Active traffic management systems aim to relieve recurring and non-recurring congestion by using estimated and predicted traffic conditions to guide trip makers before and after entering the network as well as to design control strategies to improve system performance. With external disruptions and interventions (e.g., weather, special events, and incidents),...
Recently, there has been increasing interest in exploring nano-materials used as an additive to existing concrete materials. With respect to fiber-shaped nanomaterials such as carbon nanofibers (CNF), many studies have shown that mechanical strength properties of cementitious materials can be improved significantly. In this dissertation, the research has focused on...
Precise assessment of long-term aging and deterioration play a major role in life-time predictions of concrete structures. One of the primary challenges in studies of cementitious materials such as concrete comes from the fact that multiple chemical reactions are happening in parallel. Environmental conditions present another challenge as they can...
Reactive Nitrogen (N) and phosphorus (P) pollution is responsible for a vast array of environmental problems, including eutrophication of nutrient limited water bodies, vast dead zones in the ocean margins, and ammonia toxicity to aquatic life. N pollution is also linked to the emission of the potent greenhouse gas nitrous...
Understanding bridge performance and detecting structurally deficient components are of increasing concern to modern infrastructure owners and managers. Concerns over possible effects of increased truck weights led to the opportunity to monitor a highway bridge, regularly subjected to heavy traffic due to logging activities typical of its locale. A weigh-in-motion...
Carbon-based materials, such as graphene and carbon fibers, have good prospects for applications in reinforcements of polymers as advanced structural composites. Hence, the study of the mechanical properties of the constituents and the composites is becoming increasingly popular in both academia and industry.', 'Graphene has been shown to have a...
When constructing buildings with basements in urban areas, the deformation levels during the excavation process must be carefully evaluated to prevent or minimize damage to adjacent structures. Because of uncertainties in predicting ground deformations during the design phase for a project, a robust monitoring program should be included in significant...
This dissertation proposes a new hyperpath-based truck equilibrium assignment model with bidding. Unique from other trucking assignment models that examine assigning trucks for a large fleet of vehicles under a company's control, this model considers the case of many independent but homogeneous carriers that are competing for loads by bidding...
The ongoing generational shift whereby millennials are overtaking baby boomers as the largest generation in the U.S. population, along with the technology-fueled evolution of transportation patterns, offer opportunities for policy makers to leverage changing behavior and build a more sustainable future. Much research has emerged seeking to understand whether the...
The term Connected Vehicle (CV) is broadly used to identify any ‘smart vehicle’ with wireless connectivity to the roadside infrastructure and other vehicles. CVs that can be driven autonomously are called connected autonomous vehicles (CAVs). With real-time communication and data transmission capability, CAVs have the potential to improve the transportation...
Although cementitious construction materials are mainly used in a large scale and in huge quantities, fundamental properties such as strength, ductility, creep, shrinkage, and fracture behavior depend, to a great extent, on structural elements and phenomena which are effective at the micro- and nanoscale. This research involves characterization of the...
While self-consolidating concrete (SCC) may no longer be considered a "new concrete", there are still significant challenges to overcome before there is broader acceptance of SCC. One of these challenges concerns the formwork pressure exerted by SCC. A major advantage of SCC is the accelerated casting process due to the...
Beginning in the 1960s, U.S. federal law required ongoing and systematic planning as a condition of federal transportation funding. An ad-hoc system for forecasting future travel, which has come to be referred to as the "four-step" procedure, quickly became established as the ubiquitous analytic tool for transportation planning. The four-step...
The research reported in this dissertation covers the development of two high-performance concrete materials, Very-High-Strength Concrete (VHSC) and Frangible Concrete, and the philosophy of engineering the microstructure of these materials to produce their specific beneficial traits. The underlying problem addressed was how to optimize their design to maximize their desirable...
Solder joint integrity is recognized as a key issue in the reliability of flip chip and ball grid arrays in integrated circuit packages. Significant reductions in the solder-joint interconnect size results in both the increased volume fraction of brittle intermetallics in the joint and joule heating and electromigration failure due...
Microbiological dating of a crack's age depends upon establishing a viable method of sampling biomass from surfaces. Age is based upon the hypothesis that the amount of biomass on a given crack surface is proportional to the time that has passed since the surface was exposed. Presented herein is the...
Recent work points out the importance of the solid-solid interface in explaining the high photoactivity of mixed phase TiO2 catalysts. The goal of this research was to probe the synthesis-structure-function relationships of the solid-solid interfaces created by the reactive direct current (DC) magnetron sputtering of titanium dioxide. I hypothesize that...
The overall objective of this thesis is to develop a package of high-resolution, non-invasive experimental and numerical approaches to observe in situ pore-scale geometry modification due to colloid deposition, and quantitatively predict its effects on the large-scale transport properties of the porous medium. High-energy synchrotron-based X-ray difference micro-tomography (XDMT) was...
The extensive amount of maintenance expenditures on transportation infrastructure systems and their broad impacts in terms of economic and social development has emerged the interests in maintenance management of transportation infrastructure systems. This dissertation contributes an optimization framework for management of transportation systems that comprise of interdependent facilities.
Existing stochastic,...
Generalized extreme value (GEV) models provide a convenient way to model choice behavior that is consistent with utility maximization theory, but the development of specific new models within the GEV family has been slow, due to the difficulty of ensuring new formulations comply with all the GEV rules. The network...