Chapters authored
Analytical Assessment of Effective Maintenance Operations on At-Grade Unsignalized Intersections
This chapter describes a methodological structure to support and improve the decision-making process for redesigning the geometric configurations of substandard sites and thus reduce crash risk factors on at-grade three-leg and four-leg intersections with stop-control on minor roads and single-lane roundabouts belonging to a two-lane rural road network located in Southern Italy. Starting from an initial evaluation of the risk level at each investigated site and adopting a procedure developed by the Italian National Research Council based on an estimated crash rate level, a more precise hierarchy of intersections with “black” rankings was developed. In addition, new geometric configurations for the most hazardous sites were suggested based on a statistical comparison in terms of safety and Level of Service (LoS). The effectiveness of the strategies was validated by computing the expected LoS and safety by adopting an empirical Bayesian analysis and performance functions centered on a revised Highway Safety Manual procedure reflecting the context of the study.
Part of the book: Transportation Systems Analysis and Assessment
Road Asphalt Pavements Made by Bottom Ashes from Waste-to-Energy Plant as a Filler
Not all waste is completely burned by waste-to-energy plants. About 73% of it is bottom ashes (BA). Sustainable reuse of the BA is to reprocess them into the production chain of the asphalt mixtures for road pavements. This research deals with an experimental investigation of the mechanical performance of hot and cold asphalt mastics made with the BA filler versus the traditional ones containing limestone powder (LP). First, environmental compatibility tests were carried out and then a rheological analysis, applying viscosity, frequency sweep, and multiple stress creep and recovery tests, was performed to check the feasibility of using the BA as a filler for asphalt-based materials. Looking at the main results, the ecotoxicological tests in terms of EC50 for toxicity on Daphnia and EC50 for algal growth inhibition confirmed the usability of all the mastics from an environmental point of view. The rheological results showed higher G* values for cold asphalt mastics made up with the BA compared to the corresponding solutions made with the LP. Additionally, it was also observed that the mastics containing BA returned a 90% decrease in non-recoverable creep compliance at test temperatures over 40°C compared to the corresponding mastics made with the LP.
Part of the book: Asphalt Materials - Recent Developments and New Perspective [Working title]