Search results for " ferro"
showing 10 items of 499 documents
Effect of mixing time on reclaimed asphalt mixtures: An investigation by means of imaging techniques
2015
This paper presents an application of imaging techniques to investigate the distribution of reclaimed asphalt and air voids within gyratory compacted specimen. Stone Mastic Asphalt specimens containing reclaimed asphalt, were produced at five different laboratories participating in the collaborative project Re-Road: University of Nottingham, Belgium Road Research Centre, Danish Road Directorate, TU Braunschweig and Laboratoire Centrale de Ponts et Chaussees (now IFSTTAR). This study applies the X-ray Computed Tomography and Optical Microscopy techniques to view the internal structure of the specimen with particular focus on the air voids and reclaimed asphalt distributions within the specim…
Grain growth in Na 0.5 Bi 0.5 TiO 3 -based solid solutions
2019
This paper discusses effects of different dopants, sintering technique and parameters on microstructure and properties of pure and Yb, Er-doped Na0.5Bi0.5TiO3 (NBT). All stoichiometric compositions follow the abnormal grain growth mechanism (AGG) and exhibit a bimodal grain size distribution. Bi over-stoichiometry, two step sintering and hot pressing are effective inhibitors of AGG. Microstructure of sintered NBT greatly influences such properties as dielectric permittivity and depolarization temperature.
Tyre rubber-modified bitumens development: the effect of varying processing conditions
2013
Tyre rubber-modified binders (TR-MBs), produced through McDonald’s wet process and used worldwide (e.g. asphalt rubber), have been demonstrated to provide various benefits to pavements and, moreover, they represent a good opportunity for recycling tyre rubber (TR). However, this technology is still struggling to be fully adopted in Europe, mainly because of their poor stability during high temperatures storage, which leads to high initial costs in modifying existing asphalt plants. Storage stable TR-MBs are proving to be a great option and their development could be the key to spread the recycling of TR within paving applications in Europe. This paper aims to enrich this field of research b…
Project duration evaluated using affine arithmetic
2016
A civil engineering work can be performed by organizing the available resources (manpower, equipment and materials) in many different ways. Each different configuration results in a realization time and a cost that a building company has to bear. To produce reliable duration forecasts and money savings, it is essential to take into account all the uncertainties involved in the project operations. Generally, since it is impractical to process numerous uncertain variables - also undefined from a statistical point of view -, traditional probabilistic methods involve application difficulties for complex environments such as construction sites. To properly handle this issue, the authors propose …
An advanced pavement management system based on a genetic algorithm for a motorway network
2013
Maintenance and improvement, through the rehabilitation, of the road infrastructure is a strategic and priority objective for road agencies, nevertheless the economic resources required are often inadequate. Within road management, the pavement management system (PMS) plays an essential role because of both the money needed and the performance that should be provided in terms of safety, ride quality and transport cost. The PMS is based on searching for a balanced solution between the lowest cost and the increased level of performance (i.e. pavement condition). In this paper a PMS multi-objective optimization method, was proposed, using a genetic algorithm (GA) to identify the best solution …
The Emergence of Arboriculture in the 1st Millennium BC along the Mediterranean’s “Far West”
2021
This paper presents the history of the introduction and expansion of arboriculture during the 1st millennium BC from the South of the Iberian Peninsula to the South of France. The earliest evidence of arboriculture at the beginning of the 1st millennium hails from the south of the Iberia from where it spread northward along the peninsula’s eastern edge. The different fruits (grape, olive, fig, almond, pomegranate and apple/pear) arrived together in certain areas in spite of uneven distribution and acceptance by local communities. Grape was the crop with the greatest diffusion. The greater diversity of crops in the southern half of the peninsula is also noteworthy. Their development paved th…
Editorial: Calculation of Passenger Car Equivalents at Roundabouts
2021
Editorial on the Research Topic: Calculation of Passenger Car Equivalents at Roundabouts About this Research Topic: Calculation of Passenger Car Equivalents (PCEs) for heavy vehicles represents the starting point for the operational analysis of road facilities and other traffic management applications. PCEs are used to consider the presence of heavy vehicles in the traffic stream and are expressed as multiples of the effect of an average passenger car. Moreover, the highly curvilinear nature of the roundabout design, both in urban and rural environment, has significant effects on the paths that heavy vehicles would travel; as a consequence, the interaction between the physical and performan…
Effect of ageing on the morphology and creep and recovery of polymer-modified bitumens
2018
Polymer additives are used to improve the properties of road bitumens including their oxidative resistance. However, their usage as anti-oxidative materials remains relatively unclear. This study aims to investigate the changes in the morphology and the rheological response of polymer modified bitumens used in road pavement construction caused by ageing. An elastomer (radial styrene butadiene styrene, SBS) and a plastomer (ethyl vinyl acetate, EVA) polymer were mixed with one base bitumen at three polymer concentrations. The bitumens were RTFO and PAV aged. The morphology of the bitumens was captured by fluorescence microscopy while the rheological properties were measured by means of the m…
Evaluating the safety of platooned heavy vehicles: A case study
2016
In the right lane of motorways with trucks' overtaking prohibition is very common the formation of platoons of heavy vehicles. Although this traffic controls strategies can increase the capacity of passing lane, in the right lane may occur increases of rear-end collisions. The purpose of this research was to evaluate the safety of the platooned heavy vehicles by means a closed-form stream model. The case study of the Italian motorway A22 was examined. The sampling of platoons was performed in four observation sections.In the research have been investigated platoons with 2/20 heavy vehicles for each platoon. Many traffic parameters have been evaluated: frequencies of the number of platoons, …
A model to evaluate heavy vehicle effect in motorway traffic flow
2017
Highway operating conditions are also determined by interactions between passenger cars and heavy vehicles in the flow. Therefore, a suitable model which describes and predicts the heavy vehicle effect can be useful to achieve more realistic criteria to evaluate the Level of Service (LOS) for infrastructures in the uninterrupted flow. After reviewing briefly the models available in literature to take account of the effects on operating conditions due to heavy vehicles, the paper examines some traffic data analysis of the Italian A22 motorway and later presents a closed-form traffic model for heavy vehicles via the queuing theory. Some applications of this model are displayed for operational…