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2015

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Articles 661 - 690 of 1146

Full-Text Articles in Civil and Environmental Engineering

Analysis Of Air Force Wartime Contracted Construction Project Performance, Ryan M. Hoff Mar 2015

Analysis Of Air Force Wartime Contracted Construction Project Performance, Ryan M. Hoff

Theses and Dissertations

Using a dataset of 25 Afghan wartime projects, two questions were investigated: 1) What factors affect the success of construction projects; and 2) How do project outcomes differ based on the contract type? Current literature suggests that wartime projects may face the same cost and schedule factors as peacetime projects, with some notable additions. Project factors, health and safety compliance, quality of work, technical performance, work productivity, and external environmental factors were tested with contingency tables to determine dependency with schedule or cost performance. External environmental factors, including weather and wartime security, were not predictive of project performance. However, cost …


Pulsed Ultraviolet Light Emitting Diodes For Advanced Oxidation Of Tartrazine, Patrick M. Mudimbi Mar 2015

Pulsed Ultraviolet Light Emitting Diodes For Advanced Oxidation Of Tartrazine, Patrick M. Mudimbi

Theses and Dissertations

A study was conducted to evaluate the advanced oxidation of organic contaminants using pulsed ultraviolet light emitted diode (UV LED). Tartrazine was used as a surrogate organic compound. Low pressure Mercury-based lamps currently used in the treatment of water pose potential health risks if broken and create final disposal issues at the end of their service life. UV LED offers an alternative solution due to its non-toxicity, flexible design, and longer operating life compared to the mercury-based lamps. The apparent first order reaction rate constant for tartrazine degradation increased linearly with increasing duty cycle. At a continuous 100% duty cycle, …


The Fate Of Malathion On Copper And Iron Piping Within A Water Distribution System, Walter R. Lee Mar 2015

The Fate Of Malathion On Copper And Iron Piping Within A Water Distribution System, Walter R. Lee

Theses and Dissertations

Thermogravimetry, the study of mass loss as a function of temperature, has been used for oxidation, decomposition, and solid-state studies. This research used a thermogravimetric analyzer (TGA) coupled with Fourier transform infrared (FT-IR) spectroscopy in the study of copper and iron specimens exposed to malathion. Exposure to the malathion solution created a visible silver coating on copper and graphite-flake particles on iron specimens. Thermogravimetric mass loss curves revealed linear and nonlinear decomposition stages associated with mass loss reactions. Copper specimens exposed to malathion exhibited lower activation energy (Ea) values (2.28 to 4.40 kJ mol-1) than for copper specimens exposed to …


The Effect Of Malathion On The Activity And Performance Of Activated Sludge, Erik G. Rauglas Mar 2015

The Effect Of Malathion On The Activity And Performance Of Activated Sludge, Erik G. Rauglas

Theses and Dissertations

Decontamination activities following a chemical weapons incident may generate significant quantities of contaminated wash water that may enter the wastewater collection system either intentionally or accidentally. This raises concerns about the effect of chemical warfare agents (CWAs) on the operation of a biological wastewater treatment plant. The goal of the study was to evaluate the effect of malathion on the activity and performance of activated sludge. Malathion is an organophosphate (OP) and is considered an environmental surrogate for VX. This study employed respirometry, short term batch tests, and long term exposure experiments to investigate the effects of different concentrations of …


A Probabilistic Assessment Of Failure For Air Force Building Systems, Stephanie L. Alley Mar 2015

A Probabilistic Assessment Of Failure For Air Force Building Systems, Stephanie L. Alley

Theses and Dissertations

Deteriorating and failing federal facilities represent a cost to leaders and organizations as they attempt to manage and maintain these assets. Currently the Air Force employs the BUILDERTM Sustainment Management System to predict the reliability of building components. At different system levels, however, the probabilities of failure are not predicted. The purpose of this research is to provide probabilistic models which predict the probability of failure at the system level of a building s infrastructure hierarchy. This research investigated the plumbing, HVAC, fire protection, and electrical systems. Probabilistic models were created for these systems by using fault trees with …


Test And Evaluation Of Ultrasonic Additive Manufacturing (Uam) For A Large Aircraft Maintenance Shelter (Lams) Baseplate, Daniel H. Gartland Mar 2015

Test And Evaluation Of Ultrasonic Additive Manufacturing (Uam) For A Large Aircraft Maintenance Shelter (Lams) Baseplate, Daniel H. Gartland

Theses and Dissertations

Additive manufacturing is an exciting new manufacturing technology that could have application to Air Force Civil Engineer (CE) operations. This research replicates a Large Area Maintenance Shelter (LAMS) baseplate design for ultrasonic additive manufacturing (UAM). Due to production problems the test section was not built as designed. Instead, a smaller block of material was submitted for evaluation. After the UAM build, ultrasonic inspection was conducted to identify anomalies in the test piece. The results of this proof of concept study indicate that UAM is not yet ready for CE expeditionary applications requiring a high degree of mechanical strength. The machine …


The Impact Of United States Investment For Civil Infrastructure In Developing Countries, Joel N. Hansen Mar 2015

The Impact Of United States Investment For Civil Infrastructure In Developing Countries, Joel N. Hansen

Theses and Dissertations

U.S. foreign assistance is used to support regional interests and to address the economic and social needs of host nation (HN) citizens. Within the Department of Defense (DoD), military exercises implement humanitarian and civic assistance (HCA) activities in developing nations as one method of accomplishing the U.S. foreign assistance objectives. To account for the impact of civil infrastructure projects on HN citizens, this research incorporated survey data collected during a DoD-sponsored exercise in Belize to test the expectancy disconfirmation model of citizen satisfaction and analyze the impact of constructing HCA projects on citizen satisfaction with HN government services. The research …


Effect Of Malathion On The Microbial Ecology Of Activated Sludge, Seth K. Martin Mar 2015

Effect Of Malathion On The Microbial Ecology Of Activated Sludge, Seth K. Martin

Theses and Dissertations

Decontamination activities may cause the release of contaminated washwater into the wastewater that eventually flows into a wastewater treatment facility. This raises concerns about the effect of chemical warfare agents (CWAs) on the microbial consortia that are responsible for cleaning the wastewater. This study investigated the impact of malathion on the microbial ecology of laboratory scale activated sludge communities. The Simpson Reciprocal Index decreased for three bioreactors operated in the absence of malathion, which showed that the microbial assemblage became less diverse during the course of the study. The species identified in the bioreactors belonged to well-known groups of heterotrophic …


Quantiifying Stormwater Runoff Contaminant Mitigation By Bioretention Cells, Patrick J. Walsh Mar 2015

Quantiifying Stormwater Runoff Contaminant Mitigation By Bioretention Cells, Patrick J. Walsh

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

This research study has three objectives, quantify the presence and concentration of selected contaminants in urban stormwater runoff from several urban locations within Lincoln, Nebraska, quantify the effectiveness of two, 10-year old bioretention cells, for reducing concentrations of contaminants in effluent and quantify the effectiveness of six rain gardens.

The primary research sites were two bioretention cells using automated samplers collecting grab samples of stormwater runoff influent and effluent for at least six precipitation events during a two-year period. Additional research sites included samplers for two rainfall, six rain garden, two commercial rooftop, two commercial parking lot, and six residential …


Modeling And Simulation Of Evacuation Plan For Hancock Stadium, Nirmal Neranjan Weerasekara Mar 2015

Modeling And Simulation Of Evacuation Plan For Hancock Stadium, Nirmal Neranjan Weerasekara

Theses and Dissertations

The goal of this study is to use Modeling and Simulation of Evacuation Plan (MSEP) to support management to execute proper evacuation plan in case of emergency at Hancock Stadium in Illinois State University. Analyses of the research literature and evacuation scenarios are used to build a simulation system that will connect a description of emergency and evacuation situation with its context. It shows how an evacuation plan actually functions. The results of the study will help safety managers to understand the current situations of evacuation according to the specific simulation scenarios. The evacuation simulation is categorized according to the …


Risk-Taking Characteristics As Explanatory Variables In Variations Of Fatality Rates In The Southeastern United States, Jodi Anne Godfrey Mar 2015

Risk-Taking Characteristics As Explanatory Variables In Variations Of Fatality Rates In The Southeastern United States, Jodi Anne Godfrey

USF Tampa Graduate Theses and Dissertations

Traffic fatalities accounted for 1.24 million lives lost in 2013 worldwide, and almost 33 thousand of those fatalities were in the U.S. in 2013. The southeastern region of the nation stands out for continuously having higher fatality rates per mile driven than the national average. If one can establish compelling relationships between various factors and fatality rates, then policies and investments can be targeted to increase the safety on the network by focusing on policies that mitigate those factors. In this research effort risk-taking characteristics are explored. These factors have not been as comprehensively reviewed as conventional factors such as …


Integrated Multi-Criteria Signal Timing Design For Sustainable Traffic Operations, Rui Guo Mar 2015

Integrated Multi-Criteria Signal Timing Design For Sustainable Traffic Operations, Rui Guo

USF Tampa Graduate Theses and Dissertations

Traffic signal systems serve as one of the most powerful control tools in improving the efficiency of surface transportation travel. Traffic operations on arterial roads are particularly complex because of traffic interruptions caused by signalized intersections along the corridor. This dissertation research presents a systematic framework of integrated traffic control in an attempt to break down the complexities into several simpler sub-problems such as pattern recognition, environment-mobility relationships and multi-objective optimization for multi-criterial signal timing design.

The overall goal of this dissertation is to develop signal timing plans, including a day plan schedule, cycle length parameters, splits and offsets, which …


National Livestock Policy Of Nepal: Needs And Opportunities, Upendra B. Pradhanang, Soni M. Pradhanang, Arhan Sthapit, Nir Y. Krakauer, Ajay K. Jha, Tarendra Lakhankar Mar 2015

National Livestock Policy Of Nepal: Needs And Opportunities, Upendra B. Pradhanang, Soni M. Pradhanang, Arhan Sthapit, Nir Y. Krakauer, Ajay K. Jha, Tarendra Lakhankar

Publications and Research

This paper describes Nepal’s national livestock policies and considers how they can be improved to help meet the pressing national challenges of economic development, equity, poverty alleviation, gender mainstreaming, inclusion of marginalized and underprivileged communities, and climate vulnerability. Nepal is in the process of transforming its government from a unitary system to a federal democratic structure through the new constitution expected by 2015, offering the opportunity to bring a new set of priorities and stakeholders to policymaking. Nepal’s livestock subsector comes most directly within the purview of the National Agricultural Policy 2004, Agro-Business Policy, 2006 and Agricultural Sectoral Operating Policies …


Integration Of An Energy Balance Snowmelt Model Into An Open Source Modeling Framework, A. Sen Gupta, David G. Tarboton, P. Hummel, M. E. Brown, S. Habib Mar 2015

Integration Of An Energy Balance Snowmelt Model Into An Open Source Modeling Framework, A. Sen Gupta, David G. Tarboton, P. Hummel, M. E. Brown, S. Habib

Civil and Environmental Engineering Faculty Publications

This paper presents a data model for organizing the inputs and outputs of an energy balance snowmelt model (the Utah Energy Balance Model, UEB) that provides a foundation for its integration into the EPA BASINS modeling framework and enables its coupling with other hydrologic models in this system. Having UEB as a BASINS component has facilitated its coupling with the Geospatial Streamflow Forecast Model (GeoSFM) to compute the melting of glaciers and subsequent streamflow in the Himalayas. The data model uses a combination of structured text and network Common Data Form (netCDF) files to represent parameters, geographical, time series, and …


A Unified Approach For Process-Based Hydrologic Modeling: 2. Model Implementation And Case Studies, Martyn P. Clark, Bart Nijssen, Jessica D. Lundquist, Dmitri Kavetski, David E. Rupp, Ross A. Woods, Jim E. Freer, Ethan D. Gutmann, Andrew W. Wood, David J. Gochis, Roy M. Rasmussen, David G. Tarboton, Vinod Mahat, Gerald N. Flerchinger, Danny G. Marks Mar 2015

A Unified Approach For Process-Based Hydrologic Modeling: 2. Model Implementation And Case Studies, Martyn P. Clark, Bart Nijssen, Jessica D. Lundquist, Dmitri Kavetski, David E. Rupp, Ross A. Woods, Jim E. Freer, Ethan D. Gutmann, Andrew W. Wood, David J. Gochis, Roy M. Rasmussen, David G. Tarboton, Vinod Mahat, Gerald N. Flerchinger, Danny G. Marks

Civil and Environmental Engineering Faculty Publications

This work advances a unified approach to process-based hydrologic modeling, which we term the “Structure for Unifying Multiple Modeling Alternatives (SUMMA).” The modeling framework, introduced in the companion paper, uses a general set of conservation equations with flexibility in the choice of process parameterizations (closure relationships) and spatial architecture. This second paper specifies the model equations and their spatial approximations, describes the hydrologic and biophysical process parameterizations currently supported within the framework, and illustrates how the framework can be used in conjunction with multivariate observations to identify model improvements and future research and data needs. The case studies illustrate the …


Solids Accumulation Rates Of Latrines At Rural Schools In Nimba County, Liberia, Caraline M. Murphy Mar 2015

Solids Accumulation Rates Of Latrines At Rural Schools In Nimba County, Liberia, Caraline M. Murphy

USF Tampa Graduate Theses and Dissertations

Access to appropriate sanitation facilities as well as access to clean drinking water are considered fundamental human rights (Carr, 2001; Bjorklund & Sjodin, 2010), yet roughly 2.5 billion people on the planet lack access to an improved form of sanitation (WHO/UNICEF, 2014). Additionally, many entities responsible for emergency excreta management and sanitation management design guidelines, specifically solids accumulation rates in latrine pits, use rates that are 30-60 years old and may be established from dated knowledge on diet and lifestyle trends (Franceys et al., 1992; Harvey et al., 2002; Harvey, 2007). Using solids accumulation rates that are dated as well …


Event-Based Hydrologic Model Calibration Using Nexrad In A Data-Poor Region Of Southern New Jersey, Christopher Siegel Mar 2015

Event-Based Hydrologic Model Calibration Using Nexrad In A Data-Poor Region Of Southern New Jersey, Christopher Siegel

Theses and Dissertations

Proper calibration of hydrologic models requires both reliable observed stream flow and precipitation data. Southern New Jersey has a notable lack of observed precipitation data, in particular, at the event scale; therefore model calibration represents a significant challenge. From a design standpoint this has not been a major concern as hydrologic models have been driven using design storms and are not calibrated. However, the need for research and impact analyses in the face of climate change (changes in extreme precipitation and sea-level rise in particular) and expected population growth in the region requires calibrated models, and reliable observed precipitation data …


Structural Integrity Of Conventional And Modified Railroad Bearing Adapters For Onboard Monitoring, Joseph Montalvo, Alexis Trevino, Arturo A. Fuentes, Constantine Tarawneh Mar 2015

Structural Integrity Of Conventional And Modified Railroad Bearing Adapters For Onboard Monitoring, Joseph Montalvo, Alexis Trevino, Arturo A. Fuentes, Constantine Tarawneh

Mechanical Engineering Faculty Publications

This paper presents a detailed study of the structural integrity of conventional and modified railroad bearing adapters for onboard monitoring applications. Freight railcars rely heavily on weigh bridges and stations to determine cargo load. As a consequence, most load measurements are limited to certain physical railroad locations. This limitation provided an opportunity for an optimized sensor that could potentially deliver significant insight on bearing condition monitoring as well as load information. Bearing adapter modifications (e.g. cut outs) were necessary to house the sensor and, thus, it is imperative to determine the reliability of the modified railroad bearing adapter, which will …


Particulate-Matter Emission Estimates From Agricultural Spring-Tillage Operations Using Lidar And Inverse Modeling, Kori D. Moore, Michael D. Wojcik, Randy S. Martin, Christian C. Marchant, D. S. Jones, W. J. Bradford, G. E. Bingham, R L. Pfeiffer, J. H. Prueger, J. L. Hatfield Mar 2015

Particulate-Matter Emission Estimates From Agricultural Spring-Tillage Operations Using Lidar And Inverse Modeling, Kori D. Moore, Michael D. Wojcik, Randy S. Martin, Christian C. Marchant, D. S. Jones, W. J. Bradford, G. E. Bingham, R L. Pfeiffer, J. H. Prueger, J. L. Hatfield

Civil and Environmental Engineering Faculty Publications

Particulate-matter (PM) emissions from a typical spring agricultural tillage sequence and a strip–till conservation tillage sequence in California’s San Joaquin Valley were estimated to calculate the emissions control efficiency (ηη) of the strip–till conservation management practice (CMP). Filter-based PM samplers, PM-calibrated optical particle counters (OPCs), and a PM-calibrated light detection and ranging (LIDAR) system were used to monitored upwind and downwind PM concentrations during May and June 2008. Emission rates were estimated through inverse modeling coupled with the filter and OPC measurements and through applying a mass balance to the PM concentrations derived from LIDAR data. Sampling irregularities and errors …


Pavement Underdrain To Achieve Longer Life Pavement Structure, Tommy E. Nantung Mar 2015

Pavement Underdrain To Achieve Longer Life Pavement Structure, Tommy E. Nantung

Purdue Road School

Drainage as the key to pavement performance has been suggested since the early design of modern pavement structures. In fact, the three parameters for pavement performance are drainage, drainage and drainage. Drainage is so important to the performance of pavement that many state DOTs mandate a pavement underdrain system for routes with medium to high truck traffic. In the current evolution of pavement underdrain design, the speed of water removal from the soil foundation is the key issue. In a recent field investigation, some pavement sections with an underdrain system are not immune to pavement structural deterioration. It was determined …


Indygo Downtown Transit Center - Transforming Indianapolis, Ben Smith, Steve Robinson, Joe Fischer Mar 2015

Indygo Downtown Transit Center - Transforming Indianapolis, Ben Smith, Steve Robinson, Joe Fischer

Purdue Road School

The new IndyGo Downtown Transit Center will transform transit in downtown Indianapolis and offers lessons in transit planning, traffic planning, intermodal connectivity, public engagement, and pedestrian access. This presentation will give an overview of the facility and then focus on attributes of the facility and of the design process that might offer useful lessons to other transit projects, including those of a smaller scale


Pavement Rehabilitation Options In Indiana, David Holtz, Tommy E. Nantung, Lisa A. Egler-Kellems Mar 2015

Pavement Rehabilitation Options In Indiana, David Holtz, Tommy E. Nantung, Lisa A. Egler-Kellems

Purdue Road School

Many pavement rehabilitation options are now available to maintain the function and structure of a pavement section, and pavement engineers can choose an option that is suitable for the existing pavement condition. Many agencies today use traditional pavement rehabilitation techniques such as patching, overlay, and mill and fill. Recent developments in materials and construction have made available new rehabilitation options that are not only cost effective but also increase the use of recycled materials. This presentation will feature hot-in-place recycling, cold-in-place recycling, and full-depth reclamation techniques used successfully with recently rehabilitated pavement sections in Indiana.


Railroad Quiet Zones, Glen T. Campbell, Mary Cripe Mar 2015

Railroad Quiet Zones, Glen T. Campbell, Mary Cripe

Purdue Road School

Speaker(s): Mary Cripe, P.E., City of Goshen Engineering Department

Glen Campbell, P.E., Patrick Engineering

Track: Multi-Modal Transportation

Submission ID #: 119

Presentation Duration: 50 Minutes

Presentation Title: Railroad Quiet Zones

Abstract: In 2005, the Federal Railroad Administration (FRA) provided communities with the opportunity to reduce locomotive horn noise without compromising public safety. The proposed Marion Branch Quiet Zone, located in Goshen, Indiana, will not only improve public safety, it will also enhance the quality of life and raise home values for adjacent residents.

This intricate process involves creative problem-solving and knowledge of the multiple parties involved. It will take a …


Social Media For Local Government Agencies, Sam Taylor Mar 2015

Social Media For Local Government Agencies, Sam Taylor

Purdue Road School

With more and more people communicating online, many local agencies are making the shift to include social media as part of their outreach efforts. This session will include a breakdown of the most common social me­dia networks used by local agencies, ideas for useful and engaging content, and a discussion of best practices for social media communications. Examples will be drawn from other local agency success stories, including local agencies within Indiana.


Simplified Pavement Design For Lpas: Introduction To Pavexpress, Dudley Bonte Mar 2015

Simplified Pavement Design For Lpas: Introduction To Pavexpress, Dudley Bonte

Purdue Road School

Simplified Pavement Design for LPA's; An introduction to and use of PaveXpress, a simplified, free, web-based pavement design scoping tool for roadway and parking lot pavements. The system was developed by Pavia Systems in partnership with the National Asphalt Pavement Association. PaveXpress creates technical sound pavement structural designs for flexible and rigid pavements based on widely accepted industry standards from the Association of State Highway Officials (AASHTO). The simplified pavement design system is based on empirical equation from the 1993 AASHTO Guide for the Design of Pavement Structures. PaveXpress is intended for use by local agencies, engineers and consultants …


Gis Tools For Hydrology And Hydraulics, David D. Finley Mar 2015

Gis Tools For Hydrology And Hydraulics, David D. Finley

Purdue Road School

GIS information sources used by the Office of Hydraulics to improve the accuracy and efficiency hydrologic computations will be presented. A variety of information sources will be discussed with an emphasis on DEM data obtained from Indiana's recent state-wide mapping initiative. Sources and limitations of the data will be discussed, and techniques for utilizing this data will be introduced.


Assessment Of Surface Soil Moisture Using High-Resolution Multi-Spectral Imagery And Artificial Neural Networks, Leila Hassan-Esfahani, Alfonso F. Torres-Rua, Austin M. Jensen, Mac Mckee Mar 2015

Assessment Of Surface Soil Moisture Using High-Resolution Multi-Spectral Imagery And Artificial Neural Networks, Leila Hassan-Esfahani, Alfonso F. Torres-Rua, Austin M. Jensen, Mac Mckee

Civil and Environmental Engineering Faculty Publications

Many crop production management decisions can be informed using data from high-resolution aerial images that provide information about crop health as influenced by soil fertility and moisture. Surface soil moisture is a key component of soil water balance, which addresses water and energy exchanges at the surface/atmosphere interface; however, high-resolution remotely sensed data is rarely used to acquire soil moisture values. In this study, an artificial neural network (ANN) model was developed to quantify the effectiveness of using spectral images to estimate surface soil moisture. The model produces acceptable estimations of surface soil moisture (root mean square error (RMSE) = …


Spatial And Temporal Variability Of Rainfall In The Gandaki River Basin Of Nepal Himalaya, Jeeban Panthi, Piyush Dahal, Madan Lall Shrestha, Suman Aryal, Nir Y. Krakauer, Soni M. Pradhanang, Tarendra Lakhankar, Ajay K. Jha, Mohan Sharma, Ramchandra Karki Mar 2015

Spatial And Temporal Variability Of Rainfall In The Gandaki River Basin Of Nepal Himalaya, Jeeban Panthi, Piyush Dahal, Madan Lall Shrestha, Suman Aryal, Nir Y. Krakauer, Soni M. Pradhanang, Tarendra Lakhankar, Ajay K. Jha, Mohan Sharma, Ramchandra Karki

Publications and Research

Landslides, floods, and droughts are recurring natural disasters in Nepal related to too much or too little water. The summer monsoon contributes more than 80% of annual rainfall, and rainfall spatial and inter-annual variation is very high. The Gandaki River, one of the three major rivers of Nepal and one of the major tributaries of the Ganges River, covers all agro-ecological zones in the central part of Nepal. Time series tests were applied for different agro-ecological zones of the Gandaki River Basin (GRB) for rainfall trends of four seasons (pre-monsoon, monsoon, post-monsoon and winter) from 1981 to 2012. The non-parametric …


Railroad Capacity Tools And Methodologies In The U.S. And Europe, Hamed Pouryousef, Pasi Lautala, Thomas White Mar 2015

Railroad Capacity Tools And Methodologies In The U.S. And Europe, Hamed Pouryousef, Pasi Lautala, Thomas White

Michigan Tech Publications, Part 1

A growing demand for passenger and freight transportation, combined with limited capital to expand the United States (U.S.) rail infrastructure, is creating pressure for a more efficient use of the current line capacity. This is further exacerbated by the fact that most passenger rail services operate on corridors that are shared with freight traffic. A capacity analysis is one alternative to address the situation and there are various approaches, tools, and methodologies available for application. As the U.S. continues to develop higher speed passenger services with similar characteristics to those in European shared-use lines, understanding the common methods and tools …


Verification Of The Dissipated Energy Based Fatigue Model Using Field Data, Thomas Redles Mar 2015

Verification Of The Dissipated Energy Based Fatigue Model Using Field Data, Thomas Redles

Theses and Dissertations

Damage can be limited to the top layer in perpetual pavements through the use of a very thick surface layer or a binder-rich intermediate layer. To achieve this goal, tensile strains at the bottom of the top hot-mix asphalt (HMA) layer must be limited to below a certain value known as the fatigue endurance limit (FEL). In this thesis, a method for estimating the allowable strain in the asphalt layers of flexible airfield pavements is proposed based on the concept that HMA fatigue failure is associated with a significant reduction in HMA layer modulus, usually taken as 50 percent. Falling …