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Articles 13951 - 13980 of 39837

Full-Text Articles in Civil and Environmental Engineering

Accommodating Exogenous Variable And Decision Rule Heterogeneity In Discrete Choice Models: Application To Bicyclist Route Choice, Bibhas Dey Jan 2018

Accommodating Exogenous Variable And Decision Rule Heterogeneity In Discrete Choice Models: Application To Bicyclist Route Choice, Bibhas Dey

Electronic Theses and Dissertations

The thesis contributes to our understanding of incorporating heterogeneity in discrete choice models with respect to exogenous variables and decision rules. Specifically, we evaluate latent segmentation based mixed models that allow for segmenting population based on decision rules while also incorporating unobserved heterogeneity within the segment level decision rule models. In our analysis, we choose to consider the random utility framework along with random regret minimization approach. Further, instead of assuming the number of segments (as 2), we conduct an exhaustive exploration with multiple segments across the two decision rules. Within each segment we also allow for unobserved heterogeneity. The …

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Understanding Crisis Communication And Mobility Resilience During Disasters From Social Media, Kamol Roy Jan 2018

Understanding Crisis Communication And Mobility Resilience During Disasters From Social Media, Kamol Roy

Electronic Theses and Dissertations

Rapid communication during extreme events is one of the critical aspects of successful disaster management strategies. Due to their ubiquitous nature, social media platforms offer a unique opportunity for crisis communication. Moreover, social media usage on GPS enabled devices such as smartphones allow us to collect human movement data which can help understanding mobility during a disaster. This study leverages social media (Twitter) data to understand the effectiveness of social media-based communication and the resilience of human mobility during a disaster. This thesis has two major contributions. First, about 52.5 million tweets related to hurricane Sandy are analyzed to assess …

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Assessing The Impact Of Multi-Variate Steering-Rate Vehicle Control On Driver Performance In A Simulation Framework, Michael Xynidis Jan 2018

Assessing The Impact Of Multi-Variate Steering-Rate Vehicle Control On Driver Performance In A Simulation Framework, Michael Xynidis

Electronic Theses and Dissertations

When a driver turns a steering-wheel, he or she normally expects the vehicle's steering system to communicate an equivalent amount of signal to the road-wheels. This relationship is linear and occurs regardless of the steering-wheel's position within its rotational travel. The linear steering paradigm in passenger vehicles has gone largely unchanged since mass production of passenger vehicles began in 1901. However, as more electronically-controlled steering systems appear in conjunction with development of autonomous steering functions in vehicles, an opportunity to advance the existing steering paradigms arises. The following framework takes a human-factors approach toward examining and evaluating alternative steering systems …

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Development And Application Of An Optimization Approach For Cost-Effective Deployment Of Advanced Wrong-Way Driving Countermeasures, Adrian Sandt Jan 2018

Development And Application Of An Optimization Approach For Cost-Effective Deployment Of Advanced Wrong-Way Driving Countermeasures, Adrian Sandt

Electronic Theses and Dissertations

Wrong-way driving (WWD) is a dangerous behavior, especially on high-speed divided highways. The nature of WWD crashes makes it difficult for agencies to combat them effectively. Advanced WWD countermeasures equipped with flashing lights, detection devices, and cameras can significantly reduce WWD. However, these countermeasures' high costs mean that agencies often cannot deploy them at all exit ramps. To help agencies identify the most cost-effective deployment locations for advanced WWD countermeasures, an innovative WWD countermeasure optimization approach was developed. This approach consists of a WWD hotspots model and a WWD countermeasures optimization algorithm. The WWD hotspots model uses non-crash WWD events, …

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A Holistic Analysis Of The Long-Term Challenges & Potential Benefits Of The Green Roof, Solar Pv Roofing, And Gripv Roofing Markets In Orlando, Florida, Carolina Kelly Jan 2018

A Holistic Analysis Of The Long-Term Challenges & Potential Benefits Of The Green Roof, Solar Pv Roofing, And Gripv Roofing Markets In Orlando, Florida, Carolina Kelly

Electronic Theses and Dissertations

Green roofs and roof-mounted solar PV arrays have a wide range of environmental and economic benefits, including significantly longer roof lifetimes, reductions in urban runoff, mitigation of the urban heat island (UHI) effect, reduced electricity demand and energy dependence, and/or reduced emissions of greenhouse gases (GHGs) and other harmful pollutants from the electricity generation sector. Consequently, green roofs and solar panels have both become increasingly popular worldwide, and promising new research has emerged for their potential combination in Green Roof Integrated Photovoltaic (GRIPV) roofing applications. However, due to policy resistance, these alternatives still have marginal market shares in the U.S., …

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Seismic Response Of Moment Resisting Frames Coupled With Rocking Walls, Mehrdad Aghagholizadeh Jan 2018

Seismic Response Of Moment Resisting Frames Coupled With Rocking Walls, Mehrdad Aghagholizadeh

Electronic Theses and Dissertations

This study investigates the inelastic response of yielding structures coupled with rocking walls. This topic is of major significance in the design of tall moment-resisting buildings, since during recent major earthquakes several tall, moment-resisting frames that had been designed in an accordance to the existing seismic code provisions, exhibited a weak-story failure. Utilization of this structural system can help reducing maximum story drifts, prevents weak story failure and minimize residual deformation of the structure. This study first examines different configurations of both stepping rocking walls and pinned rocking walls that have been reported in the literature. Next, effect of additional …

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Seepage And Stability Analysis Of The Earth Dams Under Drawdown Conditions By Using The Finite Element Method, Salama Al-Labban Jan 2018

Seepage And Stability Analysis Of The Earth Dams Under Drawdown Conditions By Using The Finite Element Method, Salama Al-Labban

Electronic Theses and Dissertations

One of the major concerns in the behavior of an earth dam is the change in the exit gradient and the impact on the slope stability under drawdown conditions. Drawdown can cause increased seepage forces on the upstream slope which may result in the movement of soil particles in the flow direction and cause erosion problems. In this research, a numerical approach, based on the finite element method (FEM) is used to analyze the seepage through the dam and its foundation to study exit gradients and slope stability under both steady-state and transient conditions. The results show that a central …

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Development Of Soil Compressibility Prediction Models, Scott Kirts Jan 2018

Development Of Soil Compressibility Prediction Models, Scott Kirts

Electronic Theses and Dissertations

The magnitude of the overall settlement depends on several variables such as the Compression Index, Cc, and Recompression Index, Cr, which are determined by a consolidation test; however, the test is time consuming and labor intensive. Correlations have been developed to approximate these compressibility indexes. In this study, a data driven approach has been employed in order to estimate Cc and Cr. Support Vector Machines classification is used to determine the number of distinct models to be developed. The statistical models are built through a forward selection stepwise regression procedure. Ten variables were used, including the moisture content (w), initial …

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The Acquisition Of Knowledge And Expertise In Construction: Understanding Construction Professionals, Lloyd Scott, Sittimont Kanjanabootra Jan 2018

The Acquisition Of Knowledge And Expertise In Construction: Understanding Construction Professionals, Lloyd Scott, Sittimont Kanjanabootra

Conference papers

Education programs these days especially in Construction Management have been designed and updated to response to market and stakeholder needs. However, there still exists a need for educators to understand how construction practitioners develop their expertise. Understanding the development of expertise is essential for providers of university education and training to enable them to develop programs to establish on which new professionals can better develop their appropriate expertise. This paper builds on earlier research and further explores how expertise develops in construction professionals. It also explores the similarities and differences in development of that expertise in construction practitioners from the …

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Vegetation Mapping Of A Coastal Dune Complex Using Multispectral Imagery Acquired From An Unmanned Aerial System, C. Suo, Eugene Mcgovern, Alan Gilmer Jan 2018

Vegetation Mapping Of A Coastal Dune Complex Using Multispectral Imagery Acquired From An Unmanned Aerial System, C. Suo, Eugene Mcgovern, Alan Gilmer

Conference Papers

Vegetation mapping, identifying the distribution of plant species, is important for analysing vegetation dynamics, quantifying spatial patterns of vegetation evolution, analysing the effects of environment changes on vegetation, and predicting spatial patterns of species diversity. Such analysis can contribute to the development of targeted land management actions that maintain biodiversity and ecological functions. This paper represents a methodology for 3D vegetation mapping of a coastal dune complex using a multispectral camera mounted on an Unmanned Aerial System (UAS) with particular reference to the Buckroney dune complex in Co. Wicklow, Ireland. UAS, also known as Unmanned Aerial Vehicles (UAV’s) or drones, …

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A Pseudo-Microsimulation Approach For Modelling Congested Traffic Loading On Long-Span Bridges, Colm Carey, Colin Caprani, Bernard Enright Jan 2018

A Pseudo-Microsimulation Approach For Modelling Congested Traffic Loading On Long-Span Bridges, Colm Carey, Colin Caprani, Bernard Enright

Articles

This paper investigates congested traffic loading on long-span bridges through the use of traffic microsimulation. Six months of Weigh-In-Motion free-flow traffic data (including cars) are used as input for the microsimulation of congested traffic. Key parameters that affect traffic loading are identified in the output of the microsimulation, and these parameters form the basis for a more computationally efficient ‘pseudo-microsimulation of congested traffic’ (PMCT) model. This PMCT model is shown to replicate the traffic loading from full microsimulation accurately and allows long-run simulations, equivalent to 1000 years of congested traffic, to be performed with an acceptably short duration. This reduces …

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Calcium Alginate Capsules Encapsulating Rejuvenator As Healing System For Asphalt Mastic, S. Xu, Amir Tabakovic, X. Liu, E. Schlangen Jan 2018

Calcium Alginate Capsules Encapsulating Rejuvenator As Healing System For Asphalt Mastic, S. Xu, Amir Tabakovic, X. Liu, E. Schlangen

Research and Innovation - Articles

Researchers have demonstrated that the rejuvenator encapsulation method is a promising autonomic self-healing approach for asphalt pavements, where by the self-healing system improves the healing capacity of an asphalt pavement mix. However, potentially high environmental risk via leaching of hazardous chemicals such as melamine formaldehyde renders the technology unsuitable for widespread use in road design. This paper explores the potential for the use of more environmentally friendly and economically viable rejuvenator encapsulation method, where the calcium alginate is used as rejuvenator encapsulation material. The capsule morphology and microstructure were studied using the Microscopy and X-ray tomography. Capsules thermal and mechanical …

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The Role Of Dense Slurry In Achieving Zero Liquid Discharge, D.M. Timmons, Istvan Kovacsics Jan 2018

The Role Of Dense Slurry In Achieving Zero Liquid Discharge, D.M. Timmons, Istvan Kovacsics

Coal Combustion and Gasification Products Journal Archive

The Coal Combustion Residual (CCR) and Effluent Limitations Guidelines (ELGs) rules pose significant technical and economic challenges for ash management and for treatment and discharge of flue gas desulfurization (FGD) wastewater at coal-fired power plants. Beneficial use is always a priority for ash, but only about half is being reused on a national basis, and the rest is destined for disposal. The U.S. Environmental Protection Agency identified biological treatment as the baseline treatment technology for FGD wastewater in the ELGs. However, it is becoming evident that bioreactors exhibit high capital and operating costs, occupy significant space, and are sensitive to …

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Evaluation Of 2-Cell Rc Box Culverts, Hossein Sharifi Jan 2018

Evaluation Of 2-Cell Rc Box Culverts, Hossein Sharifi

Theses and Dissertations--Civil Engineering

Reinforced Concrete Box Culverts (RCBCs) are an integral part of the national and international transportation infrastructure. The National Bridge Inventory Standards (NBIS) requires that all bridges, which include culverts with spans ≥ 20 ft. (6.1 m), be load rated for safe load carrying capacity in accordance with the AASHTO Manual for Bridge Evaluation (MBE). In Kentucky, the Transportation Cabinet manages more than 15,500 bridges, of which almost 1,400 are bridge size culverts. Of the 1241 bridge size RCBCs that were being evaluated in Kentucky between 2015 and 2018, 846 were 2-cell culverts (or 68%). The objective in this study is …

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Risk Management And Practice Alignment For Utility Coordination On Transportation Projects, Roy E. Sturgill Jr. Jan 2018

Risk Management And Practice Alignment For Utility Coordination On Transportation Projects, Roy E. Sturgill Jr.

Theses and Dissertations--Civil Engineering

Utility coordination is an exceedingly complex effort of managing, communicating, and facilitating the avoidance and relocation of utility facilities as needed for highway projects. Utility coordination occurs throughout the design and delivery of a project and best practices are used to make sure this occurs efficiently and in the best interest of the public, who are not only the taxpayers but also the ratepayers. Recent research has attempted to enhance utility location technology and procedures, instill frameworks and tools for utility coordination, and proceduralize risk management relative to utility coordination. However, research attempting to improve various aspects of utility coordination …

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Investigation Of Volatile Organic Compounds (Vocs) Detected At Vapor Intrusion Sites, Mohammadyousef Roghani Jan 2018

Investigation Of Volatile Organic Compounds (Vocs) Detected At Vapor Intrusion Sites, Mohammadyousef Roghani

Theses and Dissertations--Civil Engineering

This dissertation investigates unexplained vapor intrusion field data sets that have been observed at hazardous waste sites, including: 1) non-linear soil gas concentration trends between the VOC source (i.e. contaminated groundwater plume) and the ground surface; and, 2) alternative pathways that serve as entry points for vapors to infiltrate into buildings and serve to increase VOC exposure risks as compared to the classic vapor intrusion model, which primarily considered foundation cracks as the route for vapor entry. The overall hypothesis of this research is that theoretical knowledge of fate and transport processes can be systematically applied to vapor intrusion field …

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Lies, Damned Lies, Avs, Shared Mobility, And Urban Transit Futures, Graham Currie Jan 2018

Lies, Damned Lies, Avs, Shared Mobility, And Urban Transit Futures, Graham Currie

Journal of Public Transportation

It seems to me there is a gigantic lot of nonsense discussed about the future of transport and the future of public transport in particular. As a researcher in the field, I find my emotions boiling over. I get angry at blanket statements telling us public transport has no future and it seems to me much of what is talked about regarding transport futures flies in the face of facts and a long history of what knowledge has gleaned about the human condition, economics, cities, and travel. My hope is that readers will see prevailing discourse differently as a result …

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Does The Future Of Mobility Depend On Public Transportation?, Kari Watkins Jan 2018

Does The Future Of Mobility Depend On Public Transportation?, Kari Watkins

Journal of Public Transportation

We’ve all seen the headlines. “Will self-driving cars, taxis make mass transit obsolete?” (Davidson 2017) and “What happens if Uber or Lyft outcompetes public transit?” (Sen 2017) or even “Department Of Transportation Says The Future Of Transit Looks Pretty Bleak” (Griggs 2015). We are entering the next great revolution in how people move about in cities. But does the future of transportation mean the end of transit?

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Improved Mobility Through Blurred Lines, Carol Schweiger Jan 2018

Improved Mobility Through Blurred Lines, Carol Schweiger

Journal of Public Transportation

No abstract provided.

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Better Integrating Travel Choices Into Future Urban Mobility Systems: The Day The Highways Stood Still, Eric Schreffler Jan 2018

Better Integrating Travel Choices Into Future Urban Mobility Systems: The Day The Highways Stood Still, Eric Schreffler

Journal of Public Transportation

No abstract provided.

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Not If, But When: Autonomous Driving And The Future Of Transit, Jerome M. Lutin Jan 2018

Not If, But When: Autonomous Driving And The Future Of Transit, Jerome M. Lutin

Journal of Public Transportation

This paper discusses the implications of autonomous vehicle technology on auto use and travel behavior, and the resulting impacts on public transportation. The paper goes on to explore how autonomous driving technology can make more efficient use of bus transportation and improve service to disabled individuals. The paper concludes with recommendations for transit agencies to engage with government and suppliers of autonomous vehicles to promote research, development, and policies that will allow the industry to reap the benefits of this revolutionary and disruptive technology.

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Reflections On The Future Of Public Transportation, Joel Volinski Jan 2018

Reflections On The Future Of Public Transportation, Joel Volinski

Journal of Public Transportation

No abstract provided.

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A Synthesis Of Mobile Ticketing Applications Used By Commuter Railroads In The United States, Jonathan Mesoraca, Candace Brakewood Jan 2018

A Synthesis Of Mobile Ticketing Applications Used By Commuter Railroads In The United States, Jonathan Mesoraca, Candace Brakewood

Journal of Public Transportation

Since 2012, many major commuter railroads have deployed mobile ticketing applications (or “apps”) that allow passengers to pay fares directly using their smartphones. In light of this rapid technological change, this research aims to provide a synthesis of the current state of mobile ticketing in the United States. The 14 largest commuter railroads that have launched mobile ticketing apps are compared in four different areas: (1) the ticket validation process; (2) ticket types offered in the mobile app; (3) additional features in the app; and (4) the process for transferring to other modes using the app. The results reveal that …

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Ex-Regular Users Of Public Transport: Their Reasons For Leaving And Returning, Paula Vicente, Elizabeth Reis Jan 2018

Ex-Regular Users Of Public Transport: Their Reasons For Leaving And Returning, Paula Vicente, Elizabeth Reis

Journal of Public Transportation

This paper describes the characteristics of former regular users of public transport in the metropolitan area of Lisbon. It also examines why these people stopped using public transport and explores what would make them become regular users again. The empirical results revealed significant socio-demographic differences between current and ex-regular users, namely in relation to gender and social level. Differences were also found in travel characteristics, car ownership, and satisfaction with the transit service. The main reasons given by ex-regular users for no longer using public transport included changes in their lives (e.g., change in workplace/residence/ school or becoming unemployed) and …

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Stormwater Capture In The Built Watershed: Fostering Public Awareness Of Water Conservation Through A Parcel-Level Approach To Stormwater Management, Benjamin Rigby Jan 2018

Stormwater Capture In The Built Watershed: Fostering Public Awareness Of Water Conservation Through A Parcel-Level Approach To Stormwater Management, Benjamin Rigby

Pitzer Senior Theses

As California contends with climate change and more extreme cycles of drought and deluge, water management agencies and conservation groups are looking towards solutions to the decreasing reliability of imported water supplies. Stormwater has historically been perceived as a threat to development but when captured properly, it presents a resource that can augment local water supplies. Solutions to water supply issues in California have traditionally employed technical and centrally controlled methods for importing water, but there is a growing understanding that parcel-level capture through vegetated swales presents an opportunity for reducing the impact that development has on California’s hydrology. Vegetated …

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Assessing The Application Of The Unmanned Aerial Systems (Uas) In Earthwork Volume Measurement, Xi Wang Jan 2018

Assessing The Application Of The Unmanned Aerial Systems (Uas) In Earthwork Volume Measurement, Xi Wang

Theses and Dissertations--Civil Engineering

Earthwork operations are often one of the major cost items on infrastructure construction projects. Because earthwork is largely influenced by unstable construction conditions and organization plans, it becomes the emphasis and difficulties of the cost control in the construction process. Therefore, precise estimates of actual earthwork volumes are important for both owners and contractors alike to ensure appropriate payments are made. However, measuring work on site requires lots of time and labors because of various and irregular site conditions. Conventional measurement methods, such as planned quantities from the drawings or estimates from equipment activity, are rough estimates with significant opportunities …

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Effect Of Socioeconomic And Demographic Factors On Kentucky Crashes, Aaron Berry Cambron Jan 2018

Effect Of Socioeconomic And Demographic Factors On Kentucky Crashes, Aaron Berry Cambron

Theses and Dissertations--Civil Engineering

The goal of this research was to examine the potential predictive ability of socioeconomic and demographic data for drivers on Kentucky crash occurrence. Identifying unique background characteristics of at-fault drivers that contribute to crash rates and crash severity may lead to improved and more specific interventions to reduce the negative impacts of motor vehicle crashes. The driver-residence zip code was used as a spatial unit to connect five years of Kentucky crash data with socioeconomic factors from the U.S. Census, such as income, employment, education, age, and others, along with terrain and vehicle age. At-fault driver crash counts, normalized over …

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Dust Control Examination Using Computational Fluid Dynamics Modeling And Laboratory Testing Of Vortecone And Impingement Screen Filters, Ashish R. Kumar Jan 2018

Dust Control Examination Using Computational Fluid Dynamics Modeling And Laboratory Testing Of Vortecone And Impingement Screen Filters, Ashish R. Kumar

Theses and Dissertations--Mining Engineering

Heavy industries, such as mining, generate dust in quantities that present an occupational health hazard. Prolonged exposure to the respirable dust has been found to result in many irreversible occupational ailments in thousands of miners. In underground mining applications, a variety of scrubbing systems are used to remove dust near the zones of generation. However, the wire-mesh type fibrous screens in the flooded-bed dust scrubbers used on continuous miners, are prone to clogging due to the accumulation of dust particles. This clogging results in a reduced capture efficiency and a higher exposure to the personnel. This research establishes the Vortecone, …

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Comparison Of Three Regionalization Techniques For Predicting Streamflow In Ungaged Watersheds In Nebraska, Usa Using Swat Model, Michael W. Van Liew, Aaron R. Mittelstet Jan 2018

Comparison Of Three Regionalization Techniques For Predicting Streamflow In Ungaged Watersheds In Nebraska, Usa Using Swat Model, Michael W. Van Liew, Aaron R. Mittelstet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study compared three approaches, regional averaging, nearest neighbor, and donor techniques, to regionalize parameters in the Soil and Water Assessment Tool (SWAT) on eleven watersheds located in the Dissected Plains, Plains, and Rolling Hills Landforms in the eastern portion of the State of Nebraska, USA. Within the Rolling Hills Landform, three watersheds were randomly selected as calibration watersheds while two were randomly selected as validation watersheds. Two watersheds were randomly selected as calibration watersheds while one was randomly selected as a validation watershed within each of the Dissected Plains and Plains Landforms. The seven calibration watersheds were used to …

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Compressibility Of Fly Ash Under Ko Loading: Strain Rate Effects In Constant Rate Of Strain Testing, Jaime A. Mercado, Luis G. Arboleda-Monsalve, Tarunjit S. Butalia, Pedro J. Amaya Jan 2018

Compressibility Of Fly Ash Under Ko Loading: Strain Rate Effects In Constant Rate Of Strain Testing, Jaime A. Mercado, Luis G. Arboleda-Monsalve, Tarunjit S. Butalia, Pedro J. Amaya

Coal Combustion and Gasification Products Journal Archive

Coal combustion processes produce large volumes of fly ash. The compressibility of fly ash was studied using moist tamping and drypluviation methods to achieve different void ratios before subjecting the material to compressive oedometric Ko loading (i.e., zero lateral deformation throughout the test). The class F fly ash used in this research was produced at a Midwest U.S. power plant. The material was initially characterized with hydrometer and specific gravity tests, and maximum and minimum realizable void ratios were determined. The compressibility characteristics of the fly ash material were studied at four strain rates, 1%/h, 10%/h, 40%/h, and 100%/h, and …

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