I crescenti volumi di traffico che interessano le pavimentazioni stradali causano sollecitazioni tensionali di notevole entità che provocano danni permanenti alla sovrastruttura. Tali danni ne riducono la vita utile e comportano elevati costi di manutenzione. Il conglomerato bituminoso è un materiale multifase composto da inerti, bitume e vuoti d'aria. Le proprietà fisiche e le prestazioni della miscela dipendono dalle caratteristiche dell'aggregato, del legante e dalla loro interazione. L’approccio tradizionalmente utilizzato per la modellazione numerica del conglomerato bituminoso si basa su uno studio macroscopico della sua risposta meccanica attraverso modelli costitutivi al continuo che, per loro natura, non considerano la mutua interazione tra le fasi eterogenee che lo compongono ed utilizzano schematizzazioni omogenee equivalenti. Nell’ottica di un’evoluzione di tali metodologie è necessario superare questa semplificazione, considerando il carattere discreto del sistema ed adottando un approccio di tipo microscopico, che consenta di rappresentare i reali processi fisico-meccanici dai quali dipende la risposta macroscopica d’insieme. Nel presente lavoro, dopo una rassegna generale dei principali metodi numerici tradizionalmente impiegati per lo studio del conglomerato bituminoso, viene approfondita la teoria degli Elementi Discreti Particellari (DEM-P), che schematizza il materiale granulare come un insieme di particelle indipendenti che interagiscono tra loro nei punti di reciproco contatto secondo appropriate leggi costitutive. Viene valutata l’influenza della forma e delle dimensioni dell’aggregato sulle caratteristiche macroscopiche (tensione deviatorica massima) e microscopiche (forze di contatto normali e tangenziali, numero di contatti, indice dei vuoti, porosità, addensamento, angolo di attrito interno) della miscela. Ciò è reso possibile dal confronto tra risultati numerici e sperimentali di test triassiali condotti su provini costituiti da tre diverse miscele formate da sfere ed elementi di forma generica. / Higher traffic volume produces high stress within pavement layer, which is one of the main causes for pavement distresses. These distresses reduce the service life of the pavement and increase the maintenance cost. Asphalt mixture is a composite material of graded aggregates bound with asphalt binder plus a certain amount of air voids. The physical properties and performance of asphalt mixture are governed by the properties of the aggregate, the properties of the asphalt binder and asphalt-aggregate interactions. The conventional approach to model the stress-strain behavior of asphalt mixtures is to treat them at macro-scale using continuum-based methods. These methods represent the system as a domain of elementary units with a simple shape that, while deforming, remain in contact with each other through their relative separation surfaces. Numerous research works, however, show that for these mixtures it's very important to take into account their micromechanical behaviour at the scale of aggregate particles, because it is a primary factor in terms of overall system performance. In this way the Distinct Particle Element Method (DEM-P) represents a very useful tool, which schematizes a granular material by particles that displace independently from one another and interact only at contact points. Since the greater part of asphalt mixtures is composed of aggregates, their structure and characteristics, particularly angularity and shape, have been considered as primary factors that affect the development of the aggregate skeleton and the mechanical performance of asphalt pavements. Aggregate contact and interlocking, in fact, control the load-bearing capacity and load-transferring capability of asphalt mixes. In order to investigate this influence, a series of triaxial tests have been conducted on samples composed of spheres and angular grains. Numerical results have been compared with the lab ones in terms of deviator stress versus axial strain and in terms of micromechanical characteristics.

Il recupero dei materiali di scarto è un aspetto di grande attualità in campo stradale, così come negli altri ambiti dell’ingegneria civile. L’attenzione della ricerca e degli esperti del settore è rivolta all’affinamento di tecniche di riciclaggio che riducano l’impatto ambientale senza compromettere le prestazioni meccaniche finali. Tali indagini cercano di far corrispondere le necessità di smaltimento dei rifiuti con quelle dell’industria infrastrutturale, legate al reperimento di materiali da costruzione tecnicamente idonei ed economicamente vantaggiosi. Attualmente sono già diversi i tipi di prodotti rigenerati e riutilizzati nella realizzazione delle pavimentazioni stradali e numerosi sono anche quelli di nuova introduzione in fase di sperimentazione. In particolare, accanto ai materiali derivanti dalle operazioni di recupero della rete viaria, è opportuno considerare anche quelli provenienti dall’esercizio delle attività di trasporto, il quale comporta ogni anno il raggiungimento della fine della vita utile per centinaia di migliaia di tonnellate di pneumatici di gomma. L’obiettivo della presente analisi sperimentale è quello di fornire indicazioni e informazioni in merito alla tecnica di riciclaggio a freddo con emulsione bituminosa e cemento, valutando la possibilità di applicazione di tale metodologia in combinazione con il polverino di gomma, ottenuto dal recupero degli pneumatici fuori uso (PFU). La ricerca si distingue per una duplice valenza: la prima è quella di promuovere ulteriormente la tecnica di riciclaggio a freddo, che si sta imponendo per i suoi numerosi vantaggi economici ed ambientali, legati soprattutto alla temperatura d’esercizio; la seconda è quella di sperimentare l’utilizzo del polverino di gomma, nelle due forme di granulazione tradizionale e criogenica, additivato a miscele costituite interamente da materiale proveniente da scarifica di pavimentazioni esistenti e stabilizzate con diverse percentuali di emulsione di bitume e di legante cementizio. / Waste materials reclamation is a subject of great interest in road construction as well as in all other areas of civil engineering. Research and experts attention is focused on the improvement of recycling techniques that can reduce the environmental impact without compromising the final mechanical performances. These investigations try to match the needs of waste disposal with those of infrastructural industry, linked to obtaining building materials technically appropriate and cost effective. Currently there are several types of products already reclaimed and reused in the pavements construction and there are also those newly introduced that are still involved in the testing phase. In particular, in addition to materials resulting from the pavement recycling operations, those derived from the operation of transport activities are to be considered. They include hundreds of thousands of tons of rubber tires that every year reach the end of their life. The goal of this experimental analysis is to provide references and information on the cold recycling technique with bituminous emulsion and cement, studying the possible application of this method in combination with the crumb rubber obtained from end of life tires. The research is characterized by a dual purpose: first is to further promote the technique of cold recycling which is being imposed for its numerous economic and environmental advantages, especially related to the operating temperature; the second is to experiment the use of the crumb rubber, in the two forms obtained from traditional and cryogenic mechanical shredding, added to mixtures entirely consisting of reclaimed asphalt from milling of existing pavements and stabilized with different percentages of bituminous emulsion and cement binder.

A design can be defined as context-sensitive when it achieves effective technical and functional transportation solutions, while preserving and enhancing natural environments and minimizing impacts on local communities. Traffic noise is one of the most critical environmental impacts of transportation infrastructure and it affects both humans and ecosystems. Tire/pavement noise is caused by a set of interactions at the contact patch and it is the predominant source of road noise at the regular traffic speeds. Wearing course characteristics affect tire/pavement noise through various mechanisms. Furthermore, acoustic performance of road pavements varies over time and it is influenced by both aging and temperature. Three experimentations have been carried out to evaluate wearing course characteristics effects on tire/pavement noise. The first study involves the evaluation of skid resistance, surface texture and tire/pavement noise of an innovative application of multipurpose cold-laid microsurfacing. The second one involves the evaluation of the surface and acoustic characteristics of the different pavement sections of the test track of the Centre for Pavement and Transportation Technology (CPATT) at the University of Waterloo. In the third study, a set of highway sections have been selected in Southern Ontario with various types of pavements. Noise measurements were carried out by means of the Statistical Pass-by (SPB) method in the first case study, whereas in the second and in the third one, Close-proximity (CPX) and the On-Board Sound Intensity (OBSI) methods have been performed in parallel. Test results have contributed to understand the effects of pavement materials, temperature and aging on tire/pavement noise. Negligible correlation was found between surface texture and roughness with noise. As a general trend, aged and stiffer materials have shown to provide higher noise levels than newer and less stiff ones. Noise levels were also observed to be higher with temperature increase.

Molteplici studi, portati a termine di recente in Europa ed oltreoceano, hanno focalizzato l’attenzione sulle problematiche indotte dal trasporto merci in ambito urbano e contribuito ad identificarne possibili soluzioni (city logistics). Le aree urbane, dovrebbero idealmente essere luoghi ove abitare, svolgere attività economiche, sociali e ricreative. Esse possono vedere compromessa la loro predisposizione a tali scopi anche a causa del crescente traffico delle merci, il cui trasporto è effettuato principalmente su gomma, per via delle brevi distanze da coprire e delle carenze infrastrutturali. I veicoli commerciali, ad eccezione di quelli di ultima generazione, incidono negativamente sulla qualità dell’ambiente urbano, generando inquinamento atmosferico e acustico. La politica del “just in time”, che prevede l’assenza di magazzini di stoccaggio delle merci, incrementa i movimenti commerciali. Nella presente tesi vengono trattati alcuni aspetti logistici di regolamentazione della sosta e degli accessi per i mezzi di trasporto merci, in grado di rendere più efficiente la distribuzione dei beni, mitigando le problematiche indotte dal traffico e, quindi, salvaguardando la qualità di vita nei centri cittadini.

Lo studio effettuato pone le sue basi sulla ricerca di materiali stradali che combinino ad elevati standard prestazionali, la riduzione dell’impatto ambientale in fase realizzativa e manutentiva. In particolare il seguente lavoro si occupa dello studio di 7 leganti modificati con polimeri ed additivati con cere. I primi infatti conferiscono alla miscela maggiore elastoplasticità, incrementandone la durabilità e la resistenza a fatica. Nei secondi la presenza del materiale paraffinico contribuisce a ridurre la viscosità del bitume, consentendo un notevole abbassamento della temperatura di produzione e stesa della miscela. Numerosi studi hanno dimostrato che le caratteristiche meccaniche della pavimentazione sono fortemente influenzate dal grado di ossidazione delle componenti organiche del bitume, ovvero dal fenomeno dell’invecchiamento o aging. Pertanto allo studio reologico del bitume, si sono affiancate prove di simulazione dell’ invecchiamento nel breve e lungo termine. In fase di ricerca sperimentale si sono analizzati i leganti modificati ed additivati secondo la teoria della viscoelasticità, simulando le reali condizioni di carico ed invecchiamento alle quali il bitume è sottoposto. Tutte le prove di caratterizzazione reologica avanzata sono state effettuate mediante l’utilizzo del DSR (Dynamic Shear Rheometer - UNI EN 14770 ) in varie configurazioni di prova e l’invecchiamento a breve termine è stato simulato mediante RTFOT (Rolling thin film oven test -UNI EN 12607-1). Si è proposto inoltre una nuova procedura di aging invecchiando il bitume alla temperatura di Twork, ovvero a quel valore della temperatura tale per cui, in fase di messa in opera, si avrà una distribuzione molecolare omogenea del modificante all’interno del bitume. / The use of modified asphalt binders in hot-mix asphalt has steadily increased over the past several decades. Modified asphalt binders currently make up over 20% of paving grade asphalt laid in all over the world, and the percentage continues to grow. In these recent years, the Warm Mix Asphalt (WMA) are spreading widely in the new road constructions and pavement rehabilitations. The main intent of WMA is to produce mixtures with similar strength, durability, and performance characteristics as traditional hot mixes using substantially reduced production temperatures. The pavement technology combine the use of polymer with the warm additive, that it will be the main core of this research. However, selecting appropriate temperatures for handling these binders has been an issue with the use of wax – polymer modified asphalt binders. The traditional method of determining appropriate mixing and compaction temperatures for an asphalt binder is based on relatively simple viscosity measurements of the asphalt. However, this method often yields excessively high temperatures for many modified binders that have caused concerns with degradation of the binder’s properties and emission problems in laboratories during preparation of samples and during production and placement of asphalt mixtures in the field.

“[…]Landscape” means an area, as perceived by people, whose character is the result of the action and interaction of natural and/or human factors; […]Acknowledging that the landscape is an important part of the quality of life for people everywhere: in urban areas and in the countryside, in degraded areas as well as in areas of high quality, in areas recognised as being of outstanding beauty as well as everyday areas[…]”. The starting point of this research is the innovative definition of landscape, given by the “European Landscape Convention”, that draws the attention to the need of: - examining the territory as a spatial and temporal continuity; - considering the territory transformations as a value; - giving equal dignity to ruined territory, refusing the idea that only beautiful landscape deserve to be protected. Among the several and diverse European studies on infrastructure and landscape relation, the research focuses on marginal areas created by the infrastructure for mobility (road and highway) in the landscape. These areas are lacking a clearly defined function, they are not anymore part of the landscape, but they have not become part of the infrastructure. These areas are defined as infrastructural refuses. The attention is shifted from the design of the road and from the aesthetic of mobility to the new spaces created by the infrastructure in the landscape. Moreover, the research tries to analyze the infrastructural refuses only ex-post, when these spaces have already been created by the construction and use of a road, or theoretically created in-fieri by an infrastructure project that has overlooked these areas, forgetting to design them, or simply not taking into account their existence. The first part of the research is devoted to define the identity of the infrastructural refuse through the critical analysis of the main theories of the protagonists of the international debate supported by the identification of literature related to the topic. The infrastructural refuse is then described through analytical tools (morphology and perception) that show the effects of infrastructural transformation focussing mainly on mobility infrastructure transformation in Trentino Alto-Adige. The case study analyzed is the trunk road 12 on the stretch called Tangenziale di Trento, and more specifically the transformation caused by the junctions close to urban areas. The Tangenziale is a great artery of traffic that often cuts through the surrounding areas leading to real marginal areas. The research then proceeds to the definition of refuse as a value and tries to highlight its potential for transformation mainly by analyzing the strategy of recycling. Different types of re-use of infrastructural refuses are described: the artistic-temporary use, the daily spontaneous use by the population, and finally the illegal use. The research analyzes the mobility infrastructural refuses: outlining possible transformations, design, re-inventions; illustrating the unexpressed features of the places; re-drawing with different connotation signs that have lost their original meaning; eventually reaching the “operatività dello scarto”. Negative actions like abandon, refuse, waste can become occasions to re-shape and re-think the landscape. The results of the research show the possibility to re-think the infrastructural refuse spaces as a reserves of soil, suggest alternatives to the mentality of the compensation and mitigation, calling for the evolution of the protocols of mobility infrastructure design.

This PhD thesis provides design strategies to control changes produced in mountains places and landscapes following constructions of roads. Strategies are based on the activation of unexpressed potentialities in places, although compromised, characterized by presence of roads. With the term unexpressed potentialities we refer to functions, attitudes, uses which, during the process of road realization, have not found an appropriate design solution. Topic of the thesis is to demonstrate that these design gaps can be properly addressed by an architecture project, obtaining two results: create a link between places, landscapes and roads and consolidate the participation of architecture discipline in a field (roads production) in which, today in Italy, it is less integrated than others. Changes in mountain landscapes are characterized by morphology and orography of the territory crossed: the factor that most influences in this direction is the verticality of the space. This specificity is discussed in the thesis through the analysis of road segments, infrastructure nodes or other specific situations, divided according to the topography in which there are: high gradients, slope or bottom of valleys. Specific characteristics which correspond to the three different orographic situations are explained by an interpretative study of the cross section, highlighting the potentiality of the space related with its vertical dimension. Most study cases belong to the geographical area of Trentino Alto Adige, an Italian region characterized by mountain landscapes. Some study cases are taken from other Italian regions or known experiences of the international context. The proposed strategies are developed through study of architectural projects, joined by devices that interpret the vertical (overlapping, slope and difference in altitude) of the spaces, reproposable in cases of mountain road. All strategies can be applied at any step of road production, from concept to design to construction. In addition, and we assume that this is the most frequent case, can be applied ex post, when the road is built, intervening to change situations already in place.