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In post-fire investigation, the damage of fire-exposed concrete is usually related to the temperature time-history. This paper presents the results of an experimental investigation on reinforced concrete, cement pastes and mortars exposed to fire, aimed at identifying the benchmarks necessary to reconstruct the thermal path 15 dry core samples were obtained from a real fire damaged structure and compared to other reference dry cores collected in not damaged zones of the same structure. In addition, 16 irregular spalling samples were collected and investigated. In order to assess changes in mineralogical composition and microstructure modifications due to temperature, 20 cubic cement pastes samples and 20 prismatic mortars specimens were realized and exposed to temperature ranging from $$200\,^{\circ }\hbox {C}$$ up to $$800\,^{\circ }\hbox {C}$$ with a gradient of $$10\,^{\circ }\hbox {C}$$ /min and keeping the maximum temperature for 1 h. Optical and Scanning Electron Microscopy, X-Ray Diffraction, Thermoanalysis and MIP porosimetry along with Helium picnometry allowed to investigate the damage degree and the mineralogical changes of the concrete and other cement based materials. Calibrated Colorimetry could determine fire temperature in the different parts of the samples due to colour changes in the mineralogical phases and in the microstructure of cement materials. The absence or presence of some specific minerals (like Portlandite), the colorimetric variations and other microstructural features are markers capable of assessing the temperature reached with high accuracy. The approach and the data showcased in this work can be useful for post-fire investigations, for theoretical and numerical models tuning and to optimize the structural retrofitting.

Obiettivo della ricerca, commissionata dalla Maffei S.p.A., è la verifica della presenza/assenza di minerali del Gruppo dell'Asbesto (o dell'Amianto), minerali considerati ad elevato rischio antropico in caso di inquinamento, nelle rocce albitiche che costituiscono il giacimento a feldspato affiorante in località . Ciarumannu (Miniera di Is Paduleddas, Orani, NU). La prospezione si è focalizzata sulla ricerca di minerali appartenenti ai cosiddetti Asbesti da Anfibolo, minerali petrogeneticamente compatibili, se non con il contesto geologico dell'area investigata, almeno con quello di aree limitrofe (Miniere di Talco della Sardegna Centrale). Sono state studiate le caratteristiche minero-chimico-petrografiche delle rocce investigate mediante l'applicazione di una serie di metodologia diagnostiche quali diffrattometria dei RX, microscopia ottica, Microscopia Elettronica a Scansione, Termoanalisi.

Air pollution, and in particular the presence of sulphur and nitrogen oxides, results in acidic rain determining the dissolution of calcite in marble and limestones. This degradation process induces evident roughness of the stone surfaces and the partial loss of carved details in artefacts. The formation of an artificial coating of calcium oxalate, obtained by treatment with ammonium oxalate, was proved to be a very promising technique for the protection of stone items. The functionalization of oxalic acid to give monoesters and monoamides (oxamates) allows tailoring the solubility of the relevant ammonium and calcium salts. In this context, theoretical calculations carried out at Density Functional Theory (DFT) level can help predicting the capability of the investigated compounds in interacting with the calcium carbonate lattice. We summarize here the experimental (X-ray diffraction, Mercury Intrusion Porosimetry, FT- MIR and FT-Raman spectroscopy, SEM) and theoretical (DFT PES and NBO analysis) investigations on the effects induced by the variation of the functionalized anions in oxalate and oxamate salts on the efficiency of the treatment of marble from the Cimitero Monumentale di Bonaria in Cagliari (Italy) and limestone samples from Cava Flore (Santa Caterina di Pittinuri, Oristano, Italy).

This study reports the results of investigations on conservation conditions of an ancient tower, called Torre del Pozzo, located in the S-W coast of Sardinia, restored about ten years ago. The tower suffers from serious problems related to vulnerability of building materials, particularly limestone and sandstones and aerial lime mortar with poor physical-mechanical properties. Over the centuries the materials were subjected to aggressive actions (wind corrasion and salt crystallization) causing an intense erosion of the walls with consequent partial collapse of the structure. About ten years ago a restoration involved the mortars and only the replacement and integration of ashlars deteriorated. After about 10 years from this intervention, some inspections have been carried out in order to assess the effectiveness of the intervention and the state of preservation of the tower. This paper focuses on analyses and tests carried out to assess condition and durability of the repair mortars. DOI: http://dx.doi.org/10.4995/FORTMED2015.2015.1761

[EN] The historical and artistic value of Coastal Towers justifies the recovery of these emblematic artifacts. For the achievement of this objective we propose a methodological approach including: i) architectural relief also by 3D laser scanner and collection of historical data; ii) macroscopic semi-quantitative evaluation of the decay, iii) application of diagnostic quantitative chemical-physical-mechanical methodologies, to assess the decay intensity, and define the criticalities for planning the restoration. The i step allows the graphic rendering of the building showing the geometry and the relationships between the parties. The ii step allows a preliminary understanding of the building materials, macroscopic alteration forms, monument features, acquisition of information about potential causes and decay mechanisms. During the iii step, sampling of building materials is planned. Laboratory analyses, to determine the soluble salts, crystalline phases, porosity as well as micro-textural features of the materials, are carried out by the application of suitable techniques.

The distribution of Coastal Towers in Sardinia testify that foreign invasions, which occurred several times over the centuries, were particularly frequent and dangerous. The beginning of the eighth century signed an increase of the attacks from the sea. The most of Coastal Towers were built in the period of Spanish rule, from 1583 to 1720. Despite numerous restorations over the years, many of these defensive structures are in critical conditions, some also affected by structural collapse. The building materials are closely related to local geological outcrops, and consist of sedimentary, magmatic and metamorphic rocks. Study of different lithotypes allowed assessing the vulnerability of different materials in different environmental conditions. Salts, transported by aerosols and deposited inside the porous structures, are the principal cause of decay of the building materials. Chemical-physical and mineralogical-petrographic analyses, performed on some Towers allowed making some general assessments on their conservation status and restoration projects.

This study reports the results of investigations on the conservation conditions of a Saracen tower, called Torre del Pozzo, located in the South-West coast of Sardinia, subjected to restoration about ten years ago. The tower suffers from serious problems related to inherent vulnerability of the materials with which it was built, in particular biomicritic limestone which constitutes the outcropping rock type in the area and lime mortar with poor physical-mechanical properties. These materials have been over the centuries subjected to particularly aggressive actions by the wind corrasion and disruptive action produced by the crystallization of salts within these porous materials. These actions have produced an intense erosion of the walls with consequent partial collapse of the structure. Essential restoration interventions have been conducted about ten years ago and involved the restoration of the mortars and the replacement and integration of ashlar stone deteriorated. After about 10 years after the intervention, some inspections have been carried out on the site in order to assess the effectiveness of the intervention and the state of preservation of the tower. Repair mortars, applied during the intervention, and biomicritic limestone, which forms the principal building material, have been characterised from a physical-mechanical and micro-structural point of view, in order to assess their condition and durability.

Coastal towers are an interesting and fascinating fragment of the historical heritage of Sardinia. Their historical and artistic value justifies the recovery of these emblematic artifacts. For the achievement of this objective we propose a methodological approach including: i) a macroscopic semi-quantitative evaluation of decay, ii) the application of diagnostic quantitative chemical-physical-mechanical methodologies, to assess the decay intensity, and define the criticalities for planning the restoration. The i) phase allows a fundamental pre-critical understanding of the building materials, the macroscopic alteration forms, the monument features, as well as the acquisition of information about potential causes and mechanisms of decay. During this phase, significant information for planning a targeted sampling of material to be analyzed, performing an appropriate selection of diagnostic techniques and/or for the monitoring, and defining the most urgent actions for recovery, must be acquired. Moreover, the architectural survey of monuments makes up the base for representing distribution of the constituent materials (rock types and mortars) and of the forms of decay. During the ii) phase, according to the information obtained by the macroscopic mapping of decay, sampling of building materials (natural stones, mortars, metals, wood) is planned. It is fundamental to georeference the sampling points and make an accurate photographic documentation. Laboratory analyses, to determine the soluble salts, crystalline phases, porosity as well as micro-textural features of the materials, are carried out by the application of suitable techniques. The chemical-physical-mechanical properties of the collected materials can be used to obtain the mappings of the decay forms, graphically represented on thematic atlas for each single monument. The final diagnosis, by the critical analysis of the visual and experimental results, is the cornerstone for planning the building recovery.

The distribution of Coastal Towers in Sardinia testify that foreign invasions, which occurred several times over the centuries, were particularly frequent and dangerous. The beginning of the eighth century signed an increase of the attacks from the sea. The most of Coastal Towers were built in the period of Spanish rule, from 1583 to 1720. Despite numerous restorations over the years, many of these defensive structures are in critical conditions, some also affected by structural collapse. The building materials are closely related to local geological outcrops, and consist of sedimentary, magmatic and metamorphic rocks. Study of different lithotypes allowed assessing the vulnerability of different materials in different environmental conditions. Salts, transported by aerosols and deposited inside the porous structures, are the principal cause of decay of the building materials. Chemical-physical and mineralogical-petrographic analyses, performed on some Towers allowed making some general assessments on their conservation status and restoration projects. DOI: http://dx.doi.org/10.4995/FORTMED2015.2015.1753