According to most recent surveys, 265 mil tonnes of asphalt for road applications were produced in the European area in 2014. In the same year, the amount of available RAP was more than 50 mil tonnes. The use of RAP in new blended mixes reduces the need of neat bitumen, making RAP recycling economically attractive. In spite of its economic and environmental benefits, the use of RAP is often subjected to restrictive policies pursued by agencies due to uncertainty related to RAP mixes field performances. This thesis focuses on the effects of RAP on performances and durability of new asphalt mixes produced incorporating RAP with a standard hot-in-plant process. The influence of RAP being incorporated in new mixes was investigated through an extensive laboratory testing campaign on asphalt mixtures and on bitumen recovered from the same mixes. A specific typology of asphalt mixture has been produced with different RAP percentages of 10%, 20% and 30%. In the first phase of the research, asphalt materials have been characterized and compared in terms of resistance to fatigue, stiffness and volumetric properties. The second phase of the research aims to investigate the effects of RAP on asphalt binder as a composite blend of neat and RAP bitumen. Bituminous samples have been recovered from asphalt samples tested in phase 1 and then have been studied and compared with standard and dynamic laboratory tests. Findings show that HMA can be successfully produced incorporating up to 20% of RAP in the fresh mix. For these percentages of RAP being recycled, no negative effects on performances and durability of recycled mixtures have been noted. However, the final bitumen grade of the mix may be adjusted if more than 20% of RAP is added. Furthermore, practical implications regarding production methods and paving of RAP mixes are proposed.

Il lavoro di ricerca presentato si concentra sullo sviluppo e l’applicazione a casi reali di una tecnica innovativa a base geostatistica per la stima della curva di durata delle portate in bacini non strumentati. Prendendo spunto dalle tecniche di regionalizzazione classiche basate sul metodo del deflusso indice, la metodologia proposta stima le curve di durata adimensionali nel sito non strumentato di interesse utilizzando uno schema di ponderazione kriging di curve empiriche costruite per sezioni idrometriche localizzate nelle vicinanze del sito stesso. Nel primo caso di studio, che ha riguardato una porzione limitata di territorio appenninico marchigiano comprendente 18 bacini idrografici strumentati, si è visto che la metodologia proposta presenta prestazioni confrontabili o nettamente migliori rispetto a tecniche di regionalizzazione statistica che rappresentano lo stato dell’arte dei metodi regionali per la stima delle curve di durata. Nel secondo la metodologia proposta è stata applicata negli Stati Uniti sud-orientali e confrontata con una tecnica regionale di regressione lineare dei quantili, che è quella di riferimento proposta dal USGS. L’obiettivo è la valutazione delle prestazioni delle metodologia per un'area molto vasta che comprende 182 stazioni idrometriche nel Sud-Est degli Stati Uniti. Nella terza applicazione la metodologia proposta è utilizzata come strumento di correzione di serie idrometriche in un'area di studio del Tirolo (Austria/Italia), prodotte da modelli-afflussi capaci di simulare serie continue di portata media giornaliera. In questo contesto la metodologia è stata accoppiata ad una tecnica innovativa che stima una curva di durata dei residui, ossia la curva risultante dalla differenza tra la curva empirica e stimata con il metodo proposto, nel sito di interesse e ricostruisce una serie modificata di deflussi partendo dalla serie simulata dal modello. / The research work focuses on the design and development of a novel geostatistical approach for the prediction of flow duration curves in ungauged basins. Inspired by classical regionalization techniques based on the “index- low” method, the proposed approach is capable of predicting unbiased dimensionless flow-duration curves in ungauged sites by using a traditional kriging linear-weighting scheme of empirical curves that can be constructed at gauged sistes located in the neighborhood of the target site. The geostatistical weights are obtained by implementing an interpolation procedure of a point index that describes shape and main features of the curve. The procedure has been tested on three different case studies through three applications. The first case study, which covered a limited portion within the Marche Region, includes 18 gauged river basins and focused on the general applicability of the proposed approach. The main outcome is that the proposed method performs as well as or better than the statistical regionalization techniques representing the state of the art for the prediction of flow-duration curves. The second application focuses on a comparison with a multivariate regional technique based on linear regression analysis, which is the reference approach implemented by the USGS. The final aim of this experiment is to evaluate the performances of the methodology for a vast area that includes 182 streamgauges in the South-East of United States. In the third application, the prediction of flow-duration curves in ungauged sites is used as a correction tool for daily streamflow series obtained through continuous rainfall-runoff simulation. In this context, the methodology has been blended with an innovative technique that estimates a “residual-duration curve” for the target site and reconstructs a modified runoff series from the simulated one.

This thesis proposes the use of new methodologies for prediction of performances of asphalt mixtures. Recent improvements in technology make it possible to adopt new methods of investigation with the dual objective of improving the performance in the survey of the parameters and investigate new properties so far not analyzed. In particular, the image analysis and the tyre/surface interaction belong to an innovative framework, which is next to flank, if not replace, the classic measurements so far employed. The thesis deals with the use of these technologies for the analysis of three rubberized stone mastic asphalts, which were laid on a stretch of road close to Bologna, Italy. Three different surveys were carried out on site during the first year of service. The surveys included the change in texture and skid resistance due to the traffic, along with the acoustic properties of the pavement. Local as well as dynamic continuous measurements were carried out, involving the use of a profilometer and a skiddometer. A second phase involved the prediction of the surface parameters with different stages of simulated trafficking on Road Test Machine. At each stage change in macrotexture, skid resistance, adhesion between bitumen and aggregates, contact pressures and areas were assessed. The image analysis is used for the assessment of the adhesion between the bitumen and the aggregate. The images are then processed in order to create 3D models of the asphalt specimens and investigate the surface and volume properties. The tyre/pavement interaction is another fundamental phenomena that received little considerations from the research, given its importance. A final discussion summarizes these investigations by separately review three different simulated periods, i.e. the early life, the in-service equilibrium and the end of life. In order to accelerate the distress, one slab was subjected to Immersion Wheel Track test.

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La presente tesi di dottorato si propone lo sviluppo di un modello spazialmente distribuito per produrre una stima dell'erosione superficiale in bacini appenninici. Il modello è stato progettato per simulare in maniera fisicamente basata il distacco di suolo e di sedimento depositato ad opera delle precipitazioni e del deflusso superficiale, e si propone come utile strumento per lo studio della vulnerabilità del territorio collinare e montano. Si è scelto un bacino collinare dell'Appennino bolognese per testare le capacità del modello e verificarne la robustezza. Dopo una breve introduzione per esporre il contesto in cui si opera, nel primo capitolo sono presentate le principali forme di erosione e una loro descrizione fisico-matematica, nel secondo capitolo verranno introdotti i principali prodotti della modellistica di erosione del suolo, spiegando quale interpretazione dei fenomeni fisici è stata data. Nel terzo capitolo verrà descritto il modello oggetto della tesi di dottorando, con una prima breve descrizione della componente afflussi-deflussi ed una seconda descrizione della componente di erosione del suolo. Nel quarto capitolo verrà descritto il bacino di applicazione del modello, i risultati della calibrazione ed un'analisi di sensitività. Infine si presenteranno le conclusioni sullo studio.

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In order to protect river water quality, highly affected in urban areas by continuos as intermittent immissions, it is necessary to adopt measures to intercept and treat these polluted flows. In particular during rain events, river water quality is affected by CSOs activation. Built in order to protect the sewer system and the WWTP by increased flows due to heavy rains, CSOs divert excess flows to the receiving water body. On the basis of several scientific papers, and of direct evidences as well, that demonstrate the detrimental effect of CSOs discharges, also the legislative framework moved towards a stream standard point of view. The WFD (EU/69/2000) sets new goals for receiving water quality, and groundwater as well, through an integrated immission/emissions phylosophy, in which emission limits are associated with effluent standards, based on the receiving water characteristics and their specific use. For surface waters the objective is that of a “good” ecological and chemical quality status. A surface water is defined as of good ecological quality if there is only slight departure from the biological community that would be expected in conditions of minimal anthropogenic impact. Each Member State authority is responsible for preparing and implementing a River Basin Management Plan to achieve the good ecological quality, and comply with WFD requirements. In order to cope with WFD targets, and thus to improve urban receiving water quality, a CSOs control strategy need to be implemented. Temporarily storing the overflow (or at least part of it) into tanks and treating it in the WWTP, after the end of the storm, showed good results in reducing total pollutant mass spilled into the receiving river. Italian State Authority, in order to comply with WFD statements, sets general framework, and each Region has to adopt a Water Remediation Plan (PTA, Piano Tutela Acque), setting goals, methods, and terms, to improve river water quality. Emilia Romagna PTA sets 25% reduction up to 2008, and 50% reduction up to 2015 fo total pollutants masses delivered by CSOs spills. In order to plan remediation actions, a deep insight into spills dynamics is thus of great importance. The present thesis tries to understand spills dynamics through a numerical and an experimental approach. A four months monitoring and sampling campaign was set on the Bologna sewer network, and on the Navile Channel, that is the WWTP receiving water , and that receives flows from up to 28 CSOs during rain events. On the other hand, the full model of the sewer network, was build with the commercial software InfoWorks CS. The model was either calibrated with the data from the monitoring and sampling campaign. Through further model simulations interdependencies among masses spilled, rain characteristics and basin characteristics are looked for. The thesis can be seen as a basis for further insighs and for planning remediation actions.

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No description available.

Water distribution networks optimization is a challenging problem due to the dimension and the complexity of these systems. Since the last half of the twentieth century this field has been investigated by many authors. Recently, to overcome discrete nature of variables and non linearity of equations, the research has been focused on the development of heuristic algorithms. This algorithms do not require continuity and linearity of the problem functions because they are linked to an external hydraulic simulator that solve equations of mass continuity and of energy conservation of the network. In this work, a NSGA-II (Non-dominating Sorting Genetic Algorithm) has been used. This is a heuristic multi-objective genetic algorithm based on the analogy of evolution in nature. Starting from an initial random set of solutions, called population, it evolves them towards a front of solutions that minimize, separately and contemporaneously, all the objectives. This can be very useful in practical problems where multiple and discordant goals are common. Usually, one of the main drawback of these algorithms is related to time consuming: being a stochastic research, a lot of solutions must be analized before good ones are found. Results of this thesis about the classical optimal design problem shows that is possible to improve results modifying the mathematical definition of objective functions and the survival criterion, inserting good solutions created by a Cellular Automata and using rules created by classifier algorithm (C4.5). This part has been tested using the version of NSGA-II supplied by Centre for Water Systems (University of Exeter, UK) in MATLAB® environment. Even if orientating the research can constrain the algorithm with the risk of not finding the optimal set of solutions, it can greatly improve the results. Subsequently, thanks to CINECA help, a version of NSGA-II has been implemented in C language and parallelized: results about the global parallelization show the speed up, while results about the island parallelization show that communication among islands can improve the optimization. Finally, some tests about the optimization of pump scheduling have been carried out. In this case, good results are found for a small network, while the solutions of a big problem are affected by the lack of constraints on the number of pump switches. Possible future research is about the insertion of further constraints and the evolution guide. In the end, the optimization of water distribution systems is still far from a definitive solution, but the improvement in this field can be very useful in reducing the solutions cost of practical problems, where the high number of variables makes their management very difficult from human point of view.