows the state of conservation of these artifacts, with the most common forms of alteration that affect them. Laboratory analyses were performed on some samples coming from the tiles of some artifacts. They allowed to identify the materials used for the manufacture of the ceramic body and the finishing on the surface, as well as their technics of execution.

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.

In this paper, the use of ultrasonic pulse velocity (UPV) testing as a reliable technique to determine the compressive strength of a calcarenitic stone typical of Salento (South of Italy), known as Lecce Stone (LS) has been investigated. The scope of the experimental research is to establish correlations between the results obtained by non-destructive and destructive tests, in order to reduce the use of destructive methods within the diagnostic procedures for the mechanical analysis and qualification of ancient masonries. Furthermore, the presence of water as a variable affecting the test was investigated. The results of the tests show that the UPV values are well correlated with the compressive strengths and this method showed to be efficient in predicting the strength of LS.

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.

Many building materials have been functionalizedto achieve photocatalytic properties, namely selfcleaningand depolluting abilities, through the applicationof photocatalytic TiO2 nanoparticles to those materials.These nanoparticles are able to preserve building fac¸adesby blocking the deposition of airborne particulates in pollutedurban environments, and they are able to purify theair, thus benefiting the environment. In this study, theapplication of nanostructured TiO2 as a photoactive coatingon two types of natural stone was investigated. A TiO2 solobtained by sol-gel synthesis followed by hydrothermalprocessing was applied via spray deposition onto a compactlimestone and a highly porous calcarenite. The effectsof this coating on some basic properties of the stone, suchas its color and water absorption, and the photocatalyticeffectiveness of the coated surface were then studied.Scanning electron microscopy and energy-dispersive X-rayspectroscopy showed that the coating presented a uniformmorphology on both types of stone, with the TiO2nanoparticles penetrating\1 lm into the stone. The coatingwas found to be compatible with the properties of theinvestigated types of stone. Colorimetry indicated that thechange in the color of the stone due to the coating wasnegligible. Measurements of the static contact angle andthe results of the capillary water absorption test showedthat photoinduced superhydrophilicity did not increase theamount of the water absorbed by the coated stone. Aphotodegradation test of rhodamine B demonstrated theself-cleaning ability of the coating on both types of stone.Conversely, the photocatalytic effectiveness of the coating--as measured by a nitrogen oxide abatement test--wasfound to be higher for the porous calcarenite than for thecompact limestone, and to depend on the porosity androughness of the substrate.

The crypt of St. Nicholas in Bari, Southern Italy, is a building of cultural worldwide importance. Inside the crypt a mosaic develops on the apsidal floor and along a parietal seat placed along the apsidal masonry, in the form of cladding. A surviving portion of the mosaic pavement is also preserved in the right lateral chapel. Integrated non-destructive survey and laboratory analyses were undertaken for the diagnostic study of the mosaic. GPR prospection was successfully applied to the study of its conservation state, that is strictly related to the condition of the subsoil, in particular to the presence and distribution of water. The presence of water, whose rise interests also some portions of the masonry and water content distribution were identified by the results of electromagnetic wave velocity analysis in GPR data. The decay visible on the tesserae evidenced widespread spalling and crumbling as typical forms that selectively affect the different materials of the tesserae of the mosaic. Samples taken from them were investigated by optical microscopy, X-ray diffraction, ion chromatography, infrared spectroscopy and thermogravimetric analyses, in order to identify the constituent materials and the products of their decay. The application of the integrated methodologies showed its effectiveness in order to acquire a quite complete knowledge for diagnostic purpose. Decay appeared to be due to the combined presence of water and soluble salts and it has different effects depending on the materials characteristics.

One of the major goals in the field of rehabilitation and renovation of existing structures is to determine mechanical properties of materials as well as their level of damage, namely the presence of defects, cracks, weathering effects, etc., by means of non-destructive (NDT) techniques. NDT tests, in fact, are easier and more economics than destructive ones because they do not necessitate sample extraction and preparation; furthermore they are often the unique way to assess the material properties in case of historic and architectural buildings, where the possibility of extracting core samples is limited or not possible. The ultrasonic pulse velocity testing has been proved to be a useful and reliable non-destructive test for assessing the compressive strength and the elastic modulus of concrete in existing structures. Furthermore, the use of both ultrasonic tests and Schmidt hammer tests allow to have a good estimation of concrete compressive strength (SONREB method) by reducing the influence of the variables affecting the two technique when used alone. Both the technics have also been suggested to investigate mechanical and physical properties of rocks, but further experimental data are needed to confirm the reliability of the method. The present work is a part of a wider research aimed at set up non-invasive diagnostic procedures for the mechanical analysis and qualification of the ancient masonries; it is specifically devoted to verify the effectiveness and/or to point out critical aspects and limits of the above mentioned non-destructive tests - already applied in the field of concrete and compact stones -with reference to the characterization of soft stones.

Mixtures based on aqueous solutions of nanostructured TiO2 and of a fluoropolymer were developed. They were applied on a limestone substrate. The obtained coatings were proved able to provide the functionalization of the stone with simultaneous photocatalytic and hydrophobic properties. They showed a high photodegradation activity (?90%), although with different kinetics, depending on the amounts of nanoparticles within the polymer. Hydrophobic effectiveness was also dependent on the TiO2 loads; good hydrophobicity was obtained when they were tuned to proper amounts. The addition of TiO2 to the polymer was found to decrease the color impact of the coatings on the stone surface.

The enhanced photocatalytic activity for degradation of a wide range of pollutants makes nanostructured TiO2 an ideal candidate for self-cleaning coatings.The deposition of different types of TiO2 nanocrystalline coatings on stone has been investigated in order to test the surface protection and self-cleaning abilities of the nanostructured materials. TiO2 nanocrystals with controlled size, shape and surface chemistry have been prepared by using two distinct synthetic approaches, namely colloidal synthesis by hot injection and hydrothermal nanophase crystallisation. Two different types of stones, possessing different porosity, namely porous calcarenite and a compact limestone have been selected, being both widely used in South Italian monuments and building relevant for cultural heritage.The physical properties of coated and uncoated stone surfaces, respectively, have been investigated, and colour, wettability and stability of the coatings have been checked. The self-cleaning properties of the nanostructured TiO2 coated surfaces under solar irradiation have been tested by monitoring the degradation of a model organic molecule, namely an organic dye. The obtained results have confirmed that the nanocrystalline TiO2 coatings are promising candidate for environmental protection upon appliance on either porous and compact stone. Moreover, the nanostructured TiO2 obtained colloidal synthesis by hot injection has demonstrated to provide hydrophobic treated surfaces.

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.

A deep knowledge of the physical and mechanical properties of the constituent materials of ancient masonries is of crucial importance in the choice of the proper intervention techniques. In case of historical buildings sustainable diagnostic procedures responding to the conservation constraints, should have the lowest degree of intrusion and the fullest respect for their physical integrity. The extraction of samples from existing structures for laboratory tests is one of the major problems in the field of the diagnosis of ancient buildings and this has moved the scientific community to propose alternative non-destructive techniques to evaluate the mechanical and physical properties of building stones. In the present work, non-destructive (NDT) and destructive (DT) tests have been investigated as tools for assessing the compressive strength of "Lecce stone", a soft calcarenite used as traditional building material in the Southern Italy. Ultrasonic pulse velocity and Schmidt hammer test have been compared with standardized mechanical destructive tests on cubes in order to research correlations between the results. The final aim is to assess the reliability of the non-destructive investigated methods in describing the mechanical performance of the stone, limiting the use of destructive analyses on masonries. Compressive strength on microcores, reducing at least the intrusion of the sampling for mechanical test in laboratory conditions, was also determined and good correlation was found with the strength results obtained by the standard compressive test.

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.

This paper deals with the use of building materials within the built heritage of the Southern Italy, their decay problems and the research of stone parameters material to their durability. The study documents the most common and widespread stone building materials and their forms of decay within the historical-architectural heritage, as well as in the archaeological artifacts. The heavy presence of the decay forms related to granular disgregation and loss of powder material from the surface suggest an high susceptibility of such materials to the disruptive processes induced by water penetration and salt crystallisation. The study of the stone properties and artificial ageing tests in laboratory, carried out by comparing several lithologies, are aimed to understand their response to the decay with relation to the petrophisical and compositional features, with the final purpose to identify durability parameters, usefull for choosing the appropriate conservation measures. In order to this final purpose, further elements of evaluation are drawn by the activity in progress, concerning the monitoring of the conservation treatments carried out on the Baroque heritage of Lecce town (Southern Italy) during the last decades.

The crypt of St. Nicholas in Bari, Southern Italy, is a building of cultural worldwide importance. Inside the crypt a mosaic develops on the apsidal floor and along a parietal seat placed along the apsidal masonry, in the form of cladding. A surviving portion of the mosaic pavement is also preserved in the right lateral chapel. Integrated non-destructive survey and laboratory analyses were undertaken for the diagnostic study of the mosaic. GPR prospection was successfully applied to the study of its conservation state, that is strictly related to the condition of the subsoil, in particular to the presence and distribution of water. The presence of water, whose rise interests also some portions of the masonry and water content distribution were identified by the results of electromagnetic wave velocity analysis in GPR data.The decay visible on the tesserae evidenced widespread spalling and crumbling as typical forms that selectively affect the different materials of the tesserae of the mosaic. Samples taken from them were investigated by optical microscopy, X-ray diffraction, ion chromatography, infrared spectroscopy and thermogravimetric analyses, in order to identify the constituent materials and the products of their decay.The application of the integrated methodologies showed its effectiveness in order to acquire a quite complete knowledge for diagnostic purpose. Decay appeared to be due to the combined presence of water and soluble salts and it has different effects depending on the materials characteristics.

The ultrasonicpulse velocity (UPV) method can be conveniently used to check the quality of stones and alsofor material characterization. Both the intrinsic characteristic of the stone (porosity, grain size,anisotropy, etc.) and the external factors (humidity, stress, temperature, presence of cracks)may affect the elastic wave propagation, thus in order to correctly estimate the ultrasonicbehavior of the investigated material it is important to know in what manner and how muchthe variation of the experimental conditions may modify the characteristics of the wavesbeing measured. This aspect is of crucial importance when in situ measurements are made.In this work the attention isfocused on two parameters: the wave frequency used in the measurements and the applicationof an external load. In the presentwork the effect of loading on the UPV has been investigated for the Lecce stone varying thewave frequency and the specimen geometry.Results provide further knowledge about the response of soft stones to UPVpropagation, evidencing that, as for concrete and mortars, UPV are not influenced so much bythe application of load before that crack damage occurs. This result supports the possibility ofusing ultrasonic pulse velocities to characterize physical and mechanical properties of thestone within a building.Moreover, the obtained results suggest that when UPV are employed to assess the quality ofstones or their mechanical and physical properties, it would be a good practice to use morethan one frequency of measurement.

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.

The ultrasonic pulse velocity ( UPV) method can be conveniently used for non-destructive testing of physical-mechanical properties of the stones within historical masonry, as well as to check the state of damage and microcracking. Before to proceed with in situ measurements, it is important to assess the contribution that both intrinsic characteristics of the stones and external factors may give to the ultrasonic response. In this work the effect of different wave frequencies, sample geometry and application of a compression load on the response of a natural stone to UPV test has been investigated. An extensive experimental campaign in laboratory conditions was carried out on a soft limestone, used in the historical building heritage of the Southern Italy. A negligible UPV dispersion was found at the used frequencies of 1 MHz, 120 and 55 kHz when a compression load was not applied; the measured velocities were found to be influenced by the stone inhomogeneity rather than by the sample size. They showed a slight decrease and still negligible dispersion under load up to the visible damage. Dispersion increased with the cracking progression. This indicates that enhanced capability of UPV, in checking material quality and damage conditions, can be obtained by combining the use of different wave frequencies.

UPV as non-destructive technique can effectively contribute to the low invasive in situ analysis and diagnosis of masonry elements related to the conservation, rehabilitation and strengthening of the built heritage. The use of non-destructive and non- invasive techniques brings all the times many advantages in diagnostic activities on pre-existing buildings in terms of sustainability; moreover, it is a strong necessity with respect to the conservation constraints when dealing with the historical-architectural heritage.In this work laboratory experiments were carried out to investigate the effectiveness of ultrasonic pulse velocity (UPV) in evaluating physical and mechanical properties of Lecce stone, a soft and porous building limestone. UPV and selected physical-mechanical parameters such as density and uniaxial compressive strength (UCS) were determined. Factors such as anisotropy and water presence that induce variations on the ultrasonic velocity were also assessed. Correlations between the analysed parameters are presented and discussed.The presence of water greatly affected the values of the analysed parameters, leading to a decrease of UPV and to a strong reduction of the compressive strength. A discussion of the role of the water on these results is provided.Regression analysis showed a reliable linear correlation between UPV and compressive strength, which allows a reasonable estimation of the strength of Lecce stone by means of non-destructive testing methods such as the ultrasonic wave velocity. Low correlation between UPV and density was found, suggesting that other factors than density, related to the fabric and composition, also influence the response of the selected stone to the UPV. They have no influence on the UCS, that instead showed to be highly correlated with the packing density.