Digital Commons Network^™

Environmental Injustice And Racial/Ethnic Heterogeneity In Houston, Texas, Michel G. Loustaunau Garcia

Open Access Theses & Dissertations

This Thesis seeks to contribute to distributive environmental justice (EJ) research by analyzing racial/ethnic and intra-ethnic disparities in potential health risks from exposure to hazardous air pollutants (HAPs) in Harris County, the most populous county in Texas. Previous EJ research in this urban area has not examined intra-ethnic heterogeneity in exposure to air pollutants or attempted to compare social disparities in exposure to air pollution caused by vehicular (mobile) and point (stationary) sources. The goal of this study is to determine how the EJ implications of cancer risks from inhalation exposure to HAPs from mobile and stationary sources differ across …

Geospatial Relationship Of Intelligent Compaction Measurement Values With In-Situ Testing For Quality Assessment Of Geomaterials, Luis Alberto Lemus

Open Access Theses & Dissertations

The implementation of Intelligent Compaction (IC) in the construction of transportation infrastructure as a tool for quality control of compacted geomaterials has attracted the attention of a number of highway agencies. Compaction quality has been conventionally assessed using density, and to a less extent, modulus-based spot measurements at selected locations along the roadway section. While spot measurements do not provide a thorough rendition of the level of compaction of the roadway, IC technology is effective in meeting full coverage requirements. IC roller measurements are accelerometer-based measurements recording machine-ground interaction assumed to be indicative of the stiffness of the compacted geomaterial. …

Practical Models For Interpreting Traffic Speed Deflectometer Data, Setare Ghahri Saremi

Open Access Theses & Dissertations

For more than 30 years, FWDs have been the most viable device for structural pavement evaluation. During the last decade, several moving deflectometers have been introduced, among those, traffic speed deflectometer has been proven as the most utilized device. Since TSD can measure the deflection parameters of pavement at traffic speeds up to 50-60 mph (80-95 kph), it overcomes FWD shortcomings. However, the analysis of the data collected with TSD is in its infancy.

Since TSD measures the vertical component of pavement velocity (a.k.a. deflection velocity), relationships to convert deflection velocities to deflections for further analyses are needed. Computer software …

Comparisons Of Accessibility To Public Transit Stations By Ridesourcing And Its Competitors, David Hoblí­K

Open Access Theses & Dissertations

This Thesis assesses the role of ridesourcing as a mode of first and last mile transport. Review of ridesourcing and taxi business models has been provided as well as a comparative review of laws and regulations regarding ridesourcing and taxi. A potential accessibility gravity based model and logit mode choice model have been applied to compare ridesourcing with other possible modes for first and last mile transport that serve a transit station in Prague, Czech Republic and a transit station in El Paso, Texas. Based on the results, recommendations for ridesourcing companies and local authorities and transportation systems managers are …

Assessment Of Climate Change Impact On Hydraulic Design Procedures Of Bridges, Anjuman Ara Akhter

Open Access Theses & Dissertations

The significant change in climate is evident from the records of increased temperature, changed precipitation pattern, increased frequency of extreme weather events like storms, floods, and so forth. Like other infrastructure highway infrastructures also suffer the consequences of these climate change. Since the hydraulic design of these infrastructures is performed using historical climate data, the designs may not be able to provide services because designs are not considering climate change influence especially in terms of precipitation intensity. This study aims at identifying the most accurate source of climate database that predicts future climate change with less uncertainty and links them …

Utilization Of Digital Image Correlation Technique In Asphalt Testing, Alejandra Escajeda

Open Access Theses & Dissertations

Over 90% of the roads in the United States are paved with hot mix asphalt (HMA). These asphalt pavements include many mix types, such as permeable friction course (PFC), stone mastic asphalt (SMA) and conventional dense graded mixes. The performance of the HMA is an important factor in pavement design programs used by many departments of transportation. The type of HMA selected not only influences the performance of the pavement structure, but also the pavement's life cycle cost. The performance life of an HMA mix is to be studied further with experimental data in order to contribute and expand on …

Assessing Corrosivity Of Galvanized Soil Reinforcements From Electrochemical Tests, Diana Alejandra Cabrera

Open Access Theses & Dissertations

The accurate estimation of the service lives of mechanically stabilized earth (MSE) walls requires a proper evaluation of the corrosion potential through electrochemical test methods. Robust field tests are required to assess the corrosivity of galvanized metal used in MSE walls. To simulate an environment similar to an MSE wall, cylindrical soil specimens about 12 in. (300 mm) in diameter and 10 in. (250 mm) in height were constructed. For every specimen, two instruments were used. The first instrument measured the polarization resistance corrosion tests carried out on galvanized strips and meshes, as well as epoxy-coated rebars. The second instrument …

Optimization For The Allocation Of Funds For Pavement Maintenance In Pavement Management Systems, Armando Ramirez

Open Access Theses & Dissertations

Pavement maintenance and rehabilitation are critical and costly elements for highway agencies. A challenge for transportation agencies is to preserve roadways in an appropriate condition and extend the pavement service life while maintaining the safety and satisfaction of its users, and maximize the benefits obtained by the repair investments. Pavement maintenance programming is increasing in complexity due to limited resources and increments in traffic and population. Management decisions are usually based on personal judgment by pavement managers and sometimes those decisions are not even supported by previous experience. Research shows that optimization methods can produce significant benefits when transportation agencies …

A Sustainable Performance-Based Methodology To Address The Impact Of Climate Changes On The, Oscar Ortega

Open Access Theses & Dissertations

This research focuses to address the effects of climate change on the transportation asset management. Climate change has resulted in increased storms, droughts, flooding, temperatures, and other climate to become more significantly frequent and powerful. As a result, climate change is now affecting the transportation assets around the world. This Thesis is divided into six components: the literature review, development of the framework, development of the methodology, case study, discussion, and conclusions. The literature review will show threats, risks, and performance measures to monitor the climate change impact on transportation infrastructure. The literature review includes transportation asset like bridges, roads, …

A Quality Control Performance-Based Methodology For Pavement Management Systems, Edgar Daniel Rodriguez Velasquez

Open Access Theses & Dissertations

Transportation Asset Management is a decision-making process, which allocates available resources for operating, maintaining, enhancing, and expanding transportation infrastructure while considering its entire life cycle. Transportation infrastructure includes different types of assets and pavements are one of the main assets due to its social, economic, and environmental impacts to society. Transportation agencies implement Pavement Management Systems to support the pavement management process. While implementing and operating a Pavement Management System, one of the costliest procedures is collecting pavement condition data from the field. Good quality for pavement condition data is required to select the right preservation treatments, estimate the associated …