195 pubblicazioni classificate nel seguente modo:

A Modern Multidisciplinary Method to Characterize Natural White Spot Lesions with 2D and 3D Assessments: A Preliminary Study
JOURNAL OF PERSONALIZED MEDICINE
Autore/i: Vitiello, Flavia; Orilisi, Giulia; Notarstefano, Valentina; Furlani, Michele; Riberti, Nicole; Bellezze, Tiziano; Carrouel, Florence; Putignano, Angelo; Orsini, Giovanna
Classificazione: 1 Contributo su Rivista
Abstract: In this preliminary study, a multidisciplinary method based on high-resolution analytical techniques (such as microcomputed tomography, Raman Microspectroscopy, scanning electron microscopy, and Vickers microhardness test) was exploited to evaluate the alterations that occur in human teeth at the initial stage of the carious lesion. To this purpose, six extracted molars displaying a natural white spot lesion (WSL) were investigated. Specific morphological, structural, and chemical parameters, such as the mineral density, indentation hardness, molecular and elemental composition, and surface micromorphology were obtained on the WSL, and the results were statistically compared (t-test, p < 0.05) to those of the sound enamel on the same tooth. In the WSL, with respect to the sound area, a decrease in the mineral density and crystallinity was detected together with differences in the molecular composition and surface microstructure, such as the occurrence of micropores and irregularities. Moreover, the elemental analysis highlighted in WSL showed a statistically significant decrease in Ca and P percentages. In conclusion, this multidisciplinary approach allows us to fully characterize the area of interest, providing a deeper knowledge of these enamel lesions, which could have important clinical implications.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/331212

Effect of build-up orientation angle and printing speed on mechanical properties and micro- and macro-defect formation in 17-4 PH stainless steel components manufactured by Bound Metal Deposition
INTERNATIONAL JOURNAL, ADVANCED MANUFACTURING TECHNOLOGY
Autore/i: Mancia, Tommaso; Forcellese, Pietro; Bellezze, Tiziano; Simoncini, Michela
Classificazione: 1 Contributo su Rivista
Abstract: In the present work, the effect of build-up orientation angle and printing speed on mechanical properties of 17-4 PH stainless steel components realized by Bound Metal Deposition technology was investigated. Furthermore, the presence of microscopical and macroscopical defects was analyzed as a function of the printing parameters investigated. To this purpose, tensile specimens, printed with different build-up orientation angles (0 degrees, 45 degrees, and 90 degrees) and printing speeds (15, 30, 45, and 60 mm/s), were tested at room temperature to evaluate the mechanical properties as a function of the process parameters. Furthermore, stereo optical microscopy and scanning electron microscopy coupled to energy dispersive X-ray spectroscopy were used, respectively, to observe the macroscopical and microscopical defect presence on the 3D printed parts built with different build-up orientation angles and printing speeds. It was demonstrated that the build-up orientation angle and printing speed significantly affect the mechanical properties and the surface finish of 3D printed components, as well as the presence of micro-defects due to the layer-by-layer filament deposition. In particular, the build-up orientation angle of 45 degrees confers less mechanical to the specimens than the other two orientations investigated, both in terms of ultimate tensile strength, yield strength, and modulus of elasticity. Furthermore, high print speeds do not significantly contribute to a worsening of mechanical performance but influence the surface finish which is characterized by greater printing defects.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/329292

Effects of temperature, strain and strain rate on shape memory thermoplastic polyurethane processed by injection molding
JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
Autore/i: Coccia, M.; Farotti, E.; Chiappini, G.; Bellezze, T.; Sasso, M.
Classificazione: 1 Contributo su Rivista
Abstract: Shape memory polymers (SMPs) represent a materials class capable of recovering their initial shape, when submitted to deformations, through an external stimulus. This paper focuses on a Shape Memory Thermoplastic Polyurethane (SMPU), characterized by a one-way shape memory effect (SME) activated by temperature. The material was characterized by Differential Scanning Calorimetry (DSC) to find transition temperature; then, it was manufactured by an injection molding machine to perform a campaign of characterization tests. Thermomechanical tests were conducted varying the prescribed strain (up to 25%, 50%, and 80%), imposed at both different strain rates ((Formula presented.), (Formula presented.), and (Formula presented.) s−1), and temperatures (50°C, 60°C, and 70°C); the results were investigated in terms of shape fixity and shape recovery ratios. An excellent memory capability was observed for all the tested conditions; otherwise, the shape recoverability is strongly influenced by all investigated parameters, especially by the strain rate, resulted to be the most effective one. In fact, the shape recovery ratio can increase as much as 20%, when the strain rate is increased from (Formula presented.) to (Formula presented.) s−1. An opposite effect was observed with the variation of prescribed strain and temperature, the increase of which reduces the ability of the material to return to its original shape.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/312794

Biochar and recycled carbon fibres as additions for low-resistive cement-based composites exposed to accelerated degradation
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Mobili, A.; Cosoli, G.; Giulietti, N.; Chiariotti, P.; Bellezze, T.; Pandarese, G.; Revel, G. M.; Tittarelli, F.
Classificazione: 1 Contributo su Rivista
Abstract: Biochar (BCH) and recycled carbon fibres (RCF) were used as carbonaceous additions in low-resistive mortars/concretes. Their effects on mechanical, electrical, and durability properties were investigated. Tests were performed both during curing and accelerated degradation. The combined use of RCF and BCH decreased the electrical impedance of cement-based matrices, enabling the use of low-cost monitoring instrumentation, and improved their mechanical performance. Recycled carbon fibres and biochar additions increased carbonation and capillary water absorption but acting as a barrier they made water and chlorides penetrate less deeply.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/312647

Multidisciplinary evaluation of the remineralization potential of three fluoride-based toothpastes on natural white spot lesions
CLINICAL ORAL INVESTIGATIONS
Autore/i: Orilisi, Giulia; Vitiello, Flavia; Notarstefano, Valentina; Furlani, Michele; Riberti, Nicole; Monterubbianesi, Riccardo; Bellezze, Tiziano; Campus, Guglielmo; Carrouel, Florence; Orsini, Giovanna; Putignano, Angelo
Classificazione: 1 Contributo su Rivista
Abstract: Objectives: This in vitro study aimed assessing the remineralization potential of three commercial fluoride-based toothpastes in permanent teeth with natural white spot lesions (WSLs). A multidisciplinary approach based on Raman microspectroscopy (RMS), Scanning electron microscopy (SEM), Energy-dispersive x-ray spectroscopy (EDS), and Vickers microhardness (VMH) was exploited. Methods: N = 12 human molars with natural WSLs in the proximal-vestibular zone were selected and divided into 4 groups (n = 3) according to the different treatments: HAF (hydroxyapatite with fluoride ions); SMF (sodium monofluorophosphate with arginine); SF (sodium fluoride with enzymes), and CTRL (untreated group). All toothpastes tested contained 1450 ppm of fluoride. Teeth samples were submitted to the following protocol: a 7-day pH cycling treatment, with two daily exposures (2 min each time) to the commercial toothpastes described above. The surface micromorphology (SEM), the chemical/elemental composition (RMS and EDS), and the Vickers microhardness (VMH) were evaluated. Statistical analysis was performed. Results: A remarkable remineralization of WSLs in SEM images was observed in all treated groups compared to CTRL. In particular, HAF and SF displayed higher values of VMH, phosphates amount (I960), crystallinity (FWHM960), and lower ones of C/P (I1070/I960) with respect to CTRL. Intermediate values were found in SMF, higher than CTRL but lower with respect to HAF and SF. As regards the Ca/P ratio, statistically significant differences (p < 0.05) were found between SF and the other groups. Conclusions: All the tested dentifrices have shown to remineralize the WSLs. SF and HAF have comparable capability in hardness recovery and crystallinity; however, SF shows the best remineralizing potential according to both micromorphological and chemical analyses. Clinical relevance The daily use of toothpastes containing hydroxyapatite partially replaced with fluoride, sodium monofluorophosphate with arginine and sodium fluoride toothpaste associated with enzymes represents a preventive, therapeutic, effective, and non-invasive tool for remineralize WSLs.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/323891

Effect of printing orientation on mechanical properties of components in stainless steel obtained using the Bound Metal Deposition technology
16th CIRP Conference on Intelligent Computation in Manufacturing Engineering, CIRP ICME 2022
Autore/i: Bellezze, T.; Forcellese, A.; Forcellese, P.; Mancia, T.; Simoncini, M.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The present work aims at studying and analyzing the influence of process parameters on performances of 3D printed components obtained using the Bound Metal Deposition technology. Bound Metal Deposition is one of the latest technologies for metals 3D printing. It consists in an extrusion process in which the parts are fabricated layer-by-layer through the deposition of metal powder held together by wax and polymer binder. After printing, binder is removed using a solvent, and the additively manufactured parts are sintered for their consolidation at temperatures reaching 1400°C for about 40 hours. Tensile specimens in 17-4 PH stainless steel were additively manufactured imposing different printing orientations in order to evaluate the effect of growth orientation angle on the mechanical properties of 3D printed parts. Results have demonstrated that the printing orientation greatly affects the mechanical performances of 3D printed components.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/323494

Thermal Properties of Alternative Phase Change Materials for Solar Thermal Applications
INTERNATIONAL JOURNAL OF HEAT AND TECHNOLOGY
Autore/i: Tomassetti, Sebastiano; Luzi, Francesca; Cheng, Pengyu; Forcellese, Pietro; Aquilanti, Alessia; Bellezze, Tiziano; Di Nicola, Giovanni
Classificazione: 1 Contributo su Rivista
Abstract: Phase change materials (PCMs) with a solid-solid phase transition are receiving increasing attention as promising materials for thermal energy storage (TES) systems. Unlike the more well-known and widespread solid-liquid PCMs, they generally have negligible volume change during phase transition, no contamination, and long cyclic life. Among the most studied solid-solid PCMs, a group of organic materials known as plastic crystals and their mixtures seem to show energy storage properties suitable for solar thermal systems at low-medium temperatures (80-150 & DEG;C). In this study, to deeply analyze their suitability for these applications, the thermophysical properties and thermal stability of two promising plastic crystals, pentaerythritol (PE) and pentaglycerine (PG), and their mixture are reviewed. The phase transition properties of these two pure substances were also assessed in this study through differential scanning calorimetry (DSC). The experimental measurements showed good agreement with the data collected from literature. The analysis showed that various properties and characteristics of these materials should be further investigated since a limited number of studies related to their properties is available. However, if their drawbacks are adequately addressed, the studied plastic crystals seem suitable for TES applications.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/327470

Commercial and recycled carbon-based fillers and fibers for self-sensing cement-based composites: Comparison of mechanical strength, durability, and piezoresistive behavior
JOURNAL OF BUILDING ENGINEERING
Autore/i: Belli, Alberto; Mobili, Alessandra; Bellezze, Tiziano; Cachim, Paulo B.; Tittarelli, Francesca
Classificazione: 1 Contributo su Rivista
Abstract: The possible use of industrial by-products as carbon-based fillers and/or fibers to produce Multifunctional Cement-based Composites (MCC) with piezoresistive behavior for Structural Health Monitoring (SHM) was investigated. As fillers, Used Foundry Sand (UFS) and Gasification Char (GCH) were compared with commercial Graphene Nanoplatelets (GNP). As fibers, 6 mm long recycled carbon fibers (RCF) were compared with virgin ones. Mortars were tested in terms of mechanical strength, water absorption, microstructure, and piezoresistive behavior. UFS and GCH are more effective than GNP in decreasing the mortar electrical resistivity (− 30%), total porosity (− 11%), water absorption (− 27%) and in increasing the compressive strength (+10%). The combination of UFS with RCF in mortars provides the best results in terms of fluidity, strength, water absorption, and piezoresistive parameters. Generally, a lower mortar resistivity, even if with lower piezoresistivity properties, allows the use of cheaper instrumentation for SHM, thanks to the lower full scale and the better correlation strength between the change in resistivity with strain.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/317211

New Materials and Technologies for Durability and Conservation of Building Heritage
MATERIALS
Autore/i: Coppola, Luigi; Bellezze, Tiziano; Belli, Alberto; Bianco, Alessandra; Blasi, Elisa; Cappello, Miriam; Caputo, Domenico; Chougan, Mehdi; Coffetti, Denny; Coppola, Bartolomeo; Corinaldesi, Valeria; D’Amore, Alberto; Daniele, Valeria; Di Maio, Luciano; Di Palma, Luca; Donnini, Jacopo; Ferrara, Giuseppe; Filippi, Sara; Gastaldi, Matteo; Generosi, Nicola; Giosuè, Chiara; Incarnato, Loredana; Lamastra, Francesca; Liguori, Barbara; Macera, Ludovico; Maqbool, Qaisar; Cristina Mascolo, Maria; Mavilia, Letterio; Mazzoli, Alida; Medici, Franco; Mobili, Alessandra; Montesperelli, Giampiero; Pia, Giorgio; Redaelli, Elena; Ruello, Maria Letizia; Scarfato, Paola; Taglieri, Giuliana; Tittarelli, Francesca; Tulliani, Jean-Marc; Valenza, Antonino
Classificazione: 1 Contributo su Rivista
Abstract: The increase in concrete structures’ durability is a milestone to improve the sustainability of buildings and infrastructures. In order to ensure a prolonged service life, it is necessary to detect the deterioration of materials by means of monitoring systems aimed at evaluating not only the penetration of aggressive substances into concrete but also the corrosion of carbon-steel reinforcement. Therefore, proper data collection makes it possible to plan suitable restoration works which can be carried out with traditional or innovative techniques and materials. This work focuses on building heritage and it highlights the most recent findings for the conservation and restoration of reinforced concrete structures and masonry buildings.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/311867

Self-sensing mortars with recycled carbon-based fillers and fibers
Recent Advances in Concrete Technology and Sustainability Issues
Autore/i: Belli, Alberto; Mobili, Alessandra; Bellezze, Tiziano; Cachim, Paulo B.; Tittarelli, Francesca
Editore: American Concrete Institute SP-255
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This work investigates the potential of recycled carbon-based materials, obtained from industrial by-products, for the production of Multifunctional Cement-based Composites (MCC) with self-sensing behavior, usable in Structural Health Monitoring (SHM) systems. As recycled materials, Used Foundry Sand (UFS) and Recycled Carbon Fibers (RCF) have been chosen, whereas Graphene Nanoplatelets (GNP) and Virgin Carbon Fibers (VCF) have been selected as reference industrial fillers and fibers, respectively. Their effects on OPC-based mortars have been tested in terms of mechanical strength (compressive, flexural), durability (water absorption), microstructure (porosity), electrical and piezoresistive behavior (resistivity in static and under-load conditions). The results show that the combination of recycled fillers-fibers gives the best results in terms of workability, microstructure, strength, and durability. The worst compressive performances obtained with GNP are related to its hydrophobicity and the related problems in mixing. On the other hand, mixtures with UFS show a low electrical conductivity, but a high sensitivity to deformation (electrical strain-sensing). High-carbon by-products could be a functional, low-cost, and eco-friendly solution to produce high-performance and conductive concretes for self-monitoring systems.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/304780

Cement-Based Composites in Structural Health Monitoring
Recent Advances in Concrete Technology and Sustainability Issues
Autore/i: Tittarelli, Francesca; Mobili, Alessandra; Chiariotti, Paolo; Cosoli, Gloria; Giulietti, Nicola; Belli, Alberto; Pandarese, Giuseppe; Bellezze, Tiziano; Revel, Gian Marco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Concrete infrastructures, essential for the economic development of populations, require inspection and maintenance interventions to guarantee their functionality over time. These inspections are typically scheduled on a periodic basis but may not be sufficient to prevent the onset of deteriorations. When these problems occur, extraordinary maintenance operations shall be carried out, causing inconvenience to users and additional costs to normal management ones. The continuous monitoring of the infrastructures durability allows a paradigm shift in their management, allowing the transition from programmatic maintenance to the implementation of predictive maintenance strategies, with a consequent increase in the safety of the structures as well as a reduction in management costs. This work aims to provide a brief overview of continuous monitoring systems for concrete structures developed by Università Politecnica delle Marche, with particular focus on methods based on free corrosion potential measurement and electrical impedance spectroscopy
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/304781

Use of gasification char and recycled carbon fibres for sustainable and durable low-resistivity cement-based composites
JOURNAL OF BUILDING ENGINEERING
Autore/i: Mobili, Alessandra; Cosoli, Gloria; Bellezze, Tiziano; Revel, Gian Marco; Tittarelli, Francesca
Classificazione: 1 Contributo su Rivista
Abstract: In this paper, a newly developed cement and two recycled carbon-based materials, namely gasification char (GCH) and recycled carbon fibres (RCF), were used to manufacture new sustainable and low-resistivity cement-based composites. GCH was added at 0.5% and 1.0%, whereas RCF at 0.2%, on the total mortar volume. Microstructural, mechanical, electrical, and durability properties were studied. Results show that both additions decrease the electrical resistivity of mortars up to 90%, without impairing their mechanical properties. Moreover, they slightly reduce drying shrinkage and capillary water absorption of mortars, by decreasing total porosity and the average pore diameter, for the benefit of durability.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295728

Effect of Gasification Char and Recycled Carbon Fibres on the Electrical Impedance of Concrete Exposed to Accelerated Degradation
SUSTAINABILITY
Autore/i: Mobili, Alessandra; Cosoli, Gloria; Giulietti, Nicola; Chiariotti, Paolo; Pandarese, Giuseppe; Bellezze, Tiziano; Revel, Gian Marco; Tittarelli, Francesca
Classificazione: 1 Contributo su Rivista
Abstract: This paper aims to evaluate the effect of carbon-based conductive recycled additions, i.e., recycled carbon fibres (RCF) and gasification char (GCH), on the mechanical, electrical, and durability properties of concretes. The obtained results show that the compressive strength of concrete is not affected by conductive additions, whereas electrical impedance, measured according to Wenner’s method, is significantly reduced (6%, 30% and 74% with RCF, GCH, and their combination, respectively) to the advantage of self-sensing properties. As durability is concerned, conductive additions slightly increase capillary water absorption, whereas they decrease chloride ingress through diffusion and do not significantly modify carbonation resistance.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295207

Prototype experiments of the low voltage mineral deposition technology as eco-friendly solution for improving the sustainability of offshore platforms at the end of their production life
ENVIRONMENTAL TECHNOLOGY & INNOVATION
Autore/i: Colaleo, G.; Contestabile, P.; Bellezze, T.; Margheritini, L.; Dell'Anno, A.; Vicinanza, D.
Classificazione: 1 Contributo su Rivista
Abstract: Several oil and gas offshore platforms are approaching the end of their production life, thus requiring sounding sustainable management solutions. This study aimed to improve the current knowledge on the low voltage mineral deposition technology as an eco-friendly strategy to protect offshore platforms from corrosion and to create suitable substrates for the colonization and growth of sessile marine organisms, thus minimizing environmental impact due to metal release, supporting biodiversity and increasing ecological sustainability. To do so, experimental prototype structures were installed in the Ligurian Sea (NW Mediterranean Sea) with the aim to simulate the sub-merged parts of offshore platforms and to analyze over time (up to ca. 6 months), elemental and chemical composition, growth rates and corrosion protection ability of the minerals deposited on steel substrates, through the alkalization induced by cathodic polarization of the metal. The influence of operational (applied current density) and natural environmental parameters on the deposition process was investigated. Results of this experiment revealed that in general the mineral deposits were mainly composed by aragonite (CaCO3) and brucite (Mg(OH)2) and, more specifically, the amount of the latter prevails a little bit on the amount of the former. This result is most likely related to high cathodic polarization current densities reached during the experimentation. Despite brucite is expected to worsen the physical–mechanical​ characteristics of the mineral deposits, the overall deposits were able to protect to a certain extent the electrified steel material from corrosion. After about 6 months of induced mineral deposition, the layer over the steel reached the maximum thickness of about 2.4 mm, following a non-linear trend as a function of time, whereas the deposition rates ranged from 20.0 to 50.3 μm d−1, in relation with the applied current densities. At the same time, a positive relationship of the deposit grow rates with seawater temperature has been observed. Overall, the outcomes reported in this study provide new elements for the application of low voltage mineral deposition technology in temperate seas and pave the way for defining the best operating conditions to protect steel structures from corrosion and support biodiversity, thus contributing to the sustainability of the natural capital.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/312790

Nanoscale Characterization of Graphene Oxide-Based Epoxy Nanocomposite Using Inverted Scanning Microwave Microscopy
SENSORS
Autore/i: Joseph, C. H.; Luzi, Francesca; Azman, S. N. Afifa; Forcellese, Pietro; Pavoni, Eleonora; Fabi, Gianluca; Mencarelli, Davide; Gentili, Serena; Pierantoni, Luca; Morini, Antonio; Simoncini, Michela; Bellezze, Tiziano; Corinaldesi, Valeria; Farina, Marco
Classificazione: 1 Contributo su Rivista
Abstract: Scanning microwave microscopy (SMM) is a novel metrological tool that advances the quantitative, nanometric, high-frequency, electrical characterization of a broad range of materials of technological importance. In this work, we report an inverted near-field scanning microwave microscopy (iSMM) investigation of a graphene oxide-based epoxy nanocomposite material at a nanoscopic level. The high-resolution spatial mapping of local conductance provides a quantitative analysis of the sample's electrical properties. In particular, the electrical conductivity in the order of ∼10-1 S/m as well as the mapping of the dielectric constant with a value of ∼4.7 ± 0.2 are reported and validated by the full-wave electromagnetic modeling of the tip-sample interaction.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/309543

Pitting corrosion and mechanical resistance of 441 stainless steel pipes used in the production of condensing boilers
LA METALLURGIA ITALIANA
Autore/i: Vicere, A.; Forcellese, P.; Rossi, M.; Amicucci, L.; Ferretti, P.; Bellezze, T.
Classificazione: 1 Contributo su Rivista
Abstract: In this work, pitting corrosion resistance and mechanical tensile strength were evaluated for type 441 stainless steel pipes used to produce "spiral"-shaped heat exchangers for condensing boilers. Samples were obtained from untreated pipes and in-line annealing treated pipes at temperatures of 700, 800 and 900 °C. Pitting corrosion resistance was evaluated by cyclic potentiodynamic anodic curves in a three-electrodes electrochemical cell containing an aqueous solution of NaCl at room temperature and having a chloride concentration of 0.05 wt%. Mechanical tensile strength was evaluated by means of tests carried out on straight tubes. Electrochemical experimental results show that localized corrosion resistance is higher in annealed stainless steel as the treatment temperature increases. The tensile tests confirmed that an increase of 441 ductility has been observed, especially at high temperatures.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/312791

Study of the localized corrosion resistance of AA5083 aluminium alloy subjected to severe plastic deformation
LA METALLURGIA ITALIANA
Autore/i: Vicere, A.; Cabibbo, M.; Forcellese, P.; Giuliani, G.; Bellezze, T.
Classificazione: 1 Contributo su Rivista
Abstract: In this work the localized corrosion behaviour of AA5083 aluminium alloy, subjected to severe plastic deformation (SPD) through the Equal Channel Angular Pressing technique (ECAP), useful to obtain an ultrafine microstructure, was studied. This process improves mechanical properties and modifies the microstructure of the alloy. With more details, the localized corrosion resistance of the AA5083 alloy subjected to thermal and cryogenic treatments and finally to ECAP was evaluated. Electrochemical characterization of this alloy was performed in aqueous solution 0.1 M of NaCl and pH 6.5, at room temperature, by means of cyclic potentiodynamic polarizations and potentiostatic polarizations for evaluating metastable pitting events. All tests were performed in deaerated conditions. The experimental results show that ECAP tends to increase AA5083 alloy localized corrosion susceptibility.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/312793

Investigation on Corrosion Resistance Properties of 17-4 PH Bound Metal Deposition As-Sintered Specimens with Different Build-Up Orientations
METALS
Autore/i: Forcellese, Pietro; Mancia, Tommaso; Simoncini, Michela; Bellezze, Tiziano
Classificazione: 1 Contributo su Rivista
Abstract: Additive manufacturing is a promising and emerging technology that can transform the global manufacturing and logistics by cutting costs and times of production. Localized corrosion resistance properties of 0°, 45°, and 90° build-up orientations of 17-4 PH as-sintered samples, manufactured by means of Bound Metal Deposition (BMD), have been investigated by electrochemical and morphological investigations. The cyclic potentiodynamic polarization curves and the open circuit potential monitoring, together with potential drop analysis, revealed that the BMD localized corrosion resistance properties were lowered if compared to a wrought 17-4 PH: a characteristic anodic behavior and many drops in potential were recorded for BMD, whilst the wrought specimens presented a typical passive behavior with pitting corrosion. Morphological investigations by scanning electron microscopy and energy-dispersive X-ray analysis revealed the presence of porosities and defects, especially for the 90° build-up orientation, and inclusions of SiO2. The 45° build-up orientation showed the best corrosion resistance properties among all the BMD specimens, even though defects and porosities were observed, suggesting that their morphology and geometry influenced the overall corrosion behavior.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/307563

Solutions of Critical Raw Materials Issues Regarding Iron-Based Alloys
MATERIALS
Autore/i: Novak, P.; Bellezze, T.; Cabibbo, M.; Gamsjager, E.; Wiessner, M.; Rajnovic, D.; Jaworska, L.; Hanus, P.; Shishkin, A.; Goel, G.; Goel, S.
Classificazione: 1 Contributo su Rivista
Abstract: The Critical Raw Materials (CRMs) list has been defined based on economic importance and supply risk by the European Commission. This review paper describes two issues regarding critical raw materials: the possibilities of their substitution in iron-based alloys and the use of iron-based alloys instead of other materials in order to save CRMs. This review covers strategies for saving chromium in stainless steel, substitution or lowering the amounts of carbide-forming elements (especially tungsten and vanadium) in tool steel and alternative iron-based CRM-free and low-CRM materials: austempered ductile cast iron, high-temperature alloys based on intermetallics of iron and sintered diamond tools with an iron-containing low-cobalt binder.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/291517

Corrosion behaviour of galvanized steel in cement- and geopolymer-based concrete: a review on scientific work at the Polytechnic University of Marche
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Autore/i: Bellezze, Tiziano; Mobili, Alessandra; Tittarelli, Francesca
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Hot-dip galvanized steel rebars are effective to increase the durability of reinforced construction materials, based on traditional cement and on recently studied alkali-activated binders, such as geopolymers. Instead of steel reinforcements, galvanized reinforcements in concrete are protected by calcium hydroxyzincate (CaHZn) layer, which, under carbonation, transforms into a less protective hydrozincite (HZ), but corrosion resistant layer. In the case of chlorides ingress, the threshold for localized corrosion initiation is at least three times higher for galvanized rebars than for steel rebars: 1.3 wt% vs 0.4 wt%, respectively, with respect to the weight of cement. Therefore, galvanized rebars increase considerably the durability of reinforced concrete structures, without significantly impairing construction costs. Concerning geopolymers, the matrix is more alkaline than the traditional cementitious ones and the scarce presence of calcium ions cannot guarantee the protection of galvanized steel by CaHZn. Actually, also in these conditions, galvanized steel passivates even if with a certain delay (4-7 days) from the cast, by the formation of ZnO passive layer. In particular, geopolymers obtained by fly ash slow the ingress of chlorides, protecting the reinforcements, if galvanized, from a penetrating localized corrosion of Zn-Fe alloys.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/290023

Atmospheric corrosion behaviour of zinc and zinc alloys: comparison between natural and accelerated exposure
Digital Proceedings of CORROSION 2021
Autore/i: Bolzoni, F.; Beretta, S.; Bellezze, T.; Ormellese, M.
Editore: AMPP-Association for Materials Protection and Performance
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Atmospheric corrosion of galvanized steel is a well-known subject: many experimental results, international research programs, as ISOCORRAG and MICAT, and ISO standards are available. In some applications, as in the case of gabion walls, Zn-Al alloys coatings have been proposed to protect steel wires. These coatings, as a function of thickness and severity of the environment, should guarantee a service life in the range 10 to 120 years. Aim of this paper is to compare the corrosion rate of pure zinc and Zn-Al alloys, in accelerated exposure tests and in natural atmosphere for medium-long time exposure. Obtained data were matched with the prediction suggested by the standards. The results showed that the corrosion rate of zinc alloys is lower than zinc, in both natural and accelerated exposure. The lack of medium-long term data in natural exposure makes difficult, if not impossible, to forecast the real behavior of zinc alloys, especially in very severe exposure conditions (as condition C3 according to ISO 9223).
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295121

Resistenza a corrosione per pitting e resistenza meccanica di tubi in acciaio inossidabile 441 utilizzati per la produzione di scambiatori di calore nelle caldaie a condensazione
Atti della XIV edizione delle Giornate Nazionali sulla Corrosione e Protezione, Virtual Edition
Autore/i: Viceré, A.; Forcellese, P.; Bellezze, T.; Rossi, M.; Amicucci, L.; Ferretti, P.
Editore: Associazione Italiana di Metallurgia - MIlano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In questo lavoro è stata studiata la resistenza a corrosione per pitting e la resistenza meccanica di tubi in acciaio inossidabile tipo 441 impiegati per la produzione di scambiatori di calore “a spirale” per caldaie a condensazione. I campioni esaminati sono stati ricavati da tubi non trattati e da tubi sottoposti a ricottura in linea alle temperature di 700, 800 e 900 °C. La corrosione per pitting è stata valutata attraverso curve anodiche potenziodinamiche cicliche in una cella elettrochimica a tre elettrodi contenente una soluzione acquosa con concentrazione di cloruri di 0,05% in peso. La resistenza meccanica è stata valutata attraverso prove di trazione dei tubi rettilinei. I risultati sperimentali evidenziano che la resistenza a corrosione localizzata è migliore nell’acciaio ricotto all’aumentare della temperatura di ricottura, mentre dalle prove di trazione si è osservato un aumento della duttilità del materiale, soprattutto alle temperature più elevate.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295147

Studio della resistenza a corrosione localizzata della lega di alluminio AA5083 sottoposta a deformazione plastica severa
Atti della XIV edizione delle Giornate Nazionali sulla Corrosione e Protezione, Virtual Edition
Autore/i: Viceré, A.; Cabibbo, M.; Forcellese, P.; Giuliani, G.; Bellezze, T.
Editore: Associazione Italiana di Metallurgia - MIlano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In questo lavoro è stato studiato il comportamento a corrosione localizzata della lega di alluminio AA5083, sottoposta a deformazione plastica severa (SPD) attraverso la tecnica dell’Equal Channel Angular Pressing (ECAP), utile a ottenere una microstruttura ultrafine. Questo tipo di processo migliora le proprietà meccaniche della lega e modifica la sua microstruttura. In particolare, è stata analizzata la resistenza a corrosione localizzata della lega AA5083 sottoposta a trattamenti termici e trattamento criogenico e infine al processo ECAP. La caratterizzazione elettrochimica di questa lega è stata effettuata in una soluzione acquosa alla concentrazione di cloruri pari a 0,1 M e pH 6,5, a temperatura ambiente, attraverso polarizzazioni potenziodinamiche cicliche e polarizzazioni potenziostatiche per valutare gli eventi di pitting metastabile. Tutti i test sono stati eseguiti in condizioni deaerate. I risultati ottenuti mostrano che l’ECAP tende ad aumentare la suscettibilità alla corrosione localizzata della lega AA5083.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295146

Durability benefits of galvanized steel in reinforced concrete under different exposure conditions
Capacity Assessment of Corroded Reinforced Concrete Structure
Autore/i: Bellezze, Tiziano; Mobili, Alessandra; Tittarelli, Francesca
Editore: Collegio dei Tecnici della Industrializzazione Edilizia (cte) and Fédération International du Béton (fib)
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper is a short review of the work performed for many years at the Polytechnic University of Marche on the use of hot-dip galvanized steel rebars in reinforced concrete, for increasing its durability without significantly impairing the installation costs. Corrosion research was done in traditional cementitious matrixes and in geopolymeric ones. Compared to black steel rebars, these studies clearly show that passivation of galvanized steel ones plays a key role on their protection, when exposed to severe conditions: contamination of chlorides (higher concentration thresholds before the onset of localized corrosion) and/or carbonation (formation of a new passive layer).
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/294887

TC CORROSION
LA METALLURGIA ITALIANA
Autore/i: Bolzoni, F; Cabrini, M; Bellezze, T; Brenna, A; Fedrizzi, L; Frigo, M; Gabetta, G; Gastaldi, M; Monetta, T; Pezzato, L; Rollet, S; Traverso, P
Classificazione: 1 Contributo su Rivista
Abstract: Comitato Tecnico di Corrosione in seno all'Associazione Italiana di Metallurgia (Milano): descrizione della storia e delle attività sia scientifiche che divulgative/formative.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295148

Mechanical, durability, depolluting and electrical properties of multifunctional mortars prepared with commercial or waste carbon-based fillers
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Mobili, Alessandra; Belli, Alberto; Giosue', Chiara; Pierpaoli, Mattia; Bastianelli, Luca; Mazzoli, Alida; Ruello, Maria Letizia; Bellezze, Tiziano; Tittarelli, Francesca
Classificazione: 1 Contributo su Rivista
Abstract: Carbon-based fillers from industrial wastes and commercial ones were compared to improve the properties of lime-based mixes. As commercial fillers, graphene nanoplatelets and activated carbon were used, whereas as industrial wastes a char obtained by the gasification of biomasses and a used foundry sand were chosen. Carbon-based wastes were found to be a good cost-effective alternative to commercial carbon based fillers to increase the compressive strength (of about 25%) and to reduce water capillary absorption (of about 50%) thanks to the paste refinement; to enhance depollution capacity (of about 25%) and increase both electrical conductivity (up to 65%) and electromagnetic shielding effectiveness (of about 6%) of the hardened compounds thanks to the carbon content.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/288423

Performance of concretes manufactured with newly developed low-clinker cements exposed to water and chlorides: Characterization by means of electrical impedance measurements
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Cosoli, G.; Mobili, A.; Giulietti, N.; Chiariotti, P.; Pandarese, G.; Tittarelli, F.; Bellezze, T.; Mikanovic, N.; Revel, G. M.
Classificazione: 1 Contributo su Rivista
Abstract: This paper discusses the electrical impedance behaviour, measured according to the Wenner’s method, of three different concrete mixes during accelerated degradation tests. Being a first attempt to move from laboratory to in-field applications targeted to long-term monitoring, the same electrode array configuration and set-up (AC current at 10 kHz) is used. Results show that electrical impedance decreases down to 24% in capillary water absorption tests, 77% and 86% in salt-spray chamber and wet/dry cycles with 3.5% NaCl solution, respectively. The two new low-clinker cements adopted seem to improve the measurement sensitivity towards contaminants ingress with respect to the commercial one (reference).
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295120

A Comparative Evaluation of Nanohydroxyapatite-Enriched Hydrogen Peroxide Home Bleaching System on Color, Hardness and Microstructure of Dental Enamel
MATERIALS
Autore/i: Monterubbianesi, Riccardo; Tosco, Vincenzo; Bellezze, Tiziano; Giuliani, Giampaolo; Özcan, Mutlu; Putignano, Angelo; Orsini, Giovanna
Classificazione: 1 Contributo su Rivista
Abstract: This study aimed to evaluate two hydrogen peroxide (HP)-based at-home bleaching systems in order to analyze whether nano-hydroxyapatite (nHA) addition may represent a reliable and safe solution for tooth whitening without altering dental microstructure and hardness. Human third molars (N = 15) were treated with two bleaching agents, one containing 6%HP (6HP) and the other 6% HP nHA-enriched (6HP-nHA) with average particle diameter ranging from 5–20 nm. Their effects on enamel were assessed using a spectrophotometer, Vickers microhardness (VMH) test and Scanning Electron Microscopy (SEM), comparing the treated groups with the non-treated control group (CTR). Color analysis revealed improvement in whiteness in both groups compared to CTR. VMH test results showed no differences among the groups. SEM analysis highlighted no evident changes in the enamel microstructure of tested groups compared to CTR. At high magnification, in 6HP group, a slight increase in irregularities of enamel surface morphology was observed, while 6HP-nHA group displayed removal of the aprismatic layer but preservation of the intact prismatic structure. These results suggest that the 6HP-nHA agent may be recommended to provide reliable whitening treatment, without damaging the enamel micromorphology and hardness
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/292352

Gasification Char and Used Foundry Sand as Alternative Fillers to Graphene Nanoplatelets for Electrically Conductive Mortars with and without Virgin/Recycled Carbon Fibres
APPLIED SCIENCES
Autore/i: Mobili, Alessandra; Giosue', Chiara; Bellezze, Tiziano; Revel, Gian Marco; Tittarelli, Francesca
Classificazione: 1 Contributo su Rivista
Abstract: Structural health monitoring to assess the safety, durability and performance of structures can be performed by non-destructive methods such as the measurement of impedance in self-sensing cement-based elements. Cement-based materials, like mortars and concretes, generally have high electrical resistivity but the addition of carbon-based fillers and fibres decreases their electrical resistivity and thus enhances their self-sensing capabilities. In this study, two waste carbon-based fillers, namely, used foundry sand and gasification char were compared to commercial graphene nanoplatelets and used to produce self-sensing cement mortars, both with and without recycled or virgin carbon fibres. The mortars were tested in terms of their mechanical and electrical properties as well as their propensity to capillary water absorption. The results demonstrate that gasification char alone is the best carbonaceous waste for decreasing the electrical resistivity (-42%) and water absorption (-17%) of mortars, while their compressive strength remains unaltered. Moreover, although there is a slight reduction in compressive strength and an increase in water suction when gasification char is coupled with fibres, the combination of fillers and fibres has a synergistic effect in decreasing mortars’ electrical resistivity, especially when recycled carbon fibres are used (-80%).
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/286345

Sistemi innovativi per il monitoraggio della durabilità delle infrastrutture
INGENIO
Autore/i: Tittarelli, Francesca; Chiariotti, Paolo; Mobili, Alessandra; Cosoli, Gloria; Giulietti, Nicola; Pandarese, Giuseppe; Bellezze, Tiziano; Revel, Gian Marco
Classificazione: 1 Contributo su Rivista
Abstract: Le infrastrutture in calcestruzzo costituiscono uno dei punti cardine per lo sviluppo economico delle popolazioni. Tuttavia, esse richiedono interventi di ispezione e manutenzione che ne garantiscano la funzionalità nel tempo. Tali ispezioni sono tipicamente programmate con cadenze periodiche, ma possono non essere sufficienti a prevenire l’insorgere di problemi legati alla loro durabilità. Quando questi si verificano occorre infatti eseguire interventi di manutenzione straordinaria che comportano disagi per gli utenti e costituiscono una voce di costo aggiuntiva rispetto ai normali costi di gestione. Il monitoraggio continuo della durabilità delle infrastrutture permette un cambio di paradigma nella loro gestione, consentendo il passaggio da una manutenzione programmatica all’attuazione di strategie di manutenzione predittiva, con un conseguente incremento della sicurezza della struttura nonché una riduzione dei costi di gestione. Questo lavoro ha come obbiettivo quello di fornire una breve panoramica sui sistemi di monitoraggio della durabilità di strutture in calcestruzzo armato sviluppati dall’Università Politecnica delle Marche, con particolare focus sui metodi di misura del potenziale di libera corrosione e della spettroscopia di impedenza elettrochimica.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/285565

Comportamento a corrosione di armature in acciaio e acciaio zincato in una malta ad attivazione alcalina a base di metacaolino dopo carbonatazione accelerata
LA METALLURGIA ITALIANA
Autore/i: Mobili, A.; Giosuè, C.; Bellezze, T.; Tittarelli, F.
Classificazione: 1 Contributo su Rivista
Abstract: Il lavoro presenta il comportamento a corrosione di armature in acciaio e acciaio zincato immerse in malte ad attivazione alcalina a base di metacaolino e malte tradizionali cementizie appartenenti alla stessa classe di resistenza meccanica (classe R3 con Rc ≥ 25 MPa, secondo la UNI EN 1504-3). I test sono stati effettuati valutando il potenziale di libera corrosione e la resistenza alla polarizzazione durante il primo mese di stagionatura e durante i successivi cicli settimanali di bagnasciuga in acqua dopo esposizione in camera al 3% di CO2. Durante la stagionatura, l’elevato pH della malta in metacaolino rallenta il raggiungimento dello stato passivo delle armature zincate che, successivamente, raggiungono resistenze di polarizzazione paragonabili alle barre immerse nella malta cementizia. Durante carbonatazione accelerata, il pH della malta in metacaolino si abbassa più velocemente di quello della malta cementizia. Durante i cicli di bagnasciuga, entrambe le tipologie di armatura mostrano simili resistenze alla polarizzazione in entrambe le matrici studiate.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/280364

Commercial and recycled carbon/steel fibers for fiber-reinforced cement mortars with high electrical conductivity
CEMENT & CONCRETE COMPOSITES
Autore/i: Belli, Alberto; Mobili, Alessandra; Bellezze, Tiziano; Tittarelli, Francesca
Classificazione: 1 Contributo su Rivista
Abstract: The paper aims to provide a comprehensive study on the compositional optimization of high-conductive multifunctional fiber-reinforced cement mortars (FRCMs). Therefore, the effects of three different fiber types: virgin carbon fibers (VCFs), recycled carbon fibers (RCFs), and brass-plated steel fibers (BSFs), added at a broad range of concentrations, as 0.05%, 0.1%, 0.2%, 0.4%, 0.8%, 1.2%, and 1.6% by volume, on the mechanical, electrical and durability properties of FRCMs have been compared. The results showed that RCFs increase the flexural and tensile splitting strength up to 100%, whereas BSFs improve the compressive strength by 38%. Moreover, the fibers decrease both the capillary water absorption and the drying shrinkage by 39%. Electrical conductivity tests show that RCFs decrease the electrical resistivity of mortars up to one order of magnitude, in addition to a percolation threshold between 0.1 and 0.2 vol%.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/275078

Corrosion resistance of Zn-Ni coatings containing ZrO2 nanoparticles
Porceedings of EUROCORR 2019 (European Federation of Corrosion Event No. 445)
Autore/i: Roventi, G.; Viceré, A.; Bellezze, T.
Editore: Sociedad Española des Materiales (SOCIEMAT), Madrid (Spain)
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Corrosion resistance of Zn-Ni-ZrO2 nanocomposite coatings was studied. Zn-Ni alloy was electrodeposited on mild steel substrate from an alkaline bath used by galvanic industry (Atotech). ZnNi-ZrO2 nanocomposite coatings were obtained by adding to the deposition bath 10 g L-1 of yttria stabilized ZrO2 nanoparticles (Aldrich, particle size < 100 nm, 10.14 wt% Y2O3). Electrodepositions were carried out at 25±1 °C under constant magnetic stirring and under galvanostatic control (current density: 30 mA cm-2). Homogeneous and compact coatings with low grain size have been obtained. All the electrodeposited alloys are constituted by cubic γ phase Ni5Zn21; the incorporation of ZrO2 nanoparticles does not change the orientation of γ phase. The ZrO2 content of the coatings was 1.2 wt%; the incorporation of zirconia nanoparticles does not lead to a change in the morphology. Corrosion resistance of both Zn-Ni and Zn-Ni-ZrO2 coatings was studied by means of polarization resistance measurements, potentiodynamic polarizations and electrochemical impedance spectroscopy performed at room temperature in 3.5 % NaCl solution. The obtained results indicate that, under the experimental conditions of this work, ZrO2 incorporation leads to a slight improvement in corrosion resistance of Zn-Ni alloy. EIS measurements, performed at different immersion times, show an increase in corrosion resistance with the time, due to the formation of a uniform and compact layer of Zn5(OH)8Cl2.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/271365

Piezoresistive behaviour of mortars loaded with graphene and carbon fibers for the development of self-sensing composites
Advances and Trends in Engineering Sciences and Technologies III
Autore/i: Belli, A.; Mobili, A.; Bellezze, T.; Tittarelli, F.; Cachim, P. B.
Editore: Taylor & Francis Group
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In recent years, infrastructures have become of primary importance for society and for the economic development. This led to the introduction of monitoring systems for their protec-tion, and for an eco-friendly saving of resources for their maintenance. In the field of rein-forced concrete, there is a growing interest for the introduction of conductive cement-based composites for monitoring the health of structures through the evaluation of their electronic parameters. In this work, resistivity and piezoresistivity of mortars added with graphene nano-platelets (GNP), and carbon fibers (CF) were evaluated. The variations in electrical resistivity as a function of strain were analyzed under cyclic uniaxial compression of the mortars sam-ples. The results shown a high piezoresistivity behavior of the mortars with an optimal disper-sion of GNP and CF, with a quite reversible relation between fractional change in resistivity (FCR) and compressive strain.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/264704

CARBON-BASED FILLERS AND FIBERS FOR ELECTRICALLY CONDUCTIVE CEMENT MORTARS
XV CONVEGNO NAZIONALE AIMAT - XII CONVEGNO INSTM SULLA SCIENZA E TECNOLOGIA DEI MATERIALI
Autore/i: Mobili, A.; Bellezze, T.; Revel, Gm; Tittarelli, F.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269307

Studio del comportamento a corrosione di campioni di alluminio AA5083 sottoposti a ECAP e trattamento criogenico
Atti della XIII edizione delle Giornate Nazionali sulla Corrosione e Protezione
Autore/i: Viceré, A.; Cabibbo, M.; Roventi, G.; Bellezze, T.
Editore: Associazione Italiana di Metallurgia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In questo lavoro è stato studiato il comportamento a corrosione della lega di alluminio AA5083 (Al-Mg), sottoposta inizialmente a un trattamento termico di solubilizzazione (380°C per 1h) e poi a una deformazione plastica severa (SPD), attraverso la tecnica dell’Equal Channel Angular Pressing (ECAP). Alcuni campioni sono stati sottoposti prima del processo ECAP a trattamento criogenico. Lo scopo della sperimentazione è stato quello di effettuare una caratterizzazione elettrochimica della lega di alluminio, valutando l’influenza dell’affinamento dei grani ottenuto tramite ECAP e dei trattamenti di solubilizzazione e criogenico sul comportamento a corrosione del materiale. L’analisi della resistenza a corrosione dei vari campioni AA5083 è stata eseguita a temperatura ambiente mediante test elettrochimici (polarizzazione potenziodinamica e misure di impedenza elettrochimica) in una soluzione acquosa a 0,1 M Cl- a pH 2. Dai risultati sperimentali è emerso che in queste condizioni il comportamento a corrosione dei vari campioni risulta molto simile tra loro e di conseguenza né il trattamento criogenico, né l’affinamento prodotto dall’ECAP determinano cambiamenti della resistenza a corrosione della lega.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/271227

Comportamento a corrosione di armature in acciaio e acciaio zincato in una malta ad attivazione alcalina a base di metacaolino dopo carbonatazione accelerata
Atti della XIII edizione delle Giornate Nazionali sulla Corrosione e Protezione
Autore/i: Mobili, A.; Giosuè, C.; Bellezze, T.; Tittarelli, F.
Editore: Associazione Italiana di Metallurgia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The work presents the corrosion behavior of bare and galvanized steel rebars embedded in metakaolin alkali-activated mortar and traditional cement-based mortar belonging to the same mechanical strength class (R3 class with Rc ≥ 25 MPa, according to UNI EN 1504-3). Tests were conducted evaluating both the corrosion potential and the polarization resistance throughout the first month of curing and during the subsequent weekly wet/dry cycles in tap water after exposure to a chamber with 3% of CO2. During the first month, the high alkalinity of alkali-activated mortar delays the achievement of the passive state in particular for galvanized steel rebars, even though, after that period, they reach the same polarization resistance of those embedded in the cement-based mortar. During accelerated carbonation, the neutralization of alkalinity in alkali-activated mortar occurs more quickly than in cement-based mortar. During exposure to wet/dry cycles in tap water, both bare and galvanized steel rebars show comparable polarization resistance values in both studied mortars.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/271226

Corrosion response of ultrafine-grained aluminium alloy processed by ECAP
Porceedings of EUROCORR 2019 (European Federation of Corrosion Event No. 445)
Autore/i: Viceré, A.; Cabibbo, M.; Roventi, G.; Bellezze, T.
Editore: Sociedad Española des Materiales (SOCIEMAT)
Luogo di pubblicazione: Madrid
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Equal-channel angular pressing (ECAP) is one of Severe Plastic Deformation (SPD) techniques used to achieve ultrafine-grained materials in order to enhance mechanical properties of these materials. However, the deformation induced by these techniques generally deteriorate the material corrosion due to the modifications produced on its microstructure. In this study, the corrosion response of AA6012 aluminium alloy subjected to cryogenic and different heat treatments (solubilization and artificial aging) and then processed by ECAP was investigated. Electrochemical characterizations of this alloy in two different aerated and deaerated aqueous solutions at the same chloride concentrations (0.1 M NaCl) but at different pH (pH 2 and pH 6.5) were carried out by means of potentiodynamic polarization and electrochemical impedance spectroscopy. Before electrochemical tests, all specimens were embedded in an epoxy resin and subsequently some of them grinded with emery papers up to 4000 grit and others also polished with alumina (1 µm). SEM and TEM analyses were performed to study the evolution of the microstructure and the surface composition. The results show that in absence of aging, ECAP and cryogenic treatment influenced the corrosion behaviour of the AA6012 alloy. On the contrary the alloy subjected to artificial aging showed similar corrosion response.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/271369

Sustainability in Construction Materials: From Waste Valorization to Circular Economy
The First Outstanding 50 Years of “Università Politecnica delle Marche”
Autore/i: Ruello, Maria Letizia; Bellezze, Tiziano; Corinaldesi, Valeria; Donnini, Jacopo; Eusebi, Anna Laura; Fatone, Francesco; Fava, Gabriele; Favoni, Orlando; Fratesi, Romeo; Giosue', Chiara; Giuliani, Giampaolo; Marcellini, Mirco; Mazzoli, Alida; Mobili, Alessandra; Roventi, Gabriella; Tittarelli, Francesca
Editore: Springer
Luogo di pubblicazione: Cham
Classificazione: 2 Contributo in Volume
Abstract: Already from the beginning, 50 years ago, the first nucleus of researchers establishing the research group, was convinced that the construction sector was the best option for the valorization of industrial by-products as “secondary raw materials”. In fact, this sector is probably the largest consumer of resources and the largest waste generator, consequently it has huge environmental impact. On the other hand, construction materials affect the performance of buildings with respect to safety, health, environmental performance and energy efficiency. Manufacturing of construction products using alternative raw materials; recycling to manage construction and demolition waste; durability and environmental compatibility of materials: all these were the different and challenging fields of research that the group has faced in a continuous effort of innovation and cooperation at national and international level. The focus of the group was already perfectly in line with what is now called “Circular Economy”, which at present is considered a revolution in the way of human economic development. We are sure the group thus contributed to this revolution even before the term was in current use. We feel ready for the next 50.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272692

Investigation of the Effects of Mold Temperature, Test Temperature and Strain Rate on Mechanical Behaviour of Polypropylene
JOURNAL OF DYNAMIC BEHAVIOR OF MATERIALS
Autore/i: Farotti, E.; Mancini, E.; Bellezze, T.; Sasso, M.
Classificazione: 1 Contributo su Rivista
Abstract: This paper investigates the time and temperature dependence of a ductile polymer, polypropylene, from the mechanical point of view. As the polymeric specimens have been manufactured by the injection molding process, the influence of mold temperature has been also subjected to the study. Compression tests have been performed both in quasi static and dynamic range (10–3/103 s−1), at different test temperatures (− 20/40 °C), and the results have been analysed in terms of yield stress and failure behaviour. The strength of the polymer is strongly influenced from all the input parameters. Mold temperature has a relevant effect only at room and high temperature. Polypropylene reveals a ductile to brittle transition when it is loaded at high rates, except when test temperature is high. The relation between test temperature, strain rate and yield stress is found to be well described by the Ree–Eyring model, adapted to the two relaxation mechanisms involved.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/278162

Study of the corrosion behaviour of AA5083 aluminium samples subjected to ECAP and cryogenic treatment
LA METALLURGIA ITALIANA
Autore/i: Vicere, A.; Cabibbo, M.; Roventi, G.; Bellezze, T.
Classificazione: 1 Contributo su Rivista
Abstract: In this work the corrosion behaviour of AA5083 aluminium alloy (Al-Mg), initially subjected to a heat treatment of solubilization (380°C for 1h) and then to a severe plastic deformation (SPD), through the Equal Channel Angular Pressing (ECAP), was studied. Some samples were subjected to cryogenic treatment before the ECAP process. The aim of this experimentation was to carry out an electrochemical characterization of the aluminium alloy, evaluating the influence of grain refinement obtained by ECAP and of solubilization and cryogenic treatments on the corrosion behaviour of the material. The analysis of the corrosion resistance of the different samples was performed at room temperature by means of electrochemical tests (potentiodynamic polarization and electrochemical impedance spectroscopy tests) in an aqueous solution at 0.1 M Cl- at pH 2. The experimental results show that in these conditions, the corrosion behaviour of the different samples is more or less the same and consequently neither the cryogenic treatment nor the refinement produced by ECAP influence the corrosion resistance of the alloy.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/273443

Corrosion behavior of AA6012 aluminum alloy processed by ECAP and cryogenic treatment
METALS
Autore/i: Vicere, A.; Roventi, G.; Paoletti, C.; Cabibbo, M.; Bellezze, T.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/271225

Study of stainless steels corrosion in a strong acid mixture. Part 1: cyclic potentiodynamic polarization curves examined by means of an analytical method
CORROSION SCIENCE
Autore/i: Bellezze, Tiziano; Giuliani, Giampaolo; Roventi, Gabriella
Classificazione: 1 Contributo su Rivista
Abstract: The corrosion resistance of AISI 316L, AISI 904L, Sanicro 28, SAF 2205, SAF 2507 and SAF 2707 was studied in an acid mixture containing tartaric acid saturated solution, H2SO4 and HCl, as a function of temperature (22–60 °C) and alloys composition. The stainless steels were examined through anodic polarization curves; an analytical method is proposed to obtain the characteristic parameters from these curves. The results indicate that Cr and Mo play the most important role on the active-passive transition of the tested alloys. AISI 904L, Sanicro 28 and SAF 2707 showed the best anodic characteristics among the examined stainless steels.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/252858

STUDIO DEGLI EFFETTI DELL’ACCOPPIAMENTO GALVANICO TRA ARMATURE ZINCATE E CASSERI METALLICI NEL CALCESTRUZZO FRESCO
STRUCTURAL
Autore/i: Bellezze, Tiziano; Barbaresi, Elisa; Vicere', Annamaria; Roventi, Gabriella
Classificazione: 1 Contributo su Rivista
Abstract: In the present work, the phenomenon of hydrogen evolution on the surface of the steel moulds, used to obtain concrete manufactured products reinforced with galvanized rebars, has been investigated. The galvanic coupling between the moulds and the galvanized reinforcements, in the fresh concrete just after the cast, leads to a large amount of hydrogen bubbles evolution on the external surface of the manufactured product, which will be characterized by a high roughness. In many cases, it can be a problem for manufacturers of these products. In order to study this phenomenon and to evaluate it quantitatively, a formwork in a reduced scale was built for simulating a prefabricated real beam. It was equipped with a mould formed by "segmented" steel walls of which, by means of an electric circuit suitably realized, the partial currents and local potentials for each segment were measured. Furthermore, the potential and the current of the macrocouple relative to the galvanized bars were also monitored. From the electrochemical measurements and the observations made on the surface of the manufactured product at the end of the experimentation, it was found that the hydrogen evolution mainly affects the area of the mould directly facing the galvanized bars, leading to a significant roughness of the concrete surface in contact with this area.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/271224

Possible alternatives to critical elements in coatings for extreme applications
IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING
Autore/i: Grilli, MARIA LUISA; Valerini, Daniele; Piticescu, RADU ROBERT; Bellezze, Tiziano; Yilmaz, Mehmet; Rinaldi, Antonio; CUESTA LOPEZ, Santiago; Rizzo, Antonella
Classificazione: 1 Contributo su Rivista
Abstract: Surface functionalisation and protection have been used since a long time for improving specific properties of materials such as lubrication, water repellence, brightness, and for increasing durability of objects and tools. Among the different kinds of surface treatments used to achieve the required properties, the use of coatings is fundamental to guarantee substrate durability in harsh environments. Extreme working conditions of temperature, pressure, irradiation, wear and corrosion occur in several applications, thus very often requiring bulk material protection by means of coatings. In this study, three main classes of coatings used in extreme conditions are considered: i) hard and superhard coatings for application in machining tools, ii) coatings for high temperatures (thermal barrier coatings), and iii) coatings against corrosion. The presence of critical elements in such coatings (Cr, Y, W, Co, etc.) is analysed and the possibility to use CRMs-free substitutes is reviewed. The role of multilayers and nanocomposites in tailoring coating performances is also discussed for thermal barrier and superhard coatings.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/266365

Effect of soluble inhibitors on the corrosion behaviour of galvanized steel in fresh concrete
CEMENT AND CONCRETE RESEARCH
Autore/i: Bellezze, T.; Timofeeva, D.; Giuliani, G.; Roventi, G.
Classificazione: 1 Contributo su Rivista
Abstract: The effect of some soluble inhibitors on the passivation time of galvanized steel reinforcements in fresh concrete was studied in order to reduce H2 evolution associated with the active corrosion. The investigation was performed by means of corrosion potential monitoring, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. The obtained results indicate that the passivation of galvanized steel in concrete containing chromates occurs in three steps with different mechanisms and that dissolved oxygen is necessary for the beginning of passivation process. Among the inhibitors studied as alternative to Cr VI, nitrite seem the most promising one, even if it is less effective than chromate. Diethanolamine and molybdate ions do not have significant effect on the passivation time of galvanized steel in fresh concrete.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/256267

Thermo-structural analysis of components in ceramic material
PROCEDIA STRUCTURAL INTEGRITY
Autore/i: Chiappini, G.; Sasso, M.; Bellezze, T.; Amodio, D.
Classificazione: 1 Contributo su Rivista
Abstract: The aim of this paper is the systematic study of thermo-structural behavior of ceramic components, in particular, mixtures of refractory materials with high thermal and mechanical performance. Using 3-point bending tests, the elastic modulus, ultimate stress and elongation was obtained; measured values, also thanks to the use of DIC optical technology, was correlated with the different thickness and specific weight values of the specimens used. In order to characterize the thermal behavior, thermal conductivity and specific heat were measured. The experimentally determined average values of such thermomechanical properties have been used in FEM thermo-mechanical models, developed using target geometries with shapes and sizes typical of manufactured ceramic products. In order to evaluate the goodness and the correctness of the developed models, some specimens having the the same shape of the target geometries used in FEM models have been tested at different load conditions and constraints.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/278166

Corrosion resistance of Zn-Ni-Al2O3 nanocomposite coatings
Porceedings of EUROCORR 2018 (European Federation of Corrosion Event No. 429)
Autore/i: Roventi, Gabriella; Giuliani, Giampaolo; Vicere', Annamaria; Bellezze, Tiziano
Editore: Polish Corrosion Society (PSK)
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Corrosion resistance of Zn-Ni-Al2O3 nanocomposite coatings was studied. Zn-Ni alloy was electrodeposited on mild steel substrate from an alkaline bath used by galvanic industry (Atotech). ZnNi-Al2O3 nanocomposite coatings were obtained by adding to the deposition bath 10 g L-1 of Al2O3 nanoparticles (delta-alumina, primary particle size: 13 nm). Electrodepositions were carried out at 25±1 °C under constant magnetic stirring and under galvanostatic control (current density: 10 and 30 mA cm-2). Homogeneous and compact coatings with low grain size have been obtained. All the electrodeposited alloys are constituted by cubic gamma-phase Ni5Zn21; the incorporation of Al2O3 nanoparticles does not change the orientation of gamma-phase. The Al2O3 content of the coatings was 1.1-1.6 wt%; the incorporation of allumina nanoparticles does not lead to a significant worsening in the morphology; only a slight increase in roughness was observed. Corrosion resistance of both Zn-Ni and Zn-Ni-Al2O3 coatings was studied by means of polarization resistance measurements and potentiodynamic polarizations performed at room temperature in 3.5 % NaCl solution. The obtained results indicate that, under the experimental conditions of this work, Al2O3 incorporation does not lead to a worsenig of corrosion resistance of ZnNi alloy because it does not significantly affect the coating morphology and structure.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/266148

Mechanical, electrical and self-sensing properties of cementitious mortars containing short carbon fibers
JOURNAL OF BUILDING ENGINEERING
Autore/i: Donnini, Jacopo; Bellezze, Tiziano; Corinaldesi, Valeria
Classificazione: 1 Contributo su Rivista
Abstract: This paper is aimed at exploring mechanical, electrical and self-sensing properties of cement-based mortars through the addition of short carbon fibers, at different dosages (2%, 3%, 4% by weight of cement). Compression and bending tests on carbon fiber reinforced mortars (CFRM) were performed. The addition of carbon fibers showed to enhance the mortars’ flexural strength by increasing the fibers content, while no improvement was found in the compressive strength. Electrical resistivity of the CFRM, at different days of curing, was evaluated by AC impedance measurements, using two stainless steel wire meshes as electrodes. The electrical resistivity decreased with time, until reaching a constant value after about 60 days of curing. Carbon fibers were able to drastically reduce the mortar resistivity, up to values below 150 Ω cm. The effect of fibers dosage on the ability of the mortar to change its electrical resistivity when subjected to different stress states was also studied. The specimens were gradually loaded up to 50–60% of the maximum compressive strength, carrying out two loading/unloading cycles, while resistivity was measured using a conductivity meter. Depending on the fibers dosage and stress state within the material, CFRM resistivity changed with significant variations.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/266205

Evaluating the Self-Sensing Ability of Cement Mortars Manufactured with Graphene Nanoplatelets, Virgin or Recycled Carbon Fibers through Piezoresistivity Tests
SUSTAINABILITY
Autore/i: Belli, Alberto; Mobili, Alessandra; Bellezze, Tiziano; Tittarelli, Francesca; Cachim, Paulo
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents the resistivity and piezoresistivity behavior of cement-based mortars manufacturedwithgraphenenanoplateletfiller(GNP),virgincarbonfibers(VCF)andrecycledcarbon fibers (RCF). GNP was added at 4% of the cement weight, whereas two percentages of carbon fibers werechosen,namely0.05%and0.2%ofthetotalvolume. Thecombinedeffectofbothfillerandfibers was also investigated. Mortars were studied in terms of their mechanical properties (under flexure and compression) and electrical resistivity. Mortars with the lowest electrical resistivity values were also subjected to cyclic uniaxial compression to evaluate the variations in electrical resistivity as a function of strain. The results obtained show that mortars have piezoresistive behavior only if they aresubjectedtoapriordryingprocess. Inaddition,dryspecimensexhibitahighpiezoresistivityonly when loaded with 0.2 vol.% of VCF and 0.4 wt.% of GNP plus 0.2 vol.% RCF, with a quite reversible relation between their fractional change in resistivity (FCR) and compressive strain.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/261671

Analysis of corrosion behaviour of aluminium alloy AA6012 samples processed by ECAP and cryogenic treatment [Analisi del comportamento a corrosione di campioni di alluminio AA6012 sottoposti a ECAP e trattamento criogenico]
LA METALLURGIA ITALIANA
Autore/i: Viceré, A.; Cabibbo, M.; Paoletti, C.; Roventi, G.; Bellezze, T.
Classificazione: 1 Contributo su Rivista
Abstract: Severe Plastic Deformations (SPD) have been used in order to obtain ultrafine-grained alloys improved in strength and wear resistance with an adequate ductility. Equal Channel Angular Pressing (ECAP) is one of these techniques that consists in pressing through a die, with two intersecting channels, equal in cross section, a sample that is forced to deform by shearing at the intersection of these channels. The sample retains the same cross-sectional area after pressing, so that it is possible to repeat the pressing several times. Modifications of the alloys microstructure produced by ECAP significantly influence their corrosion behaviour. In this work, the corrosion behaviour of the aluminium alloy AA6012 samples solutioned at 550°C/6h and then pressed through ECAP technique was investigated; some of these samples were submitted to a cryogenic treatment before being processed by ECAP. With more details, the samples examined in this work are as received extruded billets (TQ), solutioned at 550 °C/6h (TT), processed only one pass through ECAP (TT-ECAP 1) and submitted to cryo treatment before ECAP (TT-cryo ECAP 1). The samples TT-ECAP 1 were pressed into the ECAP die at room temperature until one pass. The cryogenic treated billets (TT-cryo ECAP 1) were dipped into liquid nitrogen for at least 1 minute immediately before being introduced into the ECAP die. During shear deformation, the cryotreated billets never reached room temperature. The evolution of microstructure was studied by means of optical microscope and TEM observations. The analysis of corrosion behaviour has been carried out at room temperature by means of electrochemical characterization in two different aqueous solutions at the same chloride concentrations (0.1M NaCl): a deareated solution at pH= 2 (solution 1) and an aerated solution at pH= 6.5 (solution 2). For this purpose, polarization resistance, potentiodynamic polarization and electrochemical impedance spectroscopy tests were performed. A three-electrode cell was used with a saturated calomel electrode (SCE, +0.241 V vs NHE) as a reference and two short-circuited platinum sheets as counter, all connected to a Gamry Reference 600 potentiostat. Polarization resistance measurements were carried out from Ecorr- 5 mV to Ecorr + 5 mV, Tafiel plot from Ecorr - 150 mV to Ecorr +150 mV and potentiodynamic polarizations, anodic and cathodic separated tests, from the corrosion potential (scan rate 0.166 mV/s). Electrochemical Impedance Spectroscopy (EIS) measurements were performed with an AC signal amplitude of 5 mV rms, 5 points/decade and a frequency range of 100 kHz- 10 mHz. Fig. 1 shows grain refinement of the AA6012 samples processed by ECAP (TT-ECAP 1 and TT-cryo ECAP 1) with respect to TT samples. Fig. 2 illustrates representative Tafel curves for each sample examined in deareated solution 1 (pH=2). All the samples showed active corrosion. TT and TT-cryo ECAP 1 samples present lower corrosion rate (icorr) than TQ and TT-ECAP 1 (symbols in Fig. 2). Polarization resistance results (Fig. 3) confirm the better corrosion behaviour of TT sample and the improvement in corrosion resistance of TT-cryo ECAP 1 samples with respect to TT-ECAP 1 ones in solution 1 (pH=2). Corrosion behavior in solution 2 (pH= 6.5) is mainly governed by oxygen diffusion and only limited differences are visible in Fig. 4 between the analyzed samples. Therefore, EIS measurements were carried out in order to obtain more information about the system under examination, which typically presented the impedance response shown in Fig. 5. Through the analysis of this response by the equivalent circuit of Fig. 6, the charge transfer resistance has been determined for all samples (Fig. 7). These results confirm the better corrosion behaviour of TT samples, the worsening of ECAPed samples and the improvement of the corrosion resistance given by cryogenic treatment before ECAP. In conclusion, solutioned samples (TT) show a better corrosion behaviour than as received (TQ) and ECAPed ones. Although severe plastic deformations worsen the corrosion behaviour of solutioned samples, cryogenic treatment before ECAP avoids the loss of the corrosion resistance of AA6012 alloy due to ECAP.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/258649

The role of cryogenic dipping prior to ECAP in the microstructure, secondary-phase precipitation, mechanical properties and corrosion resistance of AA6012 (Al-Mg-Si-Pb)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
Autore/i: Cabibbo, M.; Santecchia, E.; Mengucci, P.; Bellezze, T.; Vicere', Annamaria
Classificazione: 1 Contributo su Rivista
Abstract: Literature on ECAP generally deals with room temperature or high-temperature deformation regimes. Very few data on low-temperature SPD processes have been published. This study presents some experimental results on the effect of cryogenic treatment prior to ECAP-BC on microstructure modification, mechanical response, and corrosion behaviour of an AA6012 Al-Mg-Si-Pb alloy. This type of Pb-bearing AA6000-series alloy, is produced and used for its marked post-extrusion machinability. The mechanical properties were inferred by nanoindentation to measure hardness, H, and local elastic modulus, Er. These data were presented in form of maps to account for the whole H and Er evolution with cumulative strain. The experimental results showed significant microstructure differences between the cryogenic treated ECAP condition and the conventional ECAP at room temperature. These differences were also correlated with electron microscopy inspections, XRD. Finally, the cryogenic treatment prior ECAP also affected the alloy corrosion behaviour.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/253727

Binders alternative to Portland cement and waste management for sustainable construction – Part 2
JOURNAL OF APPLIED BIOMATERIALS & FUNCTIONAL MATERIALS
Autore/i: Coppola, Luigi; Bellezze, Tiziano; Belli, Alberto; C Bignozzi, Maria; Bolzoni, Fabio; Brenna, Andrea; Cabrini, Marina; Candamano, Sebastiano; Cappai, Marta; Caputo, Domenico; Carsana, Maddalena; Casnedi, Ludovica; Cioffi, Raffaele; Cocco6, Ombretta; Coffetti, Denny; Colangelo8, Francesco; Coppola, Bartolomeo; Corinaldesi, Valeria; Crea, Fortunato; Crotti, Elena; Daniele, Valeria; De Gisi, Sabino; Delogu, Francesco; V Diamanti, Maria; Di Maio, Luciano; Di Mundo, Rosa; Di Palma, Luca; Donnini, Jacopo; Farina, Ilenia; Ferone, Claudio; Frontera, Patrizia; Gastaldi, Matteo; Giosue', Chiara; Incarnato, Loredana; Liguori, Barbara; Lollini, Federica; Lorenzi, Sergio; Manzi, Stefania; Marino, Ottavio; Marroccoli, Milena; C Mascolo, Maria; Mavilia, Letterio; Mazzoli, Alida; Medici, Franco; Meloni, Paola; Merlonetti, Glauco; Mobili, Alessandra; Notarnicola, Michele; Ormellese, Marco; Pastore, Tommaso; Pia Pedeferri, Maria; Petrella, Andrea; Pia6, Giorgio; Redaelli, Elena; Roviello, Giuseppina; Scarfato, Paola; Scoccia, Giancarlo; Taglieri, Giuliana; Telesca, Antonio; Tittarelli, Francesca; Todaro, Francesco; Vilardi, Giorgio; Yang, Fan
Classificazione: 1 Contributo su Rivista
Abstract: The paper represents the “state of the art” on sustainability in construction materials. In Part 1 of the paper, issues related to production, microstructures, chemical nature, engineering properties, and durability of mixtures based on binders alternative to Portland cement were presented. This second part of the paper concerns the use of traditional and innovative Portland-free lime-based mortars in the conservation of cultural heritage, and the recycling and management of wastes to reduce consumption of natural resources in the production of construction materials. The latter is one of the main concerns in terms of sustainability since nowadays more than 75% of wastes are disposed of in landfills.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259227

Corrosion behaviour of bare and galvanized steel in geopolymer and Ordinary Portland Cement based mortars with the same strength class exposed to chlorides
CORROSION SCIENCE
Autore/i: Tittarelli, Francesca; Mobili, Alessandra; Giosuè, Chiara; Belli, Alberto; Bellezze, Tiziano
Classificazione: 1 Contributo su Rivista
Abstract: The corrosion behaviour of bare and galvanized steel reinforcements in geopolymeric and cementitious mortars, at three strength classes, has been investigated throughout the curing period and exposure to wet-dry cycles in 3.5% NaCl solution. During the curing, the high alkalinity of geopolymers prolongs the active state of both bare and galvanized steel. During the chloride exposure, fly ash geopolymers give the highest protection to reinforcements. The higher alkalinity of geopolymers compared to cement mortars seems to decrease the minimum free chloride threshold necessary to induce corrosion for galvanized steel, but it increases that for bare steel.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/255934

Study of stainless steels corrosion in a strong acid mixture. Part 2: anodic selective dissolution, weight loss and electrochemical impedance spectroscopy tests
CORROSION SCIENCE
Autore/i: Bellezze, Tiziano; Giuliani, Giampaolo; Viceré, Annamaria; Roventi, Gabriella
Classificazione: 1 Contributo su Rivista
Abstract: The corrosion resistance of austenitic stainless steels AISI 316L, AISI 904L and Sanicro 28 and duplex stainless steels SAF 2205, SAF 2507 and SAF 2707, was studied at 40 and 60 °C in a strong acid mixture containing tartaric acid saturated solution, H2SO4 and HCl. Anodic selective dissolution, weight loss and electrochemical impedance tests were performed. The results show that all stainless steels corrode actively and the micro-galvanic coupling, present on duplex stainless steels and 316L, determines severe selective corrosion and impairs their tendency to passivate. 904L and Sanicro 28 showed this tendency and the lowest corrosion rates.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/252859

Study of localized corrosion of AISI 430 and AISI 304 batches having different roughness
METALS
Autore/i: Bellezze, Tiziano; Viceré, Annamaria; Giuliani, Giampaolo; Sorrentino, Emanuele; Roventi, Gabriella
Classificazione: 1 Contributo su Rivista
Abstract: In this work, the localized corrosion resistance of different batches of AISI 430 and AISI 304 stainless steels, having Scotch-Brite surface finishing, was investigated as a function of their roughness (in terms of Rz) and chemical composition. The study was performed by recording anodic cyclic potentiodynamic polarization curves at room temperature in two NaCl solutions (0.35 and 1.75 wt %). From the anodic curves, corrosion potential (E-corr), protection potential (E-prot), and pitting potential (E-pit) were obtained. In general, the results indicate that AISI 304 has better localized corrosion resistance than AISI 430, both in terms of pitting initiation and repassivation ability, independently from roughness. In particular, an increase of roughness determined a decrease of E-pit only in the case of AISI 304 in the less concentrated NaCl solution. This result was related to the higher variability of the corresponding Rz values compared to those of AISI 430. Finally, from the analysis of the loop hysteresis of the anodic curves, in relation to E-pit - E-prot values, durability information on the tested stainless steels were obtained: AISI 304 shows higher corrosion performances with respect to AISI 430, thanks to the higher chromium content of the former compared to the latter.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/266075

Binders alternative to Portland cement and waste management for sustainable construction - Part 1
JOURNAL OF APPLIED BIOMATERIALS & FUNCTIONAL MATERIALS
Autore/i: Coppola, Luigi; Bellezze, Tiziano; Belli, Alberto; Chiara Bignozzi, Maria; Bolzoni, Fabio; Brenna, Andrea; Cabrini, Marina; Candamano, Sebastiano; Cappai, Marta; Caputo, Domenico; Carsana, Maddalena; Casnedi, Ludovica; Cioffi, Raffaele; Cocco, Ombretta; Coffetti, Denny; Colangelo, Francesco; Coppola, Bartolomeo; Corinaldesi, Valeria; Crea, Fortunato; Crotti, Elena; Daniele, Valeria; De Gisi, Sabino; Delogu, Francesco; Vittoria Diamanti, Maria; Di Maio, Luciano; Di Mundo, Rosa; Di Palma, Luca; Donnini, Jacopo; Farina, Ilenia; Ferone, Claudio; Frontera, Patrizia; Gastaldi, Matteo; Giosue', Chiara; Incarnato, Loredana; Liguori, Barbara; Lollini, Federica; Lorenzi, Sergio; Manzi, Stefania; Marino, Ottavio; Marroccoli, Milena; Cristina Mascolo, Maria; Mavilia, Letterio; Mazzoli, Alida; Medici, Franco; Meloni, Paola; Merlonetti, Glauco; Mobili, Alessandra; Notarnicola, Michele; Ormellese, Marco; Pastore, Tommaso; Pia Pedeferri, Maria; Petrella, Andrea; Pia, Giorgio; Redaelli, Elena; Roviello, Giuseppina; Scarfato, Paola; Scoccia, Giancarlo; Taglieri, Giuliana; Telesca, Antonio; Tittarelli, Francesca; Todaro, Francesco; Vilardi and Fan Yang, Giorgio
Classificazione: 1 Contributo su Rivista
Abstract: This review presents “a state of the art” report on sustainability in construction materials. The authors propose different solutions to make the concrete industry more environmentally friendly in order to reduce greenhouse gases emissions and consumption of non-renewable resources. Part 1—the present paper—focuses on the use of binders alternative to Portland cement, including sulfoaluminate cements, alkali-activated materials, and geopolymers. Part 2 will be dedicated to traditional Portland-free binders and waste management and recycling in mortar and concrete production.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259226

Effect of the Type of Surface Treatment and Cement on the Chloride Induced Corrosion of Galvanized Reinforcements
IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING
Autore/i: Tittarelli, Francesca; Mobili, Alessandra; Vicere', Annamaria; Roventi, Gabriella; Bellezze, Tiziano
Classificazione: 1 Contributo su Rivista
Abstract: The effect of a new passivation treatment, obtained by immersion of the galvanized reinforcements in a trivalent chromium salts based solution, on the chlorides induced corrosion has been investigated. To investigate also the effect of cement alkalinity on corrosion behaviour of reinforcements, concretes manufactured with three different European cements were compared. The obtained results show that the alternative treatment based on hexavalent chromium-free baths forms effective protection layers on the galvanized rebar surfaces. The higher corrosion rates of zinc coating in concrete manufactured with Portland cement compared to those recorded for bars in concrete manufactured with pozzolanic cement depends strongly on the higher chloride content at the steel concrete interface.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251669

Electrodeposition of Zn-Ni-ZrO2, Zn-Ni-Al2O3 and Zn-Ni-SiC nanocomposite coatings from an alkaline bath
INTERNATIONAL JOURNAL OF ELECTROCHEMICAL SCIENCE
Autore/i: Roventi, Gabriella; Giuliani, Giampaolo; Pisani, Michela; Bellezze, Tiziano
Classificazione: 1 Contributo su Rivista
Abstract: Zn-Ni-ZrO2, Zn-Ni-Al2O3 and Zn-Ni-SiC nanocomposite coatings were obtained on mild steel substrate by electrodeposition technique from an alkaline bath. ZrO2, Al2O3 and SiC nanoparticles were added to the bath with concentrations of 5 and 10 g dm-3. The effect of current density and particles concentration on the deposit composition, morphology, structure and microharness was studied. The results show that the addition of nanoparticles to the plating solution does not affect significantly Zn-Ni electrodeposition process and alloy Ni percentage. X-ray diffraction patterns of the coatings show only the presence of cubic γ-phase Ni5Zn21. With ZrO2 or Al2O3 nanoparticles, homogeneous and compact deposits with low grain size were obtained. On the contrary, SiC nanoparticles incorporation perturbs the growth of the alloy matrix by reducing γ-phase orientation. ZrO2 and Al2O3 lead to an increase in the coating microhardness, whereas SiC leads to a decrease, due to the strong modification induced in the alloy structure.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/245745

Solutions for critical raw materials under extreme conditions: A review
MATERIALS
Autore/i: Grilli, Maria Luisa; Bellezze, Tiziano; Gamsjäger, Ernst; Rinaldi, Antonio; Novak, Pavel; Balos, Sebastian; Piticescu, Radu Robert; Ruello, Maria Letizia
Classificazione: 1 Contributo su Rivista
Abstract: In Europe, many technologies with high socio-economic benefits face materials requirements that are often affected by demand-supply disruption. This paper offers an overview of critical raw materials in high value alloys and metal-matrix composites used in critical applications, such as energy, transportation and machinery manufacturing associated with extreme working conditions in terms of temperature, loading, friction, wear and corrosion. The goal is to provide perspectives about the reduction and/or substitution of selected critical raw materials: Co, W, Cr, Nb and Mg.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/249739

Studio della protezione catodica di un sistema che simula gli interstizi su condotte sottomarine (Study of the cathodic protection applied on a system simulating occluded cells on sealines)
LA METALLURGIA ITALIANA
Autore/i: Bellezze, T.; Roventi, G.; Fratesi, R.; Rosmarini, S.
Classificazione: 1 Contributo su Rivista
Abstract: In this work, a study on the effect of the cathodic protection in a system simulating a crevice that, in real cases, is present in some types of connections used for submarine pipelines was carries out. The crevice was simulated in laboratory by overlapping two rectangular plates of the same size: one of them has been obtained with an ordered series of metal elements of low-alloy carbon steel, embedded in an epoxy resin; the other was a plate of PVC. All metal elements were connected to the same galvanic anode of an aluminium alloy, placed in front of the crevice opening. The system was immersed in a tank filled with artificial seawater. Although with different times, by varying the thickness of the crevice (2, 4 and 10 mm), all metal elements have achieved the conditions of immunity and the current lines reached them, even at the crevice bottom. At the end of the experimental work, a finite element simulation of the studied system was developed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/252856

Analisi della resistenza a corrosione localizzata di differenti partite di acciai inossidabili AISI 304 e AISI 430
Giornate Nazionali sulla CORROSIONE e PROTEZIONE
Autore/i: Bellezze, Tiziano; Vicere', Annamaria; Giuliani, Giampaolo; Sorrentino, E.; Roventi, Gabriella
Editore: Associazione Italiana di Metallurgia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In questo lavoro è stato studiato il comportamento a corrosione localizzata di differenti partite di acciai inossidabili AISI 430 e AISI 304, con finitura superficiale Scotch Brite. L’indagine è stata eseguita a temperatura ambiente mediante una caratterizzazione elettrochimica in soluzioni acquose a diversa concentrazione di cloruri (NaCl 1,75% e 0,35% in peso). A questo scopo, sono state registrate numerose curve di polarizzazione anodica ciclica; i risultati sono stati messi in relazione con la composizione e la rugosità superficiale degli acciai studiati. Dai risultati sperimentali è emerso che l’AISI 304 mostra una maggiore resistenza a corrosione localizzata rispetto all’AISI 430, nonostante la sua maggiore rugosità superficiale. Infine, è stato osservato che quest’ultima caratteristica peculiare dei campioni studiati gioca un ruolo modesto nell’ambito dello stesso tipo di acciaio; eventualmente, tale ruolo risulta rilevabile solo quando la rugosità presenta una significativa variabilità.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/249746

DEGRADATION ASSESSMENT OF POLYMERS FOR BIOMEDICAL APPLICATIONS UNDER STERILIZATION CONDITIONS
Baltic Polymer Symposium 2017
Autore/i: Tittarelli, Francesca; Conti, Carla; Favoni, Orlando; Bellezze, Tiziano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251231

The Effect of Fly Ash on the Corrosion Behaviour of Galvanised Steel Rebars in Concrete
IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING
Autore/i: Tittarelli, Francesca; Mobili, Alessandra; Bellezze, Tiziano
Classificazione: 1 Contributo su Rivista
Abstract: The effect of fly ash on the corrosion behaviour of galvanised steel rebars in cracked concrete specimens exposed to wet-dry cycles in a chloride solution has been investigated. The obtained results show that the use of fly ash, replacing either cement or aggregate, always improves the corrosion behaviour of galvanised steel reinforcements. In particular, the addition of fly ash, even in the presence of concrete cracks, decreases the corrosion rate monitored in very porous concretes, as those with w/c = 0.80, to values comparable with those obtained in good quality concretes, as those with w/c = 0.45. Therefore, fly ash cancels the negative effect, at least from the corrosion point of view, of a great porosity of the cement matrix.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251356

Influence of aeration cycles on mechanical characteristics of elastomeric diffusers in biological intermittent processes: Accelerated tests in real environment
WATER RESEARCH
Autore/i: Eusebi, ANNA LAURA; Bellezze, Tiziano; Chiappini, Gianluca; Sasso, Marco; Battistoni, Paolo
Classificazione: 1 Contributo su Rivista
Abstract: The paper deals with the evaluation of the effect of on/off switching of diffuser membranes, in the intermittent aeration process of the urban wastewater treatments. Accelerated tests were done using two types of commercial EPDM diffusers, which were submitted to several consecutive cycles up to the simulation of more than 8 years of real working conditions. The effect of this switching on the mechanical characteristics of the membranes was evaluated in terms of pressure increment of the air operating at different flow rates (2, 3.5 and 6 m3/h/diff): during accelerated tests, such increment ranged from 2% to 18%. The intermittent phases emphasized the loss both of the original mechanical proprieties of the diffusers and of the initial pore shapes. The main cause of pressure increment was attributed to the fouling of the internal channels of the pores. Further analyses performed by scanning electron microscopy and by mechanical tests on EPDM membrane, using a traditional tensile test and a non destructive optical method, from which the Young's Modulus was obtained, supported previous conclusions. Any changes in terms of oxygen transfer parameters (KLa and SOTE%) were specifically founded by causing to the repeated on/off switching.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/247022

Comportamento a corrosione di armature in acciaio e acciaio zincato in matrici geo-polimeriche e cementizie esposte a cloruri e carbonatazione accelerata
Atti delle Giornate di Studio sui Geopolimeri IX edizione Geopolimeri e Compositi
Autore/i: Mobili, Alessandra; Belli, Alberto; Giosue', Chiara; Bellezze, Tiziano; Tittarelli, Francesca
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Il presente lavoro confronta il comportamento a corrosione di armature in acciaio e acciaio zincato in matrici cementizie e geopolimeriche a pari classe di resistenza (R1, R2, R3). I risultati hanno mostrato che l’elevata alcalinità dei geopolimeri rallenta il raggiungimento della condizione di passività delle armature, in particolare per quelle in acciaio zincato. Dopo circa 10 giorni, tutte le armature danno velocità di corrosione paragonabili a quelle delle barre immerse nelle malte cementizie. La bassa porosità dei geopolimeri con cenere volante limita l’ingresso dei cloruri e offre la maggiore protezione a entrambi i tipi di barre. Durante l’esposizione ai cicli di bagnasciuga in acqua, successiva all’esposizione in camera di carbonatazione, entrambi i tipi di armatura registrano le più basse velocità di corrosione se immersi nei geopolimeri con cenere volante.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/245133

Comportamento a corrosione di armature zincate in malte geopolimeriche e cementizie a parità di classe di resistenza - Corrosion behavior of galvanized steel reinforcements in geopolymeric and cementitious mortars at the same strength class
LA METALLURGIA ITALIANA
Autore/i: Mobili, Alessandra; Belli, Alberto; Giosue', Chiara; Bellezze, Tiziano; Tittarelli, Francesca
Classificazione: 1 Contributo su Rivista
Abstract: The corrosion behavior of galvanized steel rebars embedded in geopolymer mortar was compared to that of the same reinforcements embedded in a cementitious mortar with the same mechanical strength class. The corrosion potential and the corrosion rate of these bars were measured throughout the first month of curing for all manufactured specimens, and then one half was submitted to weekly wet-dry cycles in 3.5% NaCl solution and the other half to weekly wet-dry cycles in tap water after exposure to a chamber with 3% of CO2. In the first month, the high alkalinity of geopolymers delayed the achievement of the galvanized steel passive state, but after reinforcements reached the same corrosion rates of those embedded in the cementitious mortars. In chlorides exposure, the lowest porosity of geopolymers hindered the ingress of chloride ions offering the highest protection to reinforcements. Also in carbonated matrices, during exposure to wet-dry cycles in tap water, galvanized bars had the lowest corrosion rates when embedded in the geopolymeric matrices.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/250491

Bond behavior of FRCM carbon yarns embedded in a cementitious matrix: Experimental and numerical results
Mechanics of Masonry Structures Strengthened with Composite Materials II
Autore/i: Donnini, Jacopo; Lancioni, Giovanni; Bellezze, Tiziano; Corinaldesi, Valeria
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/252864

Effect of commercial and waste carbonaceous fillers on the mechanical and electrical properties of innovative mortars
JOURNAL OF APPLIED BIOMATERIALS & FUNCTIONAL MATERIALS
Autore/i: Mobili, Alessandra; Belli, Alberto; Giosue', Chiara; Mancini, Roberto; Mazzoli, Alida; Bellezze, Tiziano; Tittarelli, Francesca
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251377

Comportamento a corrosione di armature zincate in malte geopolimeriche e cementizie a parità di classe di resistenza - Corrosion behavior of galvanized steel reinforcements in geopolymeric and cementitious mortars at the same strength class
Giornate Nazionali sulla Corrosione e Protezione
Autore/i: Mobili, Alessandra; Belli, Alberto; Giosue', Chiara; Bellezze, Tiziano; Tittarelli, Francesca
Editore: Associazione Italiana di Metallurgia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The corrosion behavior of galvanized steel rebars embedded in geopolymer mortar was compared to that of the same reinforcements embedded in a cementitious mortar with the same mechanical strength class. The corrosion potential and the corrosion rate of these bars were measured throughout the first month of curing for all manufactured specimens, and then one half was submitted to weekly wet-dry cycles in 3.5% NaCl solution and the other half to weekly wet-dry cycles in tap water after exposure to a chamber with 3% of CO2. In the first month, the high alkalinity of geopolymers delayed the achievement of the galvanized steel passive state, but after reinforcements reached the same corrosion rates of those embedded in the cementitious mortars. In chlorides exposure, the lowest porosity of geopolymers hindered the ingress of chloride ions offering the highest protection to reinforcements. Also in carbonated matrices, during exposure to wet-dry cycles in tap water, galvanized bars had the lowest corrosion rates when embedded in the geopolymeric matrices.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/249647

The use of a Phosphate-Based Migrating Corrosion Inhibitor to Repair Reinforced Concrete Elements Contaminated by Chlorides
IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING
Autore/i: Tittarelli, Francesca; Mobili, Alessandra; Bellezze, Tiziano
Classificazione: 1 Contributo su Rivista
Abstract: The use of sodium monofluorophosphate (MFP) was experimented as migrator inhibiting treatment against corrosion of reinforced concrete elements induced by chlorides. The results show that sodium monofluorophosphate, applied by surface impregnation, is able to slow down reinforcement corrosion only for reinforcing steel bars with concrete cover not thicker than 1 cm. This limitation is most probably due to the difficulty, with the type of application adopted, in making MFP to reach concentrations high enough to inhibit the corrosive process at greater depths from the impregnation surface.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251355

Galvanic corrosion of the seam weld in Zn–Al coated steel pipes manufactured by electric resistance welding
MATERIALS AND CORROSION
Autore/i: Andreatta, F; Bellezze, Tiziano; Lanzutti, A.; Roventi, Gabriella; Fedrizzi, L.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/249738

Corrosion behaviour of austenitic and duplex stainless steels in an industrial strongly acidic solution
MATERIALS AND CORROSION
Autore/i: Bellezze, Tiziano; Giuliani, Giampaolo; Roventi, Gabriella; Fratesi, Romeo; Andreatta, F.; Fedrizzi, L.
Classificazione: 1 Contributo su Rivista
Abstract: AISI 316L metallic components of an industrial plant, producing tartaric acid as by-product of grape pressing, were subjected to a so severe corrosive attack to promote the search of alternative stainless steels for this specific application. The aggressive industrial solution is strongly acidic and it contains large amounts of chlorides and sulphates and it operates in the temperature range of 25–60 °C. As possible alternative materials to AISI 316L, two super austenitic stainless steels, AISI 904L and SanicroTM 28, and three duplex stainless steels, SAF 2707 HDTM, SAF 2507TM and SAF 2205TM, were tested. The steels were characterised by means of chemical analysis, metallographic observations and anodic polarisations in a tartaric acid saturated solution, both in presence and in absence of chlorides and sulphates. The AISI 316L alloy showed the presence of ferrite δ at the austenitic grain boundaries, which is responsible for a selective attack and severe damage of this material. Among the tested steels, as alternative to AISI 316L, Sanicro 28TM and AISI 904L can be considered promising, with a preference for Sanicro 28TM. SAF 2707 HDTM showed a passive behaviour only with a mirror surface finishing, which is not acceptable for service conditions.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/233582

Effect of Cr VI on the passivation of galvanized steel in concrete
The annual event of the European Federation of Corrosion EUROCORR 2016 Advances in linking science to engineering
Autore/i: Bellezze, Tiziano; Roventi, Gabriella; Fratesi, Romeo; Timofeeva, Daria
Editore: European Federation of Corrosion
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The effect of Cr VI present in the cement on the active corrosion of galvanized steel was studied. The investigation was performed by means of corrosion potential measurements performed both in concrete and in Ca(OH)2 saturated solution. The obtained results indicate that Cr VI promotes the passivation of galvanized steel due to its inhibitory effect on the zinc corrosion. The higher the concentration of Cr VI, the shorter the time required for the passivation of zinc. When the concentration of Cr VI reaches 15 ppm (referred to the weight of the cement), the passivation occurs immediately after immersion. This acceleration avoids the hydrogen evolution, which causes the rebars adhesion loss during the early age period in contact with concrete, when the cement paste is not yet hardened. A reactivation process, followed by a new passivation, was observed for concentrations of Cr VI ≥ 6 ppm; this behavior does not occur in Ca(OH)2 saturated solution. The reactivation process is attributed to the depletion of Cr VI on the galvanized steel surface, caused probably by the aging of concrete, which consumes the pore solution. The second passivation is stable and is due to the formation of calcium hydroxyzincate.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/249367

COMMERCIAL AND WASTE CARBON BASED NANO/MICRO FILLERS FOR THE DEVELOPMENT OF INNOVATIVE AND MULTIFUNCTIONAL MORTARS
Cost Action 15107, Multi-Functional Nano-Carbon Composite Materials - MULTICOMP, Scientific Kick-Off meeting
Autore/i: Tittarelli, Francesca; Belli, Alberto; Mobili, Alessandra; Roventi, Gabriella; Corinaldesi, Valeria; Mazzoli, Alida; Bellezze, Tiziano; Ruello, Maria Letizia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/246367

COMMERCIAL AND WASTE CARBON BASED NANO/MICRO FILLERS FOR THE DEVELOPMENT OF INNOVATIVE AND MULTIFUNCTIONAL MORTARS
National Young Researchers' Forum on Materials Science and Technology
Autore/i: Belli, Alberto; Mobili, Alessandra; Giosue', Chiara; Toscano, Giuseppe; Mazzoli, Alida; Bellezze, Tiziano; Tittarelli, Francesca
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/246366

Effect of beta and gamma ray sterilization on the properties of polymeric materials for biomedical applications
JOURNAL OF APPLIED BIOMATERIALS & FUNCTIONAL MATERIALS
Autore/i: Tittarelli, Francesca; Conti, Carla; Favoni, Orlando; Mazzoli, Alida; Bellezze, Tiziano
Classificazione: 1 Contributo su Rivista
Abstract: The goal of this study is to evaluate the effect of sterilization by gamma and beta radiation on the properties of four different polymeric specimens for biomedical use: a PVC pipe for connection in dialysis and heart surgery devices; a PVC band for enteral and parenteral nutrition bags, a TRIFLEX pipe (internal PE, middle PE/PVC, external PVC) for connection, a PC rigid pipe for the connection of tubes and bags for infusions. The effect of sterilization was studied by means of tensile mechanical characterization, thermo-gravimetric and morphological analysis and FT-IR spectroscopy. UV-VIS spectroscopy was used to evaluate the yellowing index, determined by radiation exposure. For each specimen, a no-sterilized one was tested for comparison.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/238300

THE EFFECT OF FLY ASH ON THE CORROSION BEHAVIOUR OF GALVANISED STEEL REBARS IN CONCRETE
International Conference on Advanced Material Technologies (ICAMT)-2016. Issue - I. Elsevier Materials Today: Proceedings
Autore/i: Tittarelli, Francesca; Mobili, Alessandra; Bellezze, Tiziano
Editore: materialstoday:proceedings; Diet; PGC;CSTPLI
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The effect of fly ash on the corrosion behaviour of galvanised steel rebars in cracked concrete specimens exposed to wet-dry cycles in a chloride solution has been investigated. The obtained results show that the use of fly ash, replacing either cement or aggregate, always improves the corrosion behaviour of galvanised steel reinforcements. In particular, the addition of fly ash, even in the presence of concrete cracks, decreases the corrosion rate monitored in very porous concretes, as those with w/c = 0.80, to values comparable with those obtained in good quality concretes, as those with w/c = 0.45. Therefore, fly ash cancels the negative effect, at least from the corrosion point of view, of a great porosity of the cement matrix.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/249675

STUDY ON THE EFFICIENCY OF A COMBINED CATHODIC PROTECTION SYSTEM: MAGNESIUM SACRIFICIAL ANODE AND TITANIUM IMPRESSED CURRENT ANODE INSIDE DOMESTIC BOILER
The annual event of the European Federation of Corrosion EUROCORR 2016 Advances in linking science to engineering
Autore/i: Mingo, Antonio; Bellezze, Tiziano; Roventi, Gabriella; Mancini, A.; Fratesi, Romeo
Editore: European Federation of Corrosion
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this work, the efficiency of a combined cathodic protection system composed by a sacrificial anode of magnesium and an impressed current anode of titanium, both installed inside a domestic boiler of 60L, was studied. The system was studied varying the specific conductivity of the water (50 µS/cm - 1000 µS/cm) and the temperature (20°C - 75°C). For assessing the cathodic protection efficiency, six localized probes were developed and located on the critical points of the boiler tank such as welded joints. These probes were able to verify the efficiency of the cathodic protection system through localized measurement of potentials of simulated defects placed on the internal walls of the tank. A monitoring workstation was set up to measure continuously the potentials in correspondence of the six probes, the heating element flange and the tank walls. The study showed that the protection system was able to protect all the metallic parts of the boiler in each experimental conditions. Furthermore, even an overprotection condition of the system, determining a possible hydrogen evolution was observed. In order to eliminate this issue and to guarantee a good management of the combined cathodic protection system, it could be helpful to decrease the current supplied by the impressed current anode.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/249292

Cathodic protection modelling of a propeller shaft
CORROSION SCIENCE
Autore/i: Lorenzi, Sergio; Pastore, Tommaso; Bellezze, Tiziano; Fratesi, Romeo
Classificazione: 1 Contributo su Rivista
Abstract: Current and potential distributions on a stainless steel propeller shaft protected by galvanic anodes were investigated by means of Finite Element Method (FEM) modelling. The effect of seawater flow and shaft rotation was evaluated. The results of simulations are compared with experimental measurements performed on steady shaft in natural seawater. Modest polarization can be noticed in all operating conditions, not sufficient for preventing biofilm action on localized corrosion initiation. Only in stagnant conditions, without any water renewal, the consumption of oxygen leads to an appreciable potential decreasing to match the limits of normal protection indicated in the European standards.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/245746

Metakaolin and fly ash alkali-activated mortars compared with cementitious mortars at the same strength class
CEMENT AND CONCRETE RESEARCH
Autore/i: Mobili, Alessandra; Belli, Alberto; Giosue', Chiara; Bellezze, Tiziano; Tittarelli, Francesca
Classificazione: 1 Contributo su Rivista
Abstract: Alkali activated and cementitious mortars belonging to R1 ≥ 10 MPa, R2 ≥ 15 MPa and R3 ≥ 25 MPa strength classes are tested and compared in terms of workability, dynamic modulus of elasticity, porosimetry and water vapour permeability. Capillary water absorption, drying shrinkage, resistance to sulphate attack and corrosion behaviour of embedded bare and galvanized reinforcements have also been investigated. In alkali activated mortars, drying shrinkage is higher than that of cementitious mortars but restrained shrinkage is lower due to lower modulus of elasticity. Water vapour permeability is more pronounced in alkali activated mortars, and capillary water absorption is lower in those prepared with fly ash. The high alkalinity of alkali activated mortars was seen to delay the onset of the passive state in particular for galvanized reinforcements, but after one month of curing they were found to reach the same corrosion rates of those embedded in cementitious mortars.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/238869

Electrodeposition of nickel-zinc alloy coatings with high nickel content
SURFACE & COATINGS TECHNOLOGY
Autore/i: Roventi, Gabriella; Cecchini, Raimondo; Fabrizi, Alberto; Bellezze, Tiziano
Classificazione: 1 Contributo su Rivista
Abstract: The electrodeposition of Ni–Zn alloy coatings with high nickel content from a Watts type bath was studied. The investigation was performed by means of cyclic voltammetry, potentiostatic electrodeposition, X-ray diffraction, energy dispersive X-ray analysis, scanning electron microscopy and transmission electron microscopy. The effect of the experimental parameters (deposition potential, bath temperature, zinc concentration, presence of additives) on the coating composition, morphology and structure was studied. The obtained results show that the addition of Zn2+ to the deposition bath leads to a strong decrease in the cathodic current density indicating a remarkable inhibition of Ni reduction. Even if anomalous codeposition was observed for all the studied experimental conditions, nickel rich alloys were obtained due to the mass transport control of zinc deposition. A strong decrease in the current efficiencies was observed when Zn percentage in the deposit was higher than 7wt.%. The incorporation of Zn in the fcc Ni lattice leads to a remarkable decrease in the grain size. The presence of nanocrystalline Ni–Zn beta-phase was observed in the alloys having Zn content higher than about 8 wt.%.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/227917

Metakaolin and fly ash based geopolymers compared with cementitious mortars of the same strength class: performances and corrosion behaviour of black and galvanized steel bars
Geopolymers: the route to eliminate waste and emissions in ceramic and cement manufacturing
Autore/i: Mobili, Alessandra; Giosue', Chiara; Belli, Alberto; Bellezze, Tiziano; Tittarelli, Francesca
Editore: ECI Engineering Conference International
Luogo di pubblicazione: New York
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/227812

Comportamento a corrosione di acciai inossidabili in una soluzione satura di acido tartarico
Atti delle Giornate Nazionali sulla Corrosione e Protezione XI Edizione - Ferrara 15-17 giugno 2015
Autore/i: Bellezze, Tiziano; Roventi, Gabriella; Fratesi, Romeo; Andreatta, F.; Fedrizzi, L.
Editore: Associazione Italiana di Metallurgia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: I componenti metallici in AISI 316L di un impianto industriale, che produce acido tartarico come sottoprodotto della spremitura dell’uva, hanno subito un severo attacco corrosivo tanto da promuovere la ricerca di acciai alternativi. La soluzione aggressiva industriale è fortemente acida, contiene cloruri e solfati, sotto forma dei rispettivi acidi, e opera nell’intervallo di temperatura di 25-60 °C. In questo lavoro, come materiali alternativi, sono stati considerati due acciai super-austenitici, AISI 904L e Sanicro 28, e tre acciai duplex, SAF 2707, SAF 2507 e SAF 2205. Le leghe sono state caratterizzate con l’analisi chimica, metallografica e mediante le curve di polarizzazione anodica nella soluzione satura di acido tartarico, sia in assenza che in presenza di cloruri e solfati. Dai risultati ottenuti, è emerso che l’AISI 316L utilizzato presenta la ferrite delta al bordo dei grani che è responsabile di un attacco selettivo che conduce al forte danneggiamento di questo materiale. Degli altri acciai testati, sono risultati promettenti come alternativa all’AISI 316L, il Sanicro 28 e l’AISI 904L. In un primo momento, era sembrato piuttosto interessante il SAF 2707, a comportamento passivo indipendentemente dalle condizioni di prova. Successivamente, si è visto che esso mantiene questo comportamento solo con una finitura metallica “a specchio”, che magari è poco corrispondente alle reali condizioni di impiego del materiale.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/227499

Geopolymeric and cementitious mortars with the same mechanical strength class: performances and corrosion behaviour of black and galvanized steel bars
Durability and Sustainability of Concrete Structures ACI SP-305
Autore/i: Mobili, Alessandra; Giosue', Chiara; Belli, Alberto; Bellezze, Tiziano; Tittarelli, Francesca
Editore: American Concrete Institute
Luogo di pubblicazione: Farmington Hill, Michigan 48331
Classificazione: 2 Contributo in Volume
Abstract: In the prospect of reducing CO2 emissions and landfilling of waste materials, the preparation of sustainable mortars by alkali activation was studied. According to EN 1504-3:2005, geopolymeric and cementitious mortars belonging to different strength classes (R1 ≥ 10 MPa, R2 ≥ 15 MPa and R3 ≥ 25 MPa) were tested and compared. Geopolymers were obtained with fly ash or metakaolin and a blend of sodium silicate and NaOH (or KOH). Mortars were tested in terms of workability, dynamic modulus of elasticity, drying and restrained shrinkage and porosimetry. Durability was also investigated in terms of water vapour permeability, capillary water absorption and corrosion of possible embedded rebars during the curing period and wet-dry cycles in 3.5% NaCl solution. Results showed that geopolymers are subjected to higher drying shrinkage but lower restrained shrinkage than cementitious mortars. Water vapour permeability was higher in geopolymers and capillary water absorption was lower especially in fly ash geopolymers than those of cementitious mortars. During the first month, the high alkalinity of geopolymers extends the active state of both black and galvanized steel bars. However, when exposed to chlorides, fly ash geopolymers offer a higher protection to reinforcements than cementitious mortars.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/228051

Caratterizzazione elettrochimica localizzata di tubi in acciaio zincato saldati mediante tecnologia ERW
Atti delle Giornate Nazionali sulla Corrosione e Protezione XI Edizione - Ferrara 15-17 giugno 2015
Autore/i: Andreatta, F.; Fedrizzi, L.; Bellezze, Tiziano; Fratesi, Romeo
Editore: Associazione Italiana di Metallurgia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: L’oggetto di questo studio è un tubo di acciaio con rivestimento in lega Zn-Al (0,8%) ottenuto per saldatura di lamiera prezincata con tecnologia ERW (electric resistance welding). Il comportamento elettrochimico del tubo zincato in acqua di rete è stato studiato con un approccio di tipo localizzato mediante microcella al fine di valutare l’accoppiamento galvanico tra l’acciaio e lo strato di zincatura. In particolare, tale aspetto è stato valutato nella zona della saldatura dove lo strato di zincatura può essere localmente danneggiato o rimosso dal processo di saldatura. Inizialmente è stato caratterizzato uno spezzone di tubo nuovo. Successivamente, è stato caratterizzato uno spezzone di tubo esercito in condizioni tali da promuovere il fenomeno della inversione di coppia galvanica Zn-Fe. Le curve di polarizzazione acquisite sulla sezione di tubo nuovo hanno evidenziato che il cordone di saldatura presenta comportamento anodico rispetto al metallo base. Inoltre, le curve ottenute sulla superficie interna del tubo nuovo indicano che lo strato di zincatura è in grado di proteggere catodicamente la regione della saldatura in cui lo strato di zincatura è stato localmente rimosso durante saldatura. Le curve acquisite sul tubo esercito mostrano chiaramente il fenomeno della inversione della coppia galvanica con marcata corrosione localizzata longitudinalmente lungo la saldatura.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/227500

Effect of beta and gamma ray sterilization on the properties of polymeric materials for biomedical applications
X Convegno INSTM 2015 Book of Abstracts
Autore/i: Tittarelli, Francesca; Conti, Carla; Favoni, Orlando; Mazzoli, Alida; Bellezze, Tiziano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The goal of this study is to evaluate the effect of sterilization by beta and gamma radiation on the properties of four different polymeric specimens for biomedical use (Figure 1): a PVC pipe for connection in dialysis and heart surgery devices; a PVC band for enteral and parenteral nutrition bags, a TRIFLEX pipe (internal PE, middle PE/PVC, external PVC) for connection, a PC rigid pipe for the connection of tubes and bags for infusions. The effect of sterilization was studied by means of tensile mechanical characterization, thermo-gravimetric and morphological analysis and FT-IR spectroscopy. UV-VIS spectroscopy was used to evaluate the yellowing index, determined by radiation exposure. For each specimen, a no-sterilized one was tested for comparison.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/227441

Zn-ZrO2 nanocomposite coatings obtained by electrodeposition
Book of abstract - X Convegno Nazionale sulla Scienza e Tecnologia dei Materiali - Favignana (TP) 28 giugno -1 luglio 2015
Autore/i: Roventi, Gabriella; Bellezze, Tiziano; Fratesi, Romeo
Editore: Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali
Luogo di pubblicazione: Firenze
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In the present work Zn-ZrO2 nanocomposite coatings (ZrO2 0.2-2.5 wt%) on mild steel substrate have been produced by electrodeposition technique with high current efficiency. Electrodepositions were performed at 35°C by using a chloride bath containing gelatine and yttria-stabilized zirconia nanoparticles (<100 nm); the tests were carried out under galvanostatic control with pulsed direct current, using a cathodic square wave (pulse frequency 1 Hz, duty cycle 50%). The coatings were characterized by means of X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and Vickers microhardness measurement. Corrosion potential and polarization resistance measurements were performed in 3.5 % NaCl solution. The composite coatings showed an improvement in hardness and in corrosion resistance with respect to the pure zinc coatings.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/227502

Metakaolin and fly ash based geopolymers compared with cementitious mortars of the same strength class: performances and corrosion behaviour of black and galvanized steel bars
Geopolymers: The route to eliminate waste and emissions in ceramic and cement manufacturing
Autore/i: Mobili, Alessandra; Giosue', Chiara; Belli, Alberto; Bellezze, Tiziano; Tittarelli, Francesca
Editore: Società Ceramica Italiana
Luogo di pubblicazione: Bologna
Classificazione: 2 Contributo in Volume
Abstract: Mechanical, morphological and durability aspects of three types of geopolymer mortars were compared with those of traditional cementitious mortars of comparable compressive strength. To this aim, mortars belonging to three mechanical strength classes (R1 ≥ 10 MPa, R2 ≥ 15 MPa and R3 ≥ 25 MPa according to EN 1504-3:2005) were tested and compared. Geopolymers were obtained with fly ash and metakaolin as precursors and a mixture of sodium silicate and NaOH or KOH as liquid activators. In order to obtain R1, R2 and R3 mortars cementitious mixtures were prepared by partial substitution of Portland cement with hydraulic lime, while geopolymers were prepared by varying the concentration of NaOH or KOH with a waterglass/hydroxide ratio always equal to 1. The obtained samples were characterized both in the fresh and in the hardened state. The first was evaluated by workability and density of the fresh mortar, the latter by compressive strength, dynamic modulus of elasticity, adhesive strength on ceramic surface, free and restrained shrinkage and by microstructural analysis such as SEM and mercury porosimetry. Durability aspects were also investigated through water vapor permeability, capillary water absorption, resistance to salt crystallization and corrosion of possible embedded rebars. Corrosion tests were carried out by measuring corrosion potential and corrosion rates of black and galvanized steel bars during both the curing period and wet-dry cycles in a chloride solution. At the same mechanical strength class, geopolymers shrink more than cementitious mortars if free while their low modulus of elasticity causes a lower shrinkage if mortars are restrained with bars. Pore dimensions affect the water vapor permeability, which resulted to be more pronounced in geopolymers than in cement mortars, and capillary water absorption with low values especially for fly ash geopolymers. During the first month of curing, the higher alkalinity of geopolymers matrix prolongs the active state of both black and galvanized steel bars. However, when exposed to a chloride solution, fly ash based geopolymers offer a higher protection to reinforcements than cementitious mortars.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/228044

Studio della protezione catodica di un asse portaelica mediante modellazione agli elementi finiti
Atti delle Giornate Nazionali sulla Corrosione e Protezione XI Edizione - Ferrara 15-17 giugno 2015
Autore/i: Lorenzi, S.; Pastore, T.; Bellezze, Tiziano; Fratesi, Romeo
Editore: Associazione Italiana di Metallurgia
Luogo di pubblicazione: Milano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Il lavoro riporta i risultati di uno studio della distribuzione di corrente e potenziale su un asse portaelica in acciaio inossidabile, sottoposto a protezione catodica per prevenirne la corrosione localizzata, in acqua di mare. La protezione è realizzata nell’intercapedine tra asse e astuccio, entrambi in acciaio inossidabile; la soluzione studiata prevede due anodi galvanici in acciaio al carbonio. L’articolo analizza la variazione della distribuzione in funzione delle condizioni ambientali e di movimento della nave, ossia nelle condizioni di flusso di acqua di mare e rotazione dell’albero che si realizzano durante i periodi di fermo in porto o di navigazione. Il modello numerico si basa su un modulo di calcolo agli elementi finiti; sono state simulate situazioni di esposizione dettate principalmente dalla concentrazione di ossigeno dell’acqua e dalle condizioni di flusso di acqua, senza formazione di deposito calcareo sulla superficie protetta. Il modello è confrontato con misure sperimentali rilevate su un sistema reale, con asse fermo e flusso di acqua di mare naturale nell’intercapedine.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/227501

Indagine sull’efficacia di un sistema di protezione catodica combinato ad anodi di magnesio e a corrente impressa all’interno di scaldacqua domestici ad accumulo
Atti delle Giornate Nazionali sulla Corrosione e Protezione XI Edizione - Ferrara 15-17 giugno 2015
Autore/i: Mingo, Antonio; Bellezze, Tiziano; Roventi, Gabriella; Mancini, A.; Fratesi, Romeo
Editore: Associazione Italiana di Metallurgia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In questo lavoro di ricerca è stato studiato, all’interno di uno scaldacqua di capacità volumetrica di 60L, il grado di protezione catodica offerta da un sistema combinato di anodi, costituito da un anodo sacrificale di magnesio e da un anodo a corrente impressa di titanio attivato. L’efficacia di tale sistema è stata esaminata in funzione della conducibilità specifica dell’acqua (50 µS/cm, 500 µS/cm e 1000 µS/cm) e della temperatura (20°C, 50°C e 75°C). A tale scopo, sono state realizzate sei sonde poste nei punti critici del serbatoio come le zone di saldatura. Esse hanno permesso di studiare l’efficacia della protezione catodica del boiler “in modo localizzato”, tramite misure di corrente e potenziale relative a difetti simulati. Allo scopo è stata sviluppata una stazione di monitoraggio attraverso cui venivano misurati in continuo i potenziali e le correnti parziali relative alle sei sonde, alla flangia porta-resistenza elettrica e al serbatoio dello scaldacqua. Da questo studio, è emerso che il sistema esaminato ha protetto tutte le componenti metalliche dello scaldacqua, in tutte le condizioni sperimentali. Inoltre, è stata osservata anche la sovraprotezione del sistema esaminato con probabile sviluppo di idrogeno. Al fine di eliminare questo problema e di garantire una buona gestione della protezione catodica del serbatoio smaltato, è possibile utilizzare il sistema combinato ma con l’anodo di titanio operante a corrente più bassa.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/227496

Studio sull’azione passivante prodotta dal Cr VI sull’acciaio zincato nel calcestruzzo
Atti sulle Giornate Nazionali sulla Corrosione e Protezione - XI Edizione - Ferrara 15-17 giugno 2015
Autore/i: Bellezze, Tiziano; Roventi, Gabriella; Timofeeva, Daria; Fratesi, Romeo
Editore: Associazione Italiana di Metallurgia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: E’ stato studiato l’effetto della presenza di Cr VI nel calcestruzzo sulla corrosione attiva dello zinco. Lo studio è stato effettuato monitorando il potenziale di libera corrosione delle barre zincate nel calcestruzzo e dello zinco in soluzione satura di Ca(OH)2. I risultati indicano che il Cr VI promuove la passivazione dello zinco e dell’acciaio zincato per il suo effetto inibitore sulla corrosione dello zinco. Più è alta la concentrazione di Cr VI, più breve è il tempo necessario per la passivazione dello zinco. La passivazione avviene immediatamente dopo l’immersione quando la concentrazione del Cr VI raggiunge 15 ppm rispetto al peso del cemento. Questa accelerazione evita una perdita di adesione delle barre dovuta allo sviluppo di idrogeno durante il primo periodo di immersione delle barre nel calcestruzzo, quando la pasta cementizia non è ancora indurita. Con concentrazioni di Cr VI  6 ppm, in calcestruzzo è stata osservata una riattivazione dell’acciaio zincato, seguita da una nuova passivazione; questo comportamento non avviene in soluzione satura di Ca(OH)2. Il massimo contenuto di Cr VI nel cemento permesso dalla direttiva europea 53/2003/EEC (2 ppm) non appare sufficiente ad accelerare la passivazione delle barre zincate.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/227495

Studio della protezione catodica di un asse portaelica mediante modellazione agli elementi finiti
APCE NOTIZIE
Autore/i: Lorenzi, S.; Pastore, T.; Bellezze, Tiziano; Fratesi, Romeo
Classificazione: 1 Contributo su Rivista
Abstract: l lavoro riporta i risultati di uno studio della distribuzione di corrente e potenziale su un asse portaelica in acciaio inossidabile, sottoposto a protezione catodica per prevenirne la corrosione localizzata, in acqua di mare. La protezione è realizzata nell’intercapedine tra asse e astuccio, entrambi in acciaio inossidabile; la soluzione studiata prevede due anodi galvanici in acciaio al carbonio. L’articolo analizza la variazione della distribuzione in funzione delle condizioni ambientali e di movimento della nave, ossia nelle condizioni di flusso di acqua di mare e rotazione dell’albero che si realizzano durante i periodi di fermo in porto o di navigazione. Il modello numerico si basa su un modulo di calcolo agli elementi finiti; sono state simulate situazioni di esposizione dettate principalmente dalla concentrazione di ossigeno dell’acqua e dalle condizioni di flusso di acqua, senza formazione di deposito calcareo sulla superficie protetta. Il modello è confrontato con misure sperimentali rilevate su un sistema reale, con asse fermo e flusso di acqua di mare naturale nell’intercapedine.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/228383

Metodo visivo per la misura dell'avanzamento del fronte di carbonatazione nel calcestruzzo
Autore/i: Bellezze, Tiziano; Barbaresi, Elisa; Bartolucci, Alessio; Fratesi, Romeo
Classificazione: 6 Brevetti
Abstract: Il brevetto propone un metodo innovativo per la prevenzione della corrosione delle armature in acciaio nel cemento armato. Il metodo classico di monitoraggio consiste nel prelevare campioni (carote) o realizzare campioni (provini) di calcestruzzo e misurarne lo spessore soggetto a carbonatazione in base all'interazione con una soluzione alcolica di fenolftaleina. La presente invenzione propone invece di utilizzare un metodo visivo per misurare il fronte di carbonatazione nel calcestruzzo senza impiegare carote, ottenendo risultati del tutto equivalenti a quelli ottenuti con questi elementi. Allo stesso tempo permette di ridurre al minimo il costo delle operazioni di monitoraggio e il danneggiamento per il carotaggio.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/249653

Cathodic protection of a ship propeller shaft by impressed current anodes
LA METALLURGIA ITALIANA
Autore/i: Bellezze, Tiziano; Fratesi, Romeo; Roventi, Gabriella
Classificazione: 1 Contributo su Rivista
Abstract: This work studies the application of cathodic protection by potentiostatic polarization method with impressed current anodes for preventing corrosion phenomena on ship propeller shafts made of 17-4PH stainless steel, in seawater. Tests were carried out on a full scale propeller system (more than 3 m long) by using one or two activated titanium wires placed lengthwise in the interspace between the shaft and the stern tube. In order to simulate ship navigation and ship berthed in harbour, flowing (40 L/min) and stagnant seawater were respectively considered. Both technical solutions, consisting in the use of one or two titanium anodes, were able to protect the shaft. The results are compared with the data reported in previous works with different types and geometries of the anode.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/200902

FTIR study on the amorphous corrosion products of galvanized steel in carbonated concrete
EUROCORR 2014 - Improving materials durability: from cultural heritage to industrial applications
Autore/i: Roventi, Gabriella; Bellezze, Tiziano; Conti, Carla; Fratesi, Romeo
Editore: Dechema - Associazione Italiana di Metallurgia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The composition and the structure of the passivating products of galvanized steel after concrete carbonation and wet-dry cycles in tap water were studied. The research was performed on mild steel sheets galvanized in a pure zinc bath and then embedded in cubic concrete specimens. After 39 days of air curing, the specimens were placed in a carbonation chamber and then were submitted to wet-dry cycles in tap water. After different periods of time, some concrete specimens were broken and the sheets were removed and submitted to scanning electron microscopy, energy dispersive X-ray analysis and Fourier transform infrared spectroscopy. The results confirm that concrete carbonation leads to the destruction of the passivating layer of calcium hydroxyzincate with formation of amorphous compounds. FTIR spectra indicate that these compounds are ZnCO3 and hydrozincite, with a prevailing presence of the former. SEM observations of the coating cross-sections confirm the results of previous corrosion rate measurements, which indicate that zinc remains passive both during concrete carbonation and during the subsequent wet-dry cycles in tap water. After 19 wet-dry cycles only to a slight decrease of the amount of the corrosion products on the coating surface was found by means of SEM observation and FTIR spectroscopy.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/200903

Malte geopolimeriche e cementizie a pari classe di resistenza confrontate anche in presenza di armature
Atti del 12° Convegno Nazionale AIMAT
Autore/i: Mobili, Alessandra; Giosue', Chiara; Mancini, Roberto; Bellezze, Tiziano; Tittarelli, Francesca
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Il crescente interesse nella ricerca di materiali più sostenibili ha portato allo studio di malte geopolimeriche come sostitute delle tradizionali malte a base di cemento Portland. La ricerca si è sviluppata confrontando il comportamento di malte cementizie e geopolimeriche a parità di classe di resistenza meccanica (R1 ≥ 10MPa, R2 ≥ 15MPa and R3 ≥ 25MPa). In particolare sono state confezionate tre malte geopolimeriche a base di cenere volante, con rapporto sabbia/cenere di 2.7:1 in peso, e una soluzione di silicato di sodio/idrossido di potassio 1:1 (in peso) a differente concentrazione. Le rispettive malte cementizie sono state confezionate con cemento Portland e calce idraulica come leganti e rapporto sabbia/legante di 3:1 in peso. Le sei miscele sono state confrontate valutando il comportamento a corrosione di possibili armature in acciaio nero e in acciaio zincato durante il primo mese dopo il getto. I risultati hanno evidenziato che l’alta alcalinità delle miscele geopolimeriche incrementa la corrosione di barre in acciaio zincato soltanto durante i primi giorni di stagionatura, mentre le armature in acciaio nero hanno avuto un comportamento simile a quelle immerse nelle matrici cementizie.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/194504

Studio dell’azione passivante prodotta dell’acqua ossigenata nei confronti dell’acciaio zincato in matrici cementizie
Atti del 12° Convegno Nazionale AIMAT
Autore/i: Bellezze, Tiziano; Roventi, Gabriella; Monosi, Saveria; Fratesi, Romeo
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: È ormai consolidato l’impiego dell’acciaio zincato come metodo preventivo per aumentare la durabilità delle strutture in calcestruzzo armato. Con il loro utilizzo può sorgere un problema di aderenza nella fase iniziale di indurimento, a causa dello sviluppo di idrogeno gassoso all’interfaccia tra il rivestimento di zinco e la pasta di cemento, nella fase di corrosione attiva. Comunque, dopo meno di 24 ore, il rivestimento diventa passivo ed i problemi di aderenza, in tempi relativamente brevi, risultano di minore importanza. Lo scopo del presente lavoro è stato quello di ridurre il tempo di corrosione attiva dell’acciaio zincato, in modo così da ridurre o eliminare lo sviluppo di idrogeno. Si è tentato di raggiungere tale scopo aggiungendo all’acqua di impasto quantitativi differenti di acqua ossigenata. La sperimentazione è stata effettuata mediante il monitoraggio del potenziale di corrosione delle armature zincate immerse in campioni di pasta cementizia (a/c = 0,34) e di calcestruzzo (a/c = 0,5), ottenuti con cemento CEM II A-LL 42,5R (Cr VI ≤ 2ppm), in cui l’acqua ossigenata era o assente (per confronto) o aggiunta in quantità differenti. Il tempo necessario per la passivazione dell’acciaio zincato era il parametro utilizzato per analizzare l’efficacia dell’acqua ossigenata nell’accelerare tale processo. Dai risultati ottenuti, si è verificato che l’acqua ossigenata è efficace per ridurre i tempi di passivazione delle barre d’armatura zincate. A seconda della tipologia di campioni, la percentuale minima di soluzione concentrata di H2O2 (113 volumi) da aggiungere all’acqua di impasto, per garantire la passivazione sin dalle fasi iniziali del getto, è risultata piuttosto variabile: infatti per i campioni di malta è stata necessaria una percentuale dello 0,12% in volume, mentre per i campioni di calcestruzzo una percentuale del 1%. Inoltre, i problemi riscontrati in questi getti, riguardano i non trascurabili aumenti di volume dei campioni, a causa dello sviluppo di ossigeno, proveniente dall’acqua ossigenata, e le rilevabili diminuzioni di resistenza a compressione.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/201305

Geopolymeric and cementitious mortars with the same strength class: comparison of the corrosion behaviour of embedded steel and galvanized steel reinforcements
EUROCORR 2014, Improving materials durability: from cultural heritage to industrial applications
Autore/i: Bellezze, Tiziano; Mobili, Alessandra; Roventi, Gabriella; Tittarelli, Francesca
Editore: Dechema - Associazione Italiana di Metallurgia
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Geopolymeric and cementitious mortars with the same strength class and workability were studied and compared in terms of mechanical and corrosion behaviour of possible reinforcements. To this aim, three different geopolymeric and cement mixtures were manufactured in order to obtain mortars belonging to R1 > 10MPa, R2 > 15MPa and R3 > 25 MPa strength class. In particular, mortars based on geopolymer binder were prepared with fly ash, calcium aluminate cement, a solution of sodium silicate/potassium hydroxide ratio of 0.85:1, with different concentration of KOH, and a sand/binder ratio of 2.7:1, by weight. The respective three cementitious mortar mixtures were prepared with different proportions of ordinary Portland cement and hydraulic lime as binders, different water/binder ratio by weight and the same sand/binder ratio (3:1 by weight). The corrosion resistance of steel and galvanized steel reinforcements was investigated by free corrosion potential and polarization resistance measurements. Finally, metallographic analysis on the cross sections of galvanized bars extracted from the specimens was also carried out. The results showed that, initially, the galvanized steel reinforcements are particularly susceptible to corrosion in geopolymeric mixtures due to their high alkalinity. However, after few days of curing, the corrosion rate decrease, even if this process is slower than that of same reinforcements in cementitious mixtures. On the other hand, in geopolymeric matrix, the steel reinforcements show a lower corrosion rate, if compared with galvanized steel reinforcements, and their corrosion behaviour do not change significantly with the type of binder.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/200904

Elettrodeposizione di rivestimenti compositi in lega Zn-Ni rinforzata con particelle nanometriche di SiC
Atti del 12° Convegno Nazionale AIMAT
Autore/i: Roventi, Gabriella; Bellezze, Tiziano; Giuliani, Giampaolo; Fratesi, Romeo
Editore: AIMAT
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: E’ stata studiata l’elettrodeposizione su acciaio dolce di rivestimenti in lega Zn-Ni rinforzata con nano-particelle di βSiC (∼ 60 nm). Le elettrodeposizioni sono state eseguite galvanostaticamente, con densità di corrente compresa tra 10 e 30 mA/cm2, utilizzando un bagno industriale alcalino. In assenza di SiC, sono stati ottenuti rivestimenti omogenei e compatti, aventi la struttura della fase γ (Ni5Zn21), fortemente orientata secondo la direzione (100). I rendimenti di corrente sono elevati e il contenuto di nichel è compreso tra il 12,3 e il 16,2 wt%. Aggiungendo le particelle al bagno, sono stati ottenuti depositi contenenti SiC fino al 2,2 wt%; l’incorporazione del SiC aumenta leggermente il contenuto di Ni dei depositi, ma riduce i rendimenti di corrente, che comunque rimangono superiori all’80%. L’incorporazione delle particelle di SiC determina un forte cambiamento della morfologia dei depositi, che mostrano a tutte le densità di corrente studiate un’agglomerazione nodulare dei grani. Questo effetto è attribuibile al fatto che il SiC modifica la crescita dei depositi, riducendo la loro orientazione preferenziale. L’incorporazione del SiC determina un leggero miglioramento della resistenza a corrosione dei rivestimenti, ma non un aumento della loro durezza, poiché la presenza del SiC non compensa il cambiamento strutturale indotto nel deposito.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/200906