Civil Engineering Commons^™

A Stochastic Approach For Pavement Condition Projections And Budget Needs For The Mtc Pavement Management System, Rafael Arturo Ramirez Flores

Open Access Theses & Dissertations

Pavement management decision-making is the most important task for officials in transportation agencies, who develop maintenance and rehabilitation programs. Information about historical pavement network performance is needed for decision-making; pavement management systems (PMS) provide means to organize road network data to improve the pavement network condition. PMS have prediction performance models to forecast the future condition of the pavement networks with information required for decision-making; these models can be deterministic or probabilistic. Pavement performance deterministic models are commonly used in PMS, but they do not consider the uncertainty in forecasting pavement performance. Pavement performance depends on many random factors like …

Comparison Of Bicycle Transportation Systems In El Paso And Prague, Jose C Hernandez

Open Access Theses & Dissertations

Bicycle transportation infrastructure has an important role in bicycle transportation mode. Every year there are hundreds of accidents where bicyclist are involve, because there is not a good infrastructure for bicycles in the roads bicyclists have a potential risk. One of the main purposes is maintain the bicyclistsâ?? safety in the roads to attract more people to use this eco-friendly transportation mode. The goal of this Thesis is compare the bicycle infrastructure in two different countries, United States and Czech Republic. The history and the main terminology are described in firsts chapters. Based on law and regulations, design criteria and …

Alternative Fatigue Cracking Resistance Assessment Criteria Of Asphalt Mixtures With Overlay Tester, Alejandro Miramontes

Open Access Theses & Dissertations

The accumulation of damage due to cracking of hot mix asphalt (HMA) layers under repeated loading along with the climatic effects is known as fatigue cracking. The Overlay Tester (OT) has been implemented or considered by several highway agencies as an index to evaluate the cracking susceptibility and resistance to cracking of asphalt mixtures in the laboratory. The performance indicator used to measure the quality of the HMA mixes is the number of cycles that a specimen may resist during the test until the crack appears and fully propagates to the top of the specimen. The repeatability of the number …

A Methodology For Use Of Digital Image Correlation For Hot Mix Asphalt Testing, Estefany Ramos

Open Access Theses & Dissertations

Digital Image Correlation (DIC) is a relatively new technology which aids in the measurement of material properties without the need for installation of sensors. DIC is a noncontact measuring technique that requires the specimen to be marked with a random speckled pattern and to be photographed during the test. The photographs are then post-processed based on the location of the pattern throughout the test. DIC can aid in calculating properties that would otherwise be too difficult even with other measuring instruments.

The objective of this Thesis is to discuss the methodology and validate the use of DIC in different hot …

A Rapid Approach For Considering Nonlinear Response Of Flexible Pavements Under Fwd And Estimation Of Remaining Lives Of Pavements, Shahabaldin Shirazi

Open Access Theses & Dissertations

Most mechanistic empirical pavement analyses are based on the layered elastic models where the stress sensitivity of geomaterials and their nonlinearity are either ignored or accounted for indirectly. Advanced numerical models, such as finite element models, are required to consider the nonlinear nature of the geomaterials. Existing pavements are often tested with the Falling Weight Deflectometer (FWD) to estimate the input moduli to the layered elastic models in order to estimate remaining life and structural capacity of pavements. It has been more than 30 years that FWD tests are being performed to measure structural adequacy of pavements. Backcalculation is the …

Evaluation Of Point Of Use Drinking Water Treatment Systems For Colonias In The Southwest United States, Isaac Campos Flores

Open Access Theses & Dissertations

Clean drinking water is often taken for granted in first world countries, such as the United States. However, thousands of colonias residents (settlements in the Southwest US that lack access to basic infrastructure) still lack access to clean drinking water. Such is the case in the Paso Del Norte Region. In Doña Ana County, NM, and El Paso County, TX, colonia residents typically rely on shallow domestic wells and hauled water, respectively. However, both water sources can pose health concerns from elevated total dissolved solids and microbiological contamination. With connection to centralized water treatment and distribution still years away, colonias …

Moisture Susceptibility Of Dense Graded Asphalt Concrete Using Cyclic Moistue Induced Stress Tester, Sarvesh Dip Dhakal

Open Access Theses & Dissertations

Moisture damage in asphalt concrete causes loss in mechanical properties of asphalt material due to the presence of moisture in its microstructures in a liquid or a vapor state. Some of the common types of distress observed in asphalt pavements due to moisture damage are stripping (separation of asphalt binder and aggregate), raveling (dislodgement of aggregate particles in asphalt mixture from surface), and hydraulic scour (a process that occurs on a saturated surface by which the pavement material is eroded due to dynamic action of tires in the presence of water). This Thesis focuses on the research on the effects …

Reliability And Sensitivity Analysis For Micro-Meteoroids And Orbital Debris Protection Models Using First-Order Reliability Methods (Form)., Levi Pereda

Open Access Theses & Dissertations

Abstract This Thesis provides a probabilistic assessment of the micro-meteoroids and orbital debris (MMOD) impact protection structures. The assessment is based on first-order reliability methods that use Ballistic Limit equations traditionally used by NASA for the design of shields. The research demonstrates how the structural reliability methods can be implemented into the aeronautics and astronautics field. NASA is continuously developing new techniques that allow the consideration of the uncertainty that exists in the design of their space structures. Nevertheless, some of their design approaches are still deterministic. For example MMOD ballistic limit equations used for the design of the MMOD …

Recovery Of Nutrient Nitrogen From Municipal Wastewater Residuals By Gas Membrane Separation, Evelyn Rios

Open Access Theses & Dissertations

There are relatively high amounts of ammonia returned to the headworks of a municipal wastewater plant that are extracted from the dewatering process. This ammonia load contributes to a significant oxygen demand in the secondary treatment, requiring greater air blower energy costs. This goal of this research was to evaluate the feasibility of the recovery of an ammonium sulfate product from belt press filtrate. The objectives of this research were to: (1) analyze wastewater treatment average monthly data flows and constituents with respect to ammonia nitrification, (2) the evaluate the technical performance of a two sage gas-separation membrane for recovering …

Performance Life Of Various Hot Mix Asphalt Mixtures In Texas, Danniel David Rodriguez

Open Access Theses & Dissertations

Typically, pavement engineers in subjectively estimate the service lives of various hot-mix asphalt (HMA) mixtures as part of the life-cycle cost analysis considering the staged design and rehabilitation of flexible pavements. This study proposes the performance lives for the various dense-graded (conventional) mixtures, stone-matrix asphalts (SMA), permeable friction courses (PFC), performance design mixtures and other mixtures placed in Texas. A necessary and significant aspect of the approach involved data mining and merging several pavement management databases (Letting Database, DCIS and PMIS) to obtain mixture longevity data along with historical PMIS information. The product of the linking process resulted in the …

Accuracy And Precision Evaluation Of Traffic Speed Pavement Deflection Devices, Jorge Velarde

Open Access Theses & Dissertations

Pavement structural adequacy is considered an important aspect of the pavement management activities and can be incorporated by using surface pavement deflections. Continuous deflection technology, which has been around for several years, can potentially supplant single point deflection measurements provided by the Falling Weight Deflectometer (FWD). Previous studies have evaluated the traffic speed deflection devices (TSDD) accuracy and precision by comparing their results with FWD measurements. Although appropriate correlations and indices to compensate for the differences in load have been made, a direct comparison under the same loading conditions has not been reported in the literature.

The goal of this …