Search results for " ferro"
showing 10 items of 499 documents
Studio di conglomerati bituminosi con granulato di gomma proveniente da pneumatici dismessi
2002
La ricerca di conglomerati bituminosi di elevate prestazioni sovente si associa allo studio delle implicazioni ambientali che la produzione, la posa in opera e l’esercizio di tali materiali comportano. Un aspetto assai importante, in tal senso, è l’opportunità che alcune modalità produttive offrono in termini di un ridotto consumo di inerti e del contestuale impiego di materiali destinati a discarica che, invece, vengono inseriti in processi di riciclaggio. È questo il caso della gomma proveniente dal riciclaggio industriale di pneumatici dismessi che, negli Stati Uniti ed in Canada, è divenuta una fonte sostanziosa per la realizzazione di conglomerati bituminosi. La presente ricerca, dopo …
Asphalt mixtures improved with plastic additives: mix design and case study in an airport
La crescente domanda di prestazioni e le esigenze di salvaguardia dell’ecosistema spingono a sviluppare nuove tecnologie di lavorazione, a sperimentare l’impiego di nuovi materiali, a migliorare i metodi di progetto delle miscele. Il criterio seguito è quello di un impiego più razionale delle risorse e dell’utilizzo di tecniche a basso impatto ambientale. Per ragioni tecniche ed economiche stiamo assistendo al fenomeno di espansione nel mercato degli additivi, impiegati nella produzione di miscele bituminose per migliorarne le prestazioni e ridurre i costi. In generale, però riuscire a soddisfare tutti gli obiettivi con un unico prodotto è difficile, perché l’alta qualità richiede costi più…
EMISSION FACTORS, VEHICLE MODAL ACTIVITY AND ROAD OPERATIONS. A MESOSCOPIC APPROACH
2009
Current studies underline that vehicle emissions are highly linked to modal vehicle activity and a modal approach to traffic-related air quality modeling is suitable to estimate mobile source contribution to air quality. Pollutant emissions depend on characteristics of vehicles in traffic flow and on road operating conditions predictable after the implementation of the road project; then, the usual emission rate models do not predict properly the on-road vehicles emissions of modal traffic events, such as those ones occurring at intersections. Moreover modal activity analysis carried out at micro scale level, as required by modal emission models, will be still necessary to value reliable em…
Life cycle assessment of low temperature asphalt mixtures for road pavement surfaces: A comparative analysis
2018
The increasing fuel consumption demand, the accelerated pressure imposed by the depletion of 5 scarce raw materials and the urgent environmental protection requirements are forcing the change of 6 pavement industry and academia community’s research endeavors towards the development of low 7 emissions road paving technologies able to significantly reduce mixing and compaction temperature as 8 well as the consumption of virgin raw materials. One set of relatively recent technologies in the field of 9 pavement materials that aims at addressing those concerns are the warm mix asphalt (WMA). In fact, 10 they have the potential to allow the reduction of energy consumption and airborne emissions d…
A systematic assessment of road pavement sustainability through a review of rating tools
2017
Pavements are engineered systems present in every modern society, and they have significant environmental, economic and social impacts. In an effort to promote more sustainable decisions regarding pavement design, construction and management, several pavement sustainability assessment tools have been developed. This research reviewed some of these tools and found that many of them do not treat the pavement as a system; instead, they seek to optimize individual aspects of the pavement in an effort to increase its sustainability. Therefore, a framework for analytically assessing the system outcomes towards sustainable objectives is presented and applied for modern pavement sustainability asse…
Production of innovative, recycled and high-performance asphalt for road pavements
2010
Abstract The paper deals with a specific laboratory study aiming at perfectioning recycled asphalt with high mechanical performance, for surface and structural layers of flexible pavements. The aim of the research was to combine in the same material the maximum possible quantity of recycled asphalt (RA), coming from degraded asphalt layers, together with high structural performance of the recycled mixtures obtained (mainly stability, load spreading properties, rutting and fatigue resistance) that should not be lower, or possibly better than those offered by traditional asphalt mixture, made with virgin binder and aggregate. For this purpose, innovative recycled mixtures, close-graded and wi…
Automatic Segmentation and Enhancement of Pavement Cracks Based on 3D Pavement Images
2019
Pavement cracking is a significant symptom of pavement deterioration and deficiency. Conventional manual inspections of road condition are gradually replaced by novel automated inspection systems. As a result, a great amount of pavement surface information is digitized by these systems with a high resolution. With pavement surface data, pavement cracks can be detected using crack detection algorithms. In this paper, a fully automated algorithm for segmenting and enhancing pavement crack is proposed, which consists of four major procedures. First, a preprocessing procedure is employed to remove spurious noise and rectify the original 3D pavement data. Second, crack saliency maps are segmente…
Automated highway systems and hard-shoulders running: A case study
2016
The purpose of this research was to evaluate the increase of capacity of existing motorway resulting from the implementation of relatively new traffic control strategies, as the automated highway systems (AHS) and the hard-shoulder running (HSR). Was examined the Italian motorway A22, belonging to Trans-European Road Network, corridor Helsinki - La Valletta. Many traffic surveys were done (year 2014) in several road sections. For each of them have been carried out the flow diagrams, the traffic flow parameters (capacity C, free flow speed vf,jam density kjam) and the relationship between flow rate of lane (right lane Qright and passing lane Qpass) and total flow rate Qt. The current carriag…
Modeling traffic safety at urban four leg-signalized intersections
2013
According to the state-of-the-art of the methodologies, the development of safety performance functions (SPFs) for road sections and intersections requires the employment of statistical models to predict expected crash frequencies on the basis of traffic volumes and site characteristics to be surveyed and used as input to models. Nevertheless, literature reports several studies on issues deriving from data features or methodological approaches that may invalidate the efficiency of the models and the accuracy of the estimates. Drawing inspiration from the above mentioned considerations, the objective of this study is to develop safety performance functions for a sample of urban four leg-sign…
Performance Analysis of Basic Turbo-Roundabouts in Urban Context
2012
AbstractA turbo roundabout is a new type of canalized multilane intersection in which the physical separation between lanes helps to prevent side collisions when crossing the roundabout. This paper presents an estimation of capacity, delays and level of service of basic turbo roundabouts in undersaturation conditions, considering both vehicle flow and pedestrian traffic. The traffic performance model was developed by evaluating the capacity for each entry lane. Owing to the geometric features of the intersection, the total entry capacity is obtained by considering different values of the pedestrian impedance factor and degree of saturation at both the right-turn and left-turn lanes.