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University of Arkansas, Fayetteville

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Articles 61 - 90 of 434

Full-Text Articles in Civil and Environmental Engineering

Real-Time Barge Detection Using Traffic Cameras And Deep Learning On Inland Waterways, Geoffery Eyram Agorku Aug 2024

Real-Time Barge Detection Using Traffic Cameras And Deep Learning On Inland Waterways, Geoffery Eyram Agorku

Graduate Theses and Dissertations

Inland waterways are critical for freight movement, but limited means exist for monitoring their performance and usage by freight-carrying vessels, e.g., barges. While methods to track vessels, e.g., tug and tow boats, are publicly available through Automatic Identification Systems (AIS), ways to track freight tonnages and commodity flows carried on barges along these critical marine highways are non-existent, especially in real-time settings. This paper develops a method to detect barge traffic on inland waterways using existing traffic cameras with opportune viewing angles. Deep learning models, specifically, You Only Look Once (YOLO), Single Shot MultiBox Detector (SSD), and EfficientDet are employed. …

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Comparison Of Embodied Carbon Footprint Of A Mass Timber Building Structure With A Steel Equivalent, Mahboobeh Hemmati, Tahar Messadi, Hongmei Gu, Jacob Seddelmeyer, Moein Hemmati May 2024

Comparison Of Embodied Carbon Footprint Of A Mass Timber Building Structure With A Steel Equivalent, Mahboobeh Hemmati, Tahar Messadi, Hongmei Gu, Jacob Seddelmeyer, Moein Hemmati

Architecture Faculty Publications and Presentations

The main purpose of this study is to quantify and compare the embodied carbon (EC) from the materials used or designed to build the Adohi Hall, a residence building located on the University of Arkansas campus in Fayetteville, AR. It has been constructed as a mass timber structure. It is compared to the same building design with a steel frame for this study. Based on the defined goal and scope of the project, all materials used in the building structure are compared for their global warming potential (GWP) impact by applying a life cycle assessment (LCA) using a cradle-to-construction site …

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Micro-Mechanical Characterization Of Uhpc Stiffness Mechanisms: Towards A Better Understanding Of Concrete Elastic Modulus, Charissa N. Puttbach May 2024

Micro-Mechanical Characterization Of Uhpc Stiffness Mechanisms: Towards A Better Understanding Of Concrete Elastic Modulus, Charissa N. Puttbach

Graduate Theses and Dissertations

Current design code equations for estimating the elastic modulus of specialty concretes like ultra-high performance concrete are not all suitable. Developing empirical curves from exhaustive experimental testing is challenging for concretes that may have high levels of cement replacement with mineral admixtures and fibers at varying volume contents. As such, an alternative approach is taken that seeks to understand the constituent microscale stiffness mechanisms and relate the results to the macroscale. Micropillars are fabricated on several cement paste phases using a focused ion beam. A modified pico-indenter is used to determine the linear and non-linear behavior under micro-compression loading. Micropillar …

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Providing A Statistical Analysis Framework For Agencies To Analyze The Parameters Influencing The Rutting And Cracking Performance Of Asphalt Mixtures, Mohammad Tahir Ansari May 2024

Providing A Statistical Analysis Framework For Agencies To Analyze The Parameters Influencing The Rutting And Cracking Performance Of Asphalt Mixtures, Mohammad Tahir Ansari

Graduate Theses and Dissertations

Many state agencies recognize that their current asphalt mixtures are susceptible to cracking and poor durability. Some agencies are adjusting their mix design procedures to increase the asphalt binder content, while others are moving toward a balanced mix design (BMD) to try and address both cracking and rutting. However, there is uncertainty on what asphalt mixture properties can impact cracking and rutting. This research explores the IDEAL-CT and APA data from two years of mix designs collected by ARDOT. To understand which asphalt mixture properties impact cracking and rutting in the field, Pearson correlation (PCM), Spearman rank correlation (SCM) and …

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Proctor And Harvard Miniature Compaction Energy Comparison, Julia Loshelder May 2024

Proctor And Harvard Miniature Compaction Energy Comparison, Julia Loshelder

Graduate Theses and Dissertations

Compaction with the Harvard Miniature Compaction Apparatus (HMCA) was investigated to develop a method that can be used in place of typical Proctor compaction. Advantages for compaction with the HMCA include the need for less soil for testing and less preparation time. To investigate the potential for HMCA as a replacement, soil specimens were compacted with both the Proctor and HMCA methodologies at equivalent energies. For this testing, the testing included modified energy (56,250 ft-lbf/ft3 [2693 kN-m/m3]), standard energy (12,375 ft-lbf/ft3 [593 kN-m/m3]), and reduced energy (6188 ft-lbf/ft3 [296 kN-m/m3]). Because …

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Addressing Data Limitations Of Commercial Waterways Via Machine Learning And Stochastic Optimization, Sanjeev Bhurtyal May 2024

Addressing Data Limitations Of Commercial Waterways Via Machine Learning And Stochastic Optimization, Sanjeev Bhurtyal

Graduate Theses and Dissertations

Freight transportation is a crucial component of the US economy, with truck, rail, and water contributing significantly to the Gross Domestic Product (GDP). However, challenges arise in maintaining infrastructure capacity to accommodate the growing tonnage and value of freight transportation. Waterways offer high efficiency and environmental friendliness, with the capacity to transport substantial cargo volumes. Utilizing waterways can alleviate bottlenecks in landside transportation, accommodating the rising tonnage of commodity flow in the US. Despite the advantages of waterway transportation, the data limitations hinder informed decision-making regarding port operation and infrastructure investment. The lack of granularity and timeliness in available data …

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Cyclic Testing Of A Skewed Special Moment Frame Rbs Connection Having A Composite Concrete Slab, Adam Neil Kirchner May 2024

Cyclic Testing Of A Skewed Special Moment Frame Rbs Connection Having A Composite Concrete Slab, Adam Neil Kirchner

Graduate Theses and Dissertations

Special moment frames (SMFs) having reduced beam section (RBS) connections are commonly used in high seismic areas as they resist lateral forces while preserving critical welded connection regions. RBS SMFs provide brace-free, unobstructed frame options which can be favorable for architectural purposes. However, when building designs require non-rectangular framing, laterally skewed connections may be needed. Current design provisions for SMF connections provide only limited commentary on such non-orthogonal connections as limited research exists documenting skewed frame behavior. This study experimentally evaluates the cyclic behavior of a full-scale double-sided skewed SMF RBS specimen having a composite concrete slab. During the imposed …

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Use Of Bcsa Cement In Soil-Cement Mixtures As A Rapid Flood Repair Technique, Mariel Mayori Rivero May 2024

Use Of Bcsa Cement In Soil-Cement Mixtures As A Rapid Flood Repair Technique, Mariel Mayori Rivero

Graduate Theses and Dissertations

The research discusses the vulnerable condition of hydraulic structures, specially dams and levees located in the United States, structures that are often times made of earthfill material and that have been greatly impacted by recent flood events. The need for a rapid setting material for active flood fighting efforts is inarguable, in order to mitigate collateral expenses caused by the often long closure times when repair is taking place, especially when dewatering is necessary. Therefore, this research tested different proportions of cement in soil-cement mixtures at varying moisture contents with the interest of evaluating the performance of the soil-cement when …

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Effect Of Swirl Ratio On Simulated Vortech Chamber Vortex Parameters, Samuel Kolar May 2024

Effect Of Swirl Ratio On Simulated Vortech Chamber Vortex Parameters, Samuel Kolar

Civil Engineering Undergraduate Honors Theses

A numerical simulator can use computational fluid dynamics (CFD) to model an experimental tornado-simulating chamber at Texas Tech University (known as VorTECH). Previous studies evaluating this particular CFD model have produced results that compare the touchdown swirl ratio (STD), core radius (rc), maximum tangential velocity at touchdown (Vtmax @ STD), and height of the maximum tangential velocity (zc) reasonably well with experimental data from the VorTECH facility. The effects of swirl ratio beyond STD on important vortex parameters including rc, Vtmax, z …

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Examining The Relationship Between Manning's Roughness Coefficient And Stage, Henry Holtkamp May 2024

Examining The Relationship Between Manning's Roughness Coefficient And Stage, Henry Holtkamp

Biological and Agricultural Engineering Undergraduate Honors Theses

This paper uses LOESS regression to predict Manning's roughness coefficient to calculate flows in natural stream channels. Manning's roughness coefficient can introduce variability into Manning's equation, potentially destabilizing results. Utilizing LOESS to find n based on backcalculated n from collected discharge vs. stage information is the best way to acquire accurate Manning's roughness coefficient values at a variety of flows. Book values tend to drastically overestimate which can have wide-ranging implications for water allocation, flood management, maintaining environmental flows, and maintaining water quality.

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Examining The Impact Of Customer Rfp Characteristics On Award Compliance, Laasya Ravipati May 2024

Examining The Impact Of Customer Rfp Characteristics On Award Compliance, Laasya Ravipati

Data Science Undergraduate Honors Theses

In the context of intermodal transportation, understanding the dynamics of award compliance holds significant importance for operational efficiency and strategic decision-making. Award compliance refers to the percentage of awarded freight volume that is realized, indicating the extent to which contractual agreements are fulfilled. This analysis delves into the intricate relationship between customer characteristics and award compliance, aiming to provide valuable insights into the variability and predictability of compliance rates. By analyzing Request for Pricing (RFP) data and primary awarded freight volumes, the study seeks to address the need for more accurate volume estimations, crucial for sales planning, revenue projections, and …

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Investigation Into The Effect Of Mixture Composition On Setting Time Of Magnesium Phosphate Cement, Autumn Broglen May 2024

Investigation Into The Effect Of Mixture Composition On Setting Time Of Magnesium Phosphate Cement, Autumn Broglen

Civil Engineering Undergraduate Honors Theses

Magnesium phosphate cement (MPC) is a cementitious material that is formed through an acid-base reaction between magnesia and phosphate. This reaction occurs rapidly, making MPC an appealing choice for rapid repair applications. The purpose of this project is to investigate the impact of different proportions of class F fly ash, set retarder consisting of a mixture of boric acid and dextrose, magnesium to phosphate ratio, and water/cement ratio on the initial setting time of MPC paste. Different mixtures of MPC paste were developed to vary the proportions of each constituent, and setting time of each mixture was determined using the …

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Closing Dichloramine Decomposition Nitrogen And Oxygen Mass Balances: Relative Importance Of End-Products From The Reactive Nitrogen Species Pathway, Huong T. Pham, David G. Wahman, Julian L. Fairey Jan 2024

Closing Dichloramine Decomposition Nitrogen And Oxygen Mass Balances: Relative Importance Of End-Products From The Reactive Nitrogen Species Pathway, Huong T. Pham, David G. Wahman, Julian L. Fairey

Civil Engineering Faculty Publications and Presentations

In drinking water chloramination, monochloramine autodecomposition occurs in the presence of excess free ammonia through dichloramine, the decay of which was implicated in N-nitrosodimethylamine (NDMA) formation by (i) dichloramine hydrolysis to nitroxyl which reacts with itself to nitrous oxide (N2O), (ii) nitroxyl reaction with dissolved oxygen (DO) to peroxynitrite or mono/dichloramine to nitrogen gas (N2), and (iii) peroxynitrite reaction with total dimethylamine (TOTDMA) to NDMA or decomposition to nitrite/nitrate. Here, the yields of nitrogen and oxygen-containing end-products were quantified at pH 9 from NHCl2 decomposition at 200, 400, or 800 μeq Cl2·L …

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Decoding Usage And Adoption Behavior Of The Low-Carbon Transportation Market: An Ai-Driven Exploration, Vuban Chowdhury Dec 2023

Decoding Usage And Adoption Behavior Of The Low-Carbon Transportation Market: An Ai-Driven Exploration, Vuban Chowdhury

Graduate Theses and Dissertations

The transportation sector stands as a significant contributor to greenhouse gas emissions in the United States, with its environmental impact steadily escalating over the past few decades. This has prompted government agencies to facilitate the adoption and usage of low-carbon transportation (LCT) options as alternatives to fossil-fuel-powered transportation. LCTs include modes of transportation that minimize the overall carbon footprint of the transportation sector by relying on energy sources that are environmentally sustainable. These sustainable transportation options have also garnered significant interest in the transportation research community. For government agencies and researchers alike, a comprehensive understanding of the adoption and usage …

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Examining The Impact Of The Covid-19 Pandemic On Older Adults' Activity Participation And Mode Usage In A Rural State: A Case Study Of Arkansas, Arna Nishita Nithila Dec 2023

Examining The Impact Of The Covid-19 Pandemic On Older Adults' Activity Participation And Mode Usage In A Rural State: A Case Study Of Arkansas, Arna Nishita Nithila

Graduate Theses and Dissertations

The objective of the study was to investigate the impact of the COVID-19 pandemic on the activity participation and mode usage of older adults residing in Arkansas, a predominantly rural state. Leveraging primary data collected from 1,017 older adult participants, the study employed Latent Class Analysis (LCA) to capture older adults’ heterogeneity in travel behavior and found three distinct classes: Frequent Traveler, Moderate Traveler, and Non-Traveler, based on their activity participation, mode usage during the pandemic and the pandemic’s impact on their trips. Subsequently, a Multinomial Logit Model (MNL) was employed to examine how socio-demographic attributes, residential locations, and health …

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Determining The Effect Of The Presence Of Food Deserts On The Number Of Crashes In Census Tracts In Arkansas, Lizbeth Juarez-Bartolo Dec 2023

Determining The Effect Of The Presence Of Food Deserts On The Number Of Crashes In Census Tracts In Arkansas, Lizbeth Juarez-Bartolo

Graduate Theses and Dissertations

Food deserts, areas with limited access to grocery stores which sell fresh produce, dairy, and meats, are a growing concern in many communities. The presence of a food desert is known to cause great impacts on the physical health of the people residing within them, but there is little to no research on a food desert’s influence on the traffic safety of the location in which it encompasses. Based on previous studies into food deserts, studies suggest that food inaccessibility is mostly felt by rural residents. Since rural residents must travel farther distances on more hazardous rural roadways to access …

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Diffusive Gradients In Thin-Films Passive Samplers For Quantitation Of Per- And Polyfluoroalkyl Substances In Water: Kinetic Modeling, Experimental Methods, And Outlook For Regulatory Monitoring, Samuel Hodges Dec 2023

Diffusive Gradients In Thin-Films Passive Samplers For Quantitation Of Per- And Polyfluoroalkyl Substances In Water: Kinetic Modeling, Experimental Methods, And Outlook For Regulatory Monitoring, Samuel Hodges

Graduate Theses and Dissertations

Environmental sampling is the backbone of regulatory compliance in public water systems. Coupled with continuously improving analytical capabilities, grab sampling has revealed the ubiquity of emerging contaminants in water resources such as per- and polyfluoroalkyl substances (PFAS). The Environmental Protection Agency’s (EPAs) Method 533 and 537.1 specify 0.25 L grab samples undergo a solid phase extraction (SPE) to enrich PFAS up to 250-fold in 1 mL of methanol prior to analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This process can achieve lowest concentration minimum reporting levels (LCMRLs) between 0.53–16 ng•L−1 for the twenty-nine prioritized PFAS in drinking waters. However, toxicity …

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Self-Consolidating Concrete Design For Drilled Shaft Structural Applications, Grady S. Caton Dec 2023

Self-Consolidating Concrete Design For Drilled Shaft Structural Applications, Grady S. Caton

Graduate Theses and Dissertations

Self-consolidating concrete (SCC) is a relatively new concrete technology which allows the concrete to be placed without the need for manual or machine vibration. This innovation reduces labor costs, construction times, and can provide a smooth, finished surface. However, this technology is used in the United States primarily in the precast and prestressed concrete industry. The utility of SCC in structural applications, such as areas of dense reinforcement or locations where complex geometry makes consolidation impossible, is also advantageous. In this study, a series of SCC mixtures were developed both with and without fly ash replacement. These mixtures were then …

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Comparing In-Situ Liquefaction Triggering Procedures For Sites In Arkansas, Sagar Barua Dec 2023

Comparing In-Situ Liquefaction Triggering Procedures For Sites In Arkansas, Sagar Barua

Graduate Theses and Dissertations

There currently exists a significant amount of uncertainty when designing piles for bridge foundations in liquefiable soil. Currently ARDOT engineers use a Standard Penetration Test (SPT) based liquefaction spreadsheet developed 10 years ago to evaluate liquefaction triggering. Since this spreadsheet was developed, updates to the liquefaction triggering procedures have been published making the spreadsheet out-of-date. Moreover, additional methods of liquefaction evaluation using cone penetration test (CPT) and shear wave velocity (Vs) provide added means of evaluating liquefaction potential. This thesis updates ARDOT's liquefaction triggering evaluation methodology with the newest procedures and incorporates additional empirical liquefaction hazard estimates such as the …

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Developing Asphalt Mix Design Specifications Based On Apa And Ideal-Ct Testing, Jonathan Stonestreet Dec 2023

Developing Asphalt Mix Design Specifications Based On Apa And Ideal-Ct Testing, Jonathan Stonestreet

Graduate Theses and Dissertations

Some asphalt mixes, following the Superpave mix design procedure, have been reported to be too stiff, making cracking a prevalent form of pavement distress. Additionally, cracking has been reported to be the main form of distress of asphalt pavements in the State of Arkansas. These facts have heightened state agencies’ interest in better performing asphalt pavements, with Arkansas resolving to explore performance-based balanced mix designs (BMD), not yet explored in the state. The primary objective of this document is to present the completed study of balanced mix designs, based on the rutting and cracking potential of asphalt pavement mixtures through …

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Exploring The Potential Of Tesla Valve For Filtering And Sorting Microscale Active Swimmers: A Computational Study, Ariel Rogers, Zhiyao He, Yong Wang Dec 2023

Exploring The Potential Of Tesla Valve For Filtering And Sorting Microscale Active Swimmers: A Computational Study, Ariel Rogers, Zhiyao He, Yong Wang

Physics Faculty Publications and Presentations

It is well-known that a Tesla valve allows fluids to flow unidirectionally without moving parts; however, how Tesla valves interact with active matters and the potential applications of Tesla valves in biology remain largely unexplored. Here, we present a computational study on the potential use of Tesla valves for filtering and sorting microscale active swimmers such as bacteria. We investigated the behavior of microscale swimmers passing through the Tesla valve at different linear and angular velocities using numerical simulations and quantified the diodicity of the Tesla valve for active swimmers. Our results demonstrate that the Tesla valve can effectively filter …

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Verification Of Astm Centrifugation Equations For Soil Suction Determination, Esteban Maclein Miranda Pinzon Aug 2023

Verification Of Astm Centrifugation Equations For Soil Suction Determination, Esteban Maclein Miranda Pinzon

Graduate Theses and Dissertations

The unit correction constant (B) in the ASTM D6836 standard needs to be evaluated. The B-value was proposed to be 0.00548 instead of 0.00553. This apparent discrepancy led to an investigation comparing the predicted and measured suction values for high air entry (HAE) ceramic disks. A Beckman-Coulter Model J6-MI six-bay centrifuge and a WP4C Dewpoint Potentiameter were used in the testing program. HAE ceramic disks rated with bubbling pressures of 3-bar and 5-bar were used as analogue soil specimens. The HAE ceramic disks were spun in the small-scale centrifuge to apply prescribed suction amounts and then placed in the WP4C …

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Alkali Silica Reaction Mitigation Using Glycerin, Ana Laura Errigo Chanis Aug 2023

Alkali Silica Reaction Mitigation Using Glycerin, Ana Laura Errigo Chanis

Graduate Theses and Dissertations

The use of glycerin as a concrete additive to reduce alkali silica reaction (ASR), was evaluated and is presented in this study. Specifically, the United States Army Corps of Engineers (USACE) ultra-accelerated alkali silica reaction testing procedure by means of autoclaving was employed to examine the use of glycerin for ASR mitigation or reduction by analyzing mortar bar expansion data. The fine aggregates used in this investigation consisted of highly reactive Jobe Sand or Los Lunas Sand with an autoclave expansion of 0.5 and 0.4 percent, respectively. The laboratory investigation was performed by recording the amount of expansion of the …

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Uncovering The Spatio-Temporal Impact Of The Covid-19 Pandemic On Shared E-Scooter Usage: A Spatial Panel Model, Farzana Mehzabin Tuli, Arna Nishita Nithila, Suman Mitra Jul 2023

Uncovering The Spatio-Temporal Impact Of The Covid-19 Pandemic On Shared E-Scooter Usage: A Spatial Panel Model, Farzana Mehzabin Tuli, Arna Nishita Nithila, Suman Mitra

Civil Engineering Faculty Publications and Presentations

This study examines the spatio-temporal effects of the COVID-19 pandemic on shared e-scooter usage by leveraging two years (2019 and 2020) of daily shared micromobility data from Austin, Texas. We employed a series of random effects spatial-autoregressive model with a spatially autocorrelated error (SAC) to examine the differences and similarities in determinants of e-scooter usage during regular and pandemic periods and to identify factors contributing to the changes in e-scooter use during the Pandemic. Model results provided strong evidence of spatial autocorrelation in the e-scooter trip data and found a spatial negative spillover effect in the 2020 model. The key …

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Non-Steady-State Fickian Diffusion Models Decrease The Estimated Gel Layer Diffusion Coefficient Uncertainty For Diffusive Gradients In Thin-Films Passive Samplers, Samuel D. Hodges, David G. Wahman, Levi M. Haupert, Huong T. Pham, Margaret K. Bozarth, Michael B. Howland, Julian L. Fairey Jun 2023

Non-Steady-State Fickian Diffusion Models Decrease The Estimated Gel Layer Diffusion Coefficient Uncertainty For Diffusive Gradients In Thin-Films Passive Samplers, Samuel D. Hodges, David G. Wahman, Levi M. Haupert, Huong T. Pham, Margaret K. Bozarth, Michael B. Howland, Julian L. Fairey

Civil Engineering Faculty Publications and Presentations

Mass transport in diffusive gradients in thin-film passive samplers is restricted to diffusion through a gel layer of agarose or agarose cross-linked polyacrylamide (APA). The gel layer diffusion coefficient, DGel, is typically determined using a standard analysis (SA) based on Fick’s first law from two-compartment diffusion cell (D-Cell) tests. The SA assumes pseudo-steady-state flux, characterized by linear sink mass accumulation–time profiles with a typical threshold R2 ≥ 0.97. In 72 D-Cell tests with nitrate, 63 met this threshold, but the SA-determined DGel ranged from 10.1 to 15.8 × 10–6 cm2·s–1 (agarose) and …

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On The Micro-Mechanical Property Characterization And Bulk-Volume Behavior Prediction Of Additively Manufactured 17-4 Ph Stainless Steels, David González-Niño May 2023

On The Micro-Mechanical Property Characterization And Bulk-Volume Behavior Prediction Of Additively Manufactured 17-4 Ph Stainless Steels, David González-Niño

Graduate Theses and Dissertations

Selective laser melting is an additive manufacturing technology that opens the possibility to manufacture components with complex geometries that are difficult with traditional manufacturing techniques which could benefit engineering applications such as aviation or structural engineering. However, the lack of a reliable universal predictive model for selective laser melting components could impede the full implementation in industrial applications. Therefore, this dissertation investigates the mechanical behavior of selective laser melting 17-4 PH stainless steel under ultra-low cycle fatigue regime and propose a novel micro-mechanical based modeling using statistical and representative volume element. The first phase of this project examined the mechanical …

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Experimental Design For Determining The Cyclic Behavior Of Skewed Reduced Beam Section Moment Connections Having Composite Slabs, Paul Chabaud May 2023

Experimental Design For Determining The Cyclic Behavior Of Skewed Reduced Beam Section Moment Connections Having Composite Slabs, Paul Chabaud

Graduate Theses and Dissertations

This paper details the experimental design for determining the cyclic behavior of skewed Reduced Beam Section (RBS) moment connections having composite slabs. The effects of composite concrete slabs on skewed RBS connections subjected to cyclic seismic prequalification loading are addressed in this test setup. Full-scale double-sided RBS SMF specimens representing both interior and exterior column connections are designed and fabricated in this work. Experimental test fixturing and a lateral load application setup within the existing Grady E. Harvell Civil Engineering Research and Education Center (CEREC) are designed. All cyclic loading protocols required for the prequalification testing are described herein. Prequalification …

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Development Of Self-Stressing Ultra High-Performance Concrete Using Expansive Chemical Admixtures, Lane Edwards May 2023

Development Of Self-Stressing Ultra High-Performance Concrete Using Expansive Chemical Admixtures, Lane Edwards

Graduate Theses and Dissertations

This study investigated the effects of expansive chemical admixtures on ultra-high performance concrete (UHPC) and self-stressing mechanisms. A literature review was performed to determine different types of expansive admixtures for feasibility of the self-prestressing concept. Ultimately it was decided that type-k cement, made by combining Komponent admixture with conventional UHPC, was the most suitable option due to its effects on wet and hardened concrete properties. Mix designs with varying amounts of Komponent were developed to test the effects the admixture had on various properties. Tested properties included, workability, compressive strength, expansion, short-term shrinkage, long-term shrinkage, and developed prestress. The development …

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On The Feasibility Of Embedding Fe-Sma Short-Fibers In Ultra-High-Performance Concrete For Self Prestressing, Gavin Briggs May 2023

On The Feasibility Of Embedding Fe-Sma Short-Fibers In Ultra-High-Performance Concrete For Self Prestressing, Gavin Briggs

Graduate Theses and Dissertations

Prestressing concrete is common practice in the construction industry. Current prestressing methods are often used for large, straight members and come with geometric limitations for curved or thin-walled members. Shape memory alloy short fibers embedded within concrete mixes may allow for the prestressing of geometries not possible with traditional methods. This study reviews past research on prestressing concrete with shape memory alloys, evaluates the achievable recovery stress within an Fe-SMA (when deformed at room temperature), and examines the mechanical behavior of Ductal dark grey UHPC when heated to 250 °C. The flexural behavior, compressive strength, and fiber-to-concrete bond strength of …

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Bond-Breaker Properties Of Different Media For Concrete Pavement Design, Andres Calzacorta May 2023

Bond-Breaker Properties Of Different Media For Concrete Pavement Design, Andres Calzacorta

Graduate Theses and Dissertations

Currently Arkansas requires a layer of asphalt as the main bond-breaker over cement treated base for rigid pavement design. The study presented in this paper aims to replicate the results from previous research which demonstrated the bond-breaker properties of concrete curing compounds and geotextiles. Bond-breakers are materials applied to the surface of stabilized bases to reduce the interaction between the base and a pavement cement concrete layer. The excessive interaction between these two layers can lead to cracking in the overlay and reduction of the serviceability life of concrete. The curing compound was applied in a single application (SA, 200 …

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