https://arpi.unipi.it/bitstream/11568/798598/2/polacco%20798598.pdf

A review of the fundamentals of polymer-modified asphalts: Asphalt/polymer interactions and principles of compatibility

Morphology, rheology, and physical properties of polymer-modified asphalt binders

Using waste plastic bottles as additive for stone mastic asphalt

Although there have been a number of recent reviews on the use of traffic conflict techniques (TCTs), none have focused on the use of proximal surrogate indicators. This paper comprehensively reviews the development and application of proximal surrogate safety indicators to address this gap. There is a particular focus on more recent advancements in the application of such indicators. For each of the main indicators reviewed, the paper provides a synthesis of the main guiding principles, as well as the most prominent features, including critical or threshold values used in the past. In addition, the main advantages and disadvantages of the reviewed indicators are highlighted. Finally, a number of research gaps are identified together with recommendations for potentially useful avenues of future research.

Application of proximal surrogate indicators for safety evaluation: A review of recent developments and research needs

http://eprints.um.edu.my/8767/1/A_review_of_using_waste_and_virgin_polymer_in_pavement.pdf

A review of using waste and virgin polymer in pavement

The increase in road traffic during the last two decades in combination with an insufficient degree of maintenance due to shortage in funds has caused an accelerated and continuous deterioration of the road network in Jordan. To alleviate this process, several types of measures may be effective, e.g., securing funds for maintenance, improved roadway design, use of better quality of materials and the use of more effective construction methods. The use of polymer in asphalt mixture as a modifier started in the 80s of the last century and has been tested in a number of countries around the World. In this research, polyethylene as one sort of polymers is used to investigate the potential prospects to enhance asphalt mixture properties. The objectives also include determining the best type of polyethylene to be used and its proportion. Two types of polyethylene were added to coat the aggregate [High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE)]. The polymers were introduced to the mixture in two states (Grinded and not Grinded). Marshall mix design was used, first to determine the optimum bitumen binder content and then further to test the modified mixture properties. In total, 105 samples were prepared (21 samples were used to determine the binder content and the remaining samples were used to investigate the effect of modifying the asphalt mixtures). The optimum asphalt content was 5.4%. Seven proportions of polyethylene of each type and state by weight of the optimum binder content were selected to be tested (6, 8, 10, 12, 14, 16 and 18%). The tests include the determination of bulk density, stability and flow. Marshall mix design requires the determination of the percentages of air voids and air voids of mineral aggregate. The results indicated that grinded HDPE polyethylene modifier provides better engineering properties. The recommended proportion of the modifier is 12% by the weight of bitumen content. It is found to increase the stability, reduce the density and slightly increase the air voids and the voids of mineral aggregate.

The Use of Polyethylene in Hot Asphalt Mixtures

This study is aimed at improving the current Swedish Traffic conflicts Technique [TCT] in relation to vehicle-pedestrian conflicts. The present definition of conflict severity appears to produce less severe conflicts than they might be, particularly if the relevant road user (RRU) is the pedestrian. Another aim is to apply the Swedish TCT in Jordan as a method for evaluating safety conditions at junctions. The difference in conflict perception in the two countries is explored throughout this thesis.

The study was based on collecting data [accident, conflict, and traffic volume] from selected junctions with and without signal control in urban areas (20 junctions in Sweden and 22 junctions in Jordan). Alternative definitions of traffic conflicts and RRU were validated against the present definition of serious conflicts.

The results indicated that the present definition of serious conflicts could be improved. The most valid definition of conflicts for non-signalised or signalised junctions or both junction types together was obtained by shifting the present threshold to the more severe direction of the time to accident-speed graph by 0.25 seconds. The present definition of RRU (road-user who acted evasively and was subjected to the least sever situation) produced the most valid definition for non-signalised junctions. The high definition of RRU (the road-user who in the situation produced the highest severity, i.e. the driver) produced the most valid definition for signalised junctions. Sub-groups of conflicts were formed according to the present definition of conflicts by excluding conflicts that involved RRU under the high definition who is driving at a speed less than 20km/h. They produced accident predictions as those produced by the most valid definition of conflicts, particularly for non-signalised junctions. The results indicated that the most valid definitions in Jordan were not the most valid definitions in Sweden. Some conflict definitions, however, have high validity for non-signalised junctions in both countries. The technique must take into account the local conditions in order to be applicable in other countries. According to this study, a minimum requirement is to establish local conversion factors between accidents and conflicts, if the technique is to be applied for accident prediction purposes. Finally, the road-user perception of conflicts is different in the two countries.

Development of traffic conflicts technique for different environments: A comparative study of pedestrian conflicts in Sweden and Jordan

In the past 20 years, several safety measures were taken in an attempt to reduce traffic-related fatalities. Although reduction in deaths was occasionally noticed, the sustainability of that trend has never achieved. This study explores Jordan safety profile trying to explain the traffic safety trend. It examines road traffic safety perception of both public community and road specialist. Main turning points that may have contributed in explaining prevailing traffic safety conditions have been collected. A questionnaire is administered to two distinct groups of the Jordanian society (general public and road specialist) with a total of 167 subjects. The subjects were asked to evaluate the effectiveness of a list of safety measures. Results showed that government took effective but not sustainable measures (mainly enforcement and legislative). Other ineffective measures (administrative and engineering) were taken but they were not target oriented. The main focus of interviewed subjects in order to i...

Road traffic safety perception in Jordan

Laboratory evaluation of elastomer- and plastomer-modified asphalt binders using different grades of asphalt binders and produced asphalt concrete mixes is the subject of this paper. The ev...

Effect of Asphalt Grade and Polymer Type (SBS and EE-2) on Produced PMB and Asphalt Concrete Mix Properties

Jordan's public transport (PT) system is characterized by low quality. Jordanian Citizens are reluctant to use the PT unless they have no other option. This paper aims to examine legislative framework for transport system and its effect on the system. It also aims to analyze factors affecting the sector and make suggestion to develop it. All legislations governing the system since the founding of the Kingdom of Jordan were reviewed including points of weakness in those legislations. Data on PT were collected locally and globally for comparison and were analyzed statistically. Results showed that PT vehicles/1000people in Jordan is low compared to international indicators (0.88 compared with 2.66); PT share is 33%; fare in Jordan is the lowest compared to 12 European cities ($0.47 compared to 2.57). Fares in Jordan cover operation cost compared to nearly half of the cost in 56 cities. User satisfaction index did not exceed 60 percent and it is related to low service spatial coverage. Investment in transport is low; there is a need for innovative funding; engaging private sector, and developing the public transport system and legislation.

/pdf/a-review-of-public-transport-service-in-jordan-challenges-3gdig8gmku.pdf

Lina Shbeeb

Papers

The Use of Polyethylene in Hot Asphalt Mixtures

Development of traffic conflicts technique for different environments: A comparative study of pedestrian conflicts in Sweden and Jordan

Road traffic safety perception in Jordan

Effect of Asphalt Grade and Polymer Type (SBS and EE-2) on Produced PMB and Asphalt Concrete Mix Properties

A Review of Public Transport Service in Jordan: Challenges and Opportunities