The conservation of built heritage requires detailed knowledge of the characteristics of its constituent materials and their state of conservation, making it possible to identify risk factors and conditions as well as the need for specific measures. On the basis of this knowledge the most effective intervention strategies and the most suitable conservation solutions can be selected. Over the years, IBAM, in its own diagnostic and conservation laboratories, has studied the causes and mechanisms of decay affecting a range of stone materials used in historic buildings in comparable contexts across the Mediterranean basin, together with the measures adopted for their conservation. The diagnostic activities have involved numerous case studies relating to items of historical, architectural and archaeological heritage (Teatro Petruzzelli and Cathedral in Bari; Santa Croce Basilica in Lecce; Cathedral in Altamura, etc.). Integrated methods both in situ (sonic and ultrasonic techniques, X-Ray fluorescence, penetrometric and rebound tests) and in the laboratory (optical and electronic microscopy, X-Ray diffractometry, ion chromatography, Fourier transform infrared spectroscopy and microscopy, thermogravimetry, mercury porosimetry) have been used in order to optimise the diagnostic data, searching for correlations between in situ and laboratory results, and to determine the most effective diagnostic procedures. Particular attention has been paid to the use of non-destructive in situ tests and minimally destructive laboratory analyses such as those based on Environmental Scanning Electron Microscopy technology. At the same time the durability of stone materials has been studied with a view to identifying the parameters of correlation between their intrinsic characteristics and their on-site behaviour. This has entailed the mineralogical, petrophysical, geochemical and mechanical characterisation of quarry materials, with particular reference to the search for correlations between the nature of their mineralogical constituents, their porosimetric characteristics, water absorption mechanisms, transfer of mechanical stress and artificial ageing processes based on saline crystallisation cycles. Regarding the study of conservation measures, over the years IBAM has conducted experiments to assess treatments for the conservation of stone materials used in historical, architectural and archaeological buildings. The aim is to evaluate the performance of products for conservation and restoration and to fine-tune intervention procedures with regard to both the products and the substrates to which they are applied. Particular attention has been paid to conservation issues affecting soft and highly porous stones and to verification of the application potential of innovative experimental products such as nano-structured materials (photocatalytic titania, nanosilica, etc), products with low environmental impact (such as water-based dispersions) and nanotitania-based restoration mortars. In addition, studies have been conducted to assess the results of conservation treatments under real conditions, by means of in situ monitoring of measures implemented in the past on selected Lecce Baroque artefacts. The diagnostic and conservation activities described above are strongly multidisciplinary in nature. Over the years, they have been conducted in the context of externally funded research projects, based on cooperation and partnership with other research institutes and the private sector (especially SMEs). These activities are currently being conducted in the form of services and expertise provided to conservation authorities (Superintendencies), local government, companies and restoration planners.
Le attività di conservazione del patrimonio costruito hanno un necessario presupposto nella conoscenza delle caratteristiche dei materiali costituenti e del loro stato di conservazione, attraverso cui possono essere individuati fattori e condizioni di rischio, nonché necessità di intervento, sulla base della quale impostare le più efficaci strategie di intervento ed effettuare la scelta delle più idonee soluzioni conservative. In tal senso, all'interno dei laboratori di diagnostica e conservazione, l'IBAM ha sviluppato nel corso degli anni un'attività di studio delle cause e dei meccanismi di degrado di diversi materiali lapidei dell'edilizia storica, utilizzati in contesti affini nell'ambito del bacino del Mediterraneo, e quello degli interventi per la loro conservazione. L'attività diagnostica ha affrontato numerosi casi di studio relativi a manufatti del patrimonio storico-architettonico ed archeologico (Teatro Petruzzelli e Cattedrale di Bari, Basilica di S. Croce a Lecce, Cattedrale di Altamura), all'interno dei quali metodologie integrate in situ (tecniche soniche ed ultrasoniche, fluorescenza di Raggi X, prove penetrometriche e rebound test) ed in laboratorio (tecniche di microscopia ottica ed elettronica, diffrattometria di Raggi X, cromatografia ionica, spettroscopia e microscopia infrarossa in trasformata di Fourier, termogravimetria, porosimetria a mercurio) sono state impiegate per l'ottimizzazione dei dati diagnostici, per la ricerca di correlazioni tra prove in situ ed in laboratorio, per la definizione delle più efficaci procedure diagnostiche. Particolare attenzione è stata volta all'uso di prove non distruttive in situ e alle analisi di laboratorio a bassa distruttività, quali quelle basate sulla tecnologia ESEM (Environmental Scanning Electron Microscopy). Parallelamente è stato sviluppato lo studio di durabilità dei materiali lapidei volto alla individuazione di parametri di correlazione fra caratteristiche intrinseche e comportamento in opera. Esso è stato svolto attraverso la caratterizzazione mineralogica, petrofisica, geochimica e meccanica dei materiali di cava, con particolare riferimento alla ricerca di correlazioni tra natura dei costituenti mineralogici, caratteristiche porosimetriche, meccanismi di assorbimento dell'acqua e trasferimento delle sollecitazioni meccaniche, e processi di artificial ageing attraverso cicli di cristallizzazione salina. In relazione allo studio degli interventi conservativi l'IBAM ha condotto nel corso degli anni la sperimentazione di trattamenti per la conservazione dei materiali lapidei del costruito storico-architettonico ed archeologico volta alla valutazione delle prestazioni di prodotti per la conservazione ed il restauro e alla messa a punto di procedure di intervento in relazione ai prodotti e ai substrati di applicazione. Particolare attenzione è stata indirizzata alle problematiche conservative delle pietre tenere ad elevata porosità e alla verifica delle potenzialità applicative di prodotti sperimentali innovativi, quali quelli nanostrutturati (titania fotocatalitica, nanosilice, etc.), nonché di quelli a basso impatto ambientale, quali dispersioni in soluzione acquosa, alla funzionalizzazione di malte da restauro con titania nanofasica. è stata inoltre sviluppata un'attività di studio degli esiti dei trattamenti conservativi nelle reali condizioni d'opera, attraverso il monitoraggio in situ degli interventi realizzati in passato su manufatti del Barocco leccese. Le attività di diagnostica e conservazione descritte sono contraddistinte da una forte connotazione multidisciplinare e nel corso degli anni hanno trovato spazio all'interno di progetti di ricerca con finanziamenti esterni, realizzando collaborazioni e partenariati sia con altri Istituti di ricerca che con il mondo imprenditoriale, in particolare PMI. Esse vengono inoltre correntemente svolte attraverso servizi e consulenze alle Soprintendenze, agli enti locali, alle imprese e ai progettisti del restauro.
Diagnosis, products and procedures for the conservation of built heritage
Calia Angela;Lettieri Mariateresa;Masieri Maurizio;Quarta Giovanni;Colangiuli Donato;Sileo Maria;Melica Davide;Vasanelli Emilia;
2014
Abstract
The conservation of built heritage requires detailed knowledge of the characteristics of its constituent materials and their state of conservation, making it possible to identify risk factors and conditions as well as the need for specific measures. On the basis of this knowledge the most effective intervention strategies and the most suitable conservation solutions can be selected. Over the years, IBAM, in its own diagnostic and conservation laboratories, has studied the causes and mechanisms of decay affecting a range of stone materials used in historic buildings in comparable contexts across the Mediterranean basin, together with the measures adopted for their conservation. The diagnostic activities have involved numerous case studies relating to items of historical, architectural and archaeological heritage (Teatro Petruzzelli and Cathedral in Bari; Santa Croce Basilica in Lecce; Cathedral in Altamura, etc.). Integrated methods both in situ (sonic and ultrasonic techniques, X-Ray fluorescence, penetrometric and rebound tests) and in the laboratory (optical and electronic microscopy, X-Ray diffractometry, ion chromatography, Fourier transform infrared spectroscopy and microscopy, thermogravimetry, mercury porosimetry) have been used in order to optimise the diagnostic data, searching for correlations between in situ and laboratory results, and to determine the most effective diagnostic procedures. Particular attention has been paid to the use of non-destructive in situ tests and minimally destructive laboratory analyses such as those based on Environmental Scanning Electron Microscopy technology. At the same time the durability of stone materials has been studied with a view to identifying the parameters of correlation between their intrinsic characteristics and their on-site behaviour. This has entailed the mineralogical, petrophysical, geochemical and mechanical characterisation of quarry materials, with particular reference to the search for correlations between the nature of their mineralogical constituents, their porosimetric characteristics, water absorption mechanisms, transfer of mechanical stress and artificial ageing processes based on saline crystallisation cycles. Regarding the study of conservation measures, over the years IBAM has conducted experiments to assess treatments for the conservation of stone materials used in historical, architectural and archaeological buildings. The aim is to evaluate the performance of products for conservation and restoration and to fine-tune intervention procedures with regard to both the products and the substrates to which they are applied. Particular attention has been paid to conservation issues affecting soft and highly porous stones and to verification of the application potential of innovative experimental products such as nano-structured materials (photocatalytic titania, nanosilica, etc), products with low environmental impact (such as water-based dispersions) and nanotitania-based restoration mortars. In addition, studies have been conducted to assess the results of conservation treatments under real conditions, by means of in situ monitoring of measures implemented in the past on selected Lecce Baroque artefacts. The diagnostic and conservation activities described above are strongly multidisciplinary in nature. Over the years, they have been conducted in the context of externally funded research projects, based on cooperation and partnership with other research institutes and the private sector (especially SMEs). These activities are currently being conducted in the form of services and expertise provided to conservation authorities (Superintendencies), local government, companies and restoration planners.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
