The Effects of Salt on Rheological Properties of Asphalt after Long-Term Aging
Limited studies in recent years have shown that asphalt pavement subject to seawater in coastal regions or deicing salt in cold regions may be seriously damaged after being soaked in saline water for a long time. However, there is limited research into the influence of salt on rheological properties of asphalt after long-term aging. In this study, rheological properties of unmodified and polymer-modified asphalt after long-term aging were tested after being soaked in different concentrations of salt (0.3%~5%) for different durations (1 day~30 days). Orthogonal array based on the Taguchi method was used for experimental design. The frequency sweep tests were performed on the specimens of aged asphalt after being soaked for complex modulus and phase angle master curves and ultimate fatigue temperature. BBR tests were performed for stiffness. The test results indicate that saline water appears to reduce low temperature properties and fatigue resistance properties and improved high temperature properties of aged asphalt, and it also affects the sensitivity of complex modulus and phase angles at low frequencies.
Evaluation of Open-graded Friction Course Mixtures Containing Cellulose Fibers and Styrene Butadiene Rubber Polymer
Open-graded friction course (OGFC) or porous mixtures consist of an open gradation, mostly of coarse size aggregate with little fines. The benefits of an OGFC mixture are typically increased surface permeability, noise reduction, and enhanced surface friction, especially in wet weather. This paper presents the results of a study investigating four different OGFC mixes containing no additives, cellulose fibers, styrene butadiene rubber (SBR) polymer, and a combination of both fibers and SBR polymer. Mix designs were performed according to the design procedure proposed by the National Center of Asphalt Technology for a range of 4.5–6.5% asphalt content. The mixture containing fibers and SBR polymer was selected as an acceptable mix design with an optimum asphalt content of 6.5%. The moisture susceptibility of the selected mix at optimum asphalt content was evaluated. Results were compared with that for a dense mix.
Factors Likely to Influence Tort Litigation in the European Union
As the European Union moves towards harmonization in a variety of business, political, and regulatory settings, an opportunity exists to influence the form of tort liability found in these nations. The opportunity should not be missed, with rising concern that U.S. influences will set into motion costly litigiousness, particularly as EU member nations pull back on the level of social programmes available to cover costs typically included in tort claims. To assist policymakers in their deliberations about European Union tort directives, this paper provides discussion of the frequently cited key differences between the U.S. tort systems and what is found in most EU member nations. The discussion is focused on available evidence regarding the influences of these differences as well as important areas of future research. The most important areas seem to be (1) the need to enforce European Law when no defined regulatory body exists for this purpose; (2) the connection between government social programmes and the need for tort liability compensation; (3) and the influence of rules governing payment of legal costs and lawyer fees.