Engineering Commons^™

Prediction And Rehabilitation Of Highway Embankment Slope Failures In Changing Climate, Navid Jafari, Anand Puppala

Publications

Highway slopes constructed with clayey soil are prone to desiccation cracks due to wetting and drying weather cycle, which allows greater moisture infiltration into the embankment from precipitation. Fissures formed due to extended wetting and drying cycles allow water to seep deeper into the soil than surficial wetting and increase the water content. This increases the moisture content in the soil and results in reduction in shear strength to the fully softened strength. On the other hand, development of desiccation cracks and reduction of the soil matric suction ultimately result in higher hydraulic conductivity value which causes development of higher …

Impacts Of Moisture On Asphalt Properties, Zahid Hossain

Publications

Stripping related moisture damage has been recognized as one of the major pavement distresses since the early 1990s. The main objective of this study is to establish an effective test protocol to quantify moisture susceptibility of asphalt pavements. To this end, selective test methods (Texas Boiling test, Tensile Strength Ratio, Retained Stability, and Hamburg Wheel Test), and procedures based on surface chemistries and molecular-level mechanistic properties have been investigated in this study. Firstly, a comprehensive list of literature related to moisture damage in asphalts was reviewed. Based on the literature review, a detailed project plan and test matrix were developed. …

Enhancing The Durability And The Service Life Of Asphalt Pavements Through Innovative Light-Induced Self-Healing Materials, Marwa Hassan

Publications

The objective of this study was to evaluate the efficiency of a new generation of Ultraviolet (UV) light-induced selfhealing polymers in enhancing the durability and self-healing properties of asphalt mixtures. Self-healing polymers were successfully synthesized in the laboratory and were characterized using Fourier Transform Infrared Spectroscopy (FTIR). In addition, Thermogravimetric Analysis (TGA) results showed that the synthesized polymers achieved the required thermal stability to resist asphalt mixture production processes. Viscosity results showed that addition of 5% Recycled Asphalt Shingle (RAS) and/or 20% Reclaimed Asphalt Pavement (RAP) caused an increase in the viscosity of the binder blends. However, a reduction in …

Evaluation Of The Performance And Cost-Effectiveness Of Engineered Cementitious Composites (Ecc) Produced From Region 6 Local Materials, Gabriel Andres Arce Amador, Tyson Rupnow, Marwa Hassan

Publications

The project objective is to develop cost-effective Engineered Cementitious Composites (ECC) with locally available ingredients in Region 6 to address the deficiencies observed in ordinary concrete materials. The study explored the utilization of two types of river sands (coarse and fine), two types of PVA fibers (long and short), four levels of cement replacement with Class F fly ash, and the implementation of recycled crumb rubber in the performance of ECC materials. A total of 24 mix designs were prepared and evaluated in compression, tension, and bending to assess its mechanical properties. Furthermore, the cracking characteristics of the materials produced …

Modeling Sulfate Attack In Modern Concrete For Building Sustainable And Resilient Infrastructure, Zachary Grasley

Publications

External sulfate attack is a complex phenomenon and is manifested in the form of large expansion, cracking, and spalling depending on the exposure solution and material constituent properties. Several models were developed in the past to demonstrate sulfate attack mechanisms that account for the diffusion of sulfate ions into the porous concrete and the successive deformation triggered by the chemical reaction and precipitation of expansive agents. However, none of these models accounts for the effect of the migration of solvent water from the low solute concentration solution to high solute concentration solution driven by the osmotic pressure. Osmotic pressure is …

In-Situ Mechanical Characterization For Compacted Aggregates, Douglas Cortes, Paola Bandini

Publications

The evaluation of compacted unbound aggregate layers is perhaps the most common undertaking in transportation-related projects. The assessment of compaction compliance in engineered fills, subgrades, subbases, and bases in roadways and railways is central to ensure longevity of ground transportation infrastructure. In many cases, premature failures in roadways that originate in the unbound aggregate layers can be traced back to inadequate compaction. These failures are preventable, provided the problem areas can be identified by a suitable field test during construction. The most widely used method for compaction assessment during construction is the nuclear density gauge (NDG) test. While the device …

Bridge Inspecting With Unmanned Aerial Vehicles R&D, Paul Darby, Vijaya Gopu

Publications

The project achieves through research including literature, on site interviews, and experimentation: 1) a recommendation for a UAV-based system to practically assist in routine bridge inspection work in the State of Louisiana, 2) the identification and description of advantages, disadvantages, and limitations in the use of UAVs for routing bridge inspection work in Louisiana, and 3) provided recommendations for future work. The Yuneec H520 aircraft and its E90 camera are recommended, as is the need for a boat to be included as part of the system. The recommended system has advantages in reaching portions of the bridge that are difficult …

Use Of Rice Hull Ash (Rha) As A Sustainable Source Of Construction Material, Zahid Hossain, Ashraf Elsayed

Publications

With the imminent shortage of natural resources, the need to find sustainable development is the highest in recent history. Therefore, this study examines the potential uses of Rice Hull Ash (RHA) as a sustainable cementitious material (SCM) in preparation of concrete. This study also assesses the use of RHA as an alternative of commonly used polymers in preparing high-grade asphalt binders. RHA is a potential sustainable solution because it is currently being treated as an agricultural waste material, yet its high silica content makes it a potential construction material. Three different sizes of RHA (600 µm, 150 µm, and 44 …

Use Of Nanoclays As Alternatives Of Polymers Toward Improving Performance Of Asphalt Binders, Zahid Hossain, Ashraf Elsayed

Publications

The main goal of this study is to assess the feasibility of the use of nanoclay as an alternative to commonly used polymers such as styrene-butadiene-styrene (SBS), which are used to modify the performance grade (PG) of asphalt binders. Three types of nanoclay and two types of neat binders were selected for laboratory investigation. Different amounts (1, 2, and 3%) of nanoclays were used. A blending protocol has been developed to mix the nanoclay with the asphalt binder. Rotational Viscosity (RV), Dynamic Shear Rheometer (DSR), Optical Contact Analyzer (OCA) and Atomic Force Microscope (AFM) were conducted to evaluate the properties …

Development Of A Self-Healing And Rejuvenating Mechanisms For Asphalt Mixtures Containing Recycled Asphalt Shingle, Marwa Hassan

Publications

The objective of this study was to test the hypothesis that hollow-fibers encapsulating a rejuvenator product could improve both self-healing, rejuvenation, and mechanical properties of asphalt mixtures. Hollow-fibers containing a rejuvenating product were synthesized via a wet spinning procedure with sodium-alginate polymer as the encapsulating material. An optimization of the production parameters for the synthesis of fibers was performed to develop fibers suitable for high-temperature and shear stress environment typical of asphalt mixture production. A self-healing experiment was conducted to evaluate the healing/rejuvenation capabilities of sodium-alginate fibers in asphalt mixtures with varying types of binders and recycled materials. Based on …

Development Of A Standard Test Method For Characterization Of Asphalt Materials And Aging-Related Degradation Using An Extensional Rheometer, Nazimuddin Wasiuddin

Publications

An extensional deformation test method using a Sentmanat Extensional Rheometer (SER) fixture inside a Dynamic Shear Rheometer (DSR) is developed in this study to investigate the degradation of the polymer due to aging and to investigate the effect of modifier type. A relationship between different percentages of modifier and ductility of the modified binder is also investigated. The sample geometrics used in this study are 1 mm x 0.72 mm and 3 mm x 0.72 mm. A total of one hundred and sixty-two samples were tested. Three modifiers Styrene-Butadiene-Styrene (SBS), Polyphosphoric Acid (PPA) and latex were used. One PG 76-22, …

Development Of Environmentally-Friendly Stabilization Methods For Transportation Infrastructure Based On Geopolymers, Miladin Radovic, Anand Puppala

Publications

Geopolymers (GPs) have received much attention as an eco-friendly and sustainable alternative to conventional chemical additives, since they can be processed at room temperatures from aqueous solutions by utilizing waste materials (e.g. fly ash) or abundant natural sources (e.g. clay). A collaborative research study is carried out by teams from Texas A&M University (TAMU) and University of Texas at Arlington (UTA) to investigate the effectiveness of GPs for stabilizing base and subgrade materials by considering the strength and shrink-swell characteristics. Two types of clay, obtained from the North Dallas area, were mixed with a potassium-based GP synthesized from metakaolin and …

Sustainable And Equitable Financing For Pedestrian Infrastructure Maintenance, Gregory Rowangould

Publications

In many communities, pedestrian infrastructure is discontinuous, inaccessible to those with physical disabilities, and poorly maintained. Correcting these problems would be a first step in providing infrastructure to achieve the active travel and related transportation goals of many communities. One nearly universal challenge to maintaining sidewalks in a state of good repair and addressing environmental justice concerns is an adequate, sustainable, and equitable source of funding. Municipal governments across the country maintain and repair their streets and roadways; however, most require residents to maintain and repair public sidewalks adjacent to their property. These policies are difficult to enforce and may …

Bridge Deck Overlays Using Ultra-High Performance Concrete, Craig Newtson, Brad Weldon

Publications

This study investigated the use of a locally produced ultra-high performance concrete (UHPC) as an alternative to typical overlay materials. Several bond strength tests including slant-shear, splitting tension, and direct tension tests were performed to assess the bond strength between UHPC and normal strength concrete (NSC) substrate with varying surface textures. Tests were also conducted to assess the early-age and longer-term shrinkage behavior and coefficient of thermal expansion of the UHPC as well as rapid chloride permeability testing. Good bond between UHPC and NSC substrate was observed even with inadequate surface texture. Combined shrinkage and thermal effects were investigated for …

Design, Simulation, And Construction Of An Ieee 14-Bus Power System, John Albert Boudreaux

LSU Master's Theses

Today’s bulk power system is massive, complex, and very dynamic. The U.S. power grid spans from coast to coast and even as far reaching as Canada. With the addition of new technologies such as renewable energies and power electronics to aid in power conversion and control, the power system grows more complex by the day. The most common approach of analyzing power system stability is through computer modeling and simulation. Due to the vast size and inaccessibility of transmission systems, real time testing can prove difficult. The motivation of this project was to design, simulate, and construct an IEEE 14 …

Chemically Modified Cellulosic Materials As Multi-Functional Agents In Polymer Composites, Jinlong Zhang

LSU Doctoral Dissertations

Comparative flame retardancy of micro wood fiber plastic composites (WPCs) with fire retardants (1,2-bis(pentabromophenyl) ethane, metal hydroxides and nanoclay) was studied. The fire additives (1,2-bis(pentabromophenyl) ethane as well as magnesium hydroxide) obviously enhanced the fire retarding properties of WPCs. Especially, 1,2-bis(pentabromophenyl) ethane significantly reduced the total heat release as well as heat release rate. In addition, a synergistic effect of 1,2-bis(pentabromophenyl) and nanoclay was achieved for the enhanced fire retarding performance of WPCs.

A copolymer of cellulose nanocrystals (CNCs) and poly(N-vinylcaprolactam) (PVCL) (PVCL-g-CNCs) for use as thermally-responsive polymers with low critical solution temperatures (LCSTs) was synthesized via atom transfer radical …

Field Instrumentations And Numerical Analysis Of Geosynthetic Reinforced Soil – Integrated Bridge System (Grs-Ibs), Allam Ardah

LSU Doctoral Dissertations

Geosynthetic reinforced soil (GRS) is a special soil with geosynthetic fabric closely stacked in layers as soil stabilization and considered an alternative design method to the conventional bridge support technology. In this research study, a field case study of Maree Michel bridge, which is located in Route LA 91 Vermilion Parish in Louisiana, was instrumented with six different types of instrumentations to monitor the performance of GRS-IBS bridge abutment and to develop 2D and 3D finite element models. The instrumentations include Shape Acceleration Array (SAA), earth pressure cells, strain gauges, piezometers, and thermocouples. Additionally, surveying was conducted at the bridge …

Techniques Of Energy-Efficient Vlsi Chip Design For High-Performance Computing, Zhou Zhao

LSU Doctoral Dissertations

How to implement quality computing with the limited power budget is the key factor to move very large scale integration (VLSI) chip design forward. This work introduces various techniques of low power VLSI design used for state of art computing. From the viewpoint of power supply, conventional in-chip voltage regulators based on analog blocks bring the large overhead of both power and area to computational chips. Motivated by this, a digital based switchable pin method to dynamically regulate power at low circuit cost has been proposed to make computing to be executed with a stable voltage supply. For one of …

Engineering Metal-Ligand Interface For Selective Electrochemical Carbon Dioxide Reduction, Yuxin Fang

LSU Doctoral Dissertations

Unsustainable exploitation of fossil fuel and its massive greenhouse gas emission necessitates the development in alternative energy sources. Chemical fuels (CH₃OH or C₂H₅OH) outperform other choices, such as batteries for their high energy densities, which is key to portability. Electrochemical reduction of CO₂is capable of producing a wide range of valuable fuels (Syngas, formic acid, methane and methanol, etc.). Converting CO₂into carbon-based fuels further closes the carbon neutral cycle, which contributes to the effort in reducing global CO₂emission. Integration of organic ligands with transition metals shows great potential …

Spectrum- And Energy-Efficient Radio Resource Allocation For Wireless Communications, Shengjie Guo

LSU Doctoral Dissertations

Wireless communications has been evolved significantly over the last decade. During this period, higher quality of service (QoS) requirements have been proposed to support various services. In addition, due to the increasing number of wireless devices and transmission, the energy consumption of the wireless networks becomes a burden. Therefore, the energy efficiency is considered as important as spectrum efficiency for future wireless communications networks, and spectrum and energy efficiency have become essential research topics in wireless communications. Moreover, due to the exploding of number mobile devices, the limited radio resources have become more and more scarce. With large numbers of …

Investigation Of Flow Mechanisms In Gas-Assisted Gravity Drainage Process, Iskandar Dzulkarnain

LSU Doctoral Dissertations

In this study we investigate displacement mechanism for oil recovered using Gas- Assisted Gravity Drainage (GAGD) method. For a typical oil recovery under gravity drainage, the recovery profile can be characterized by an initial bulk flow which occurs rapidly and a later film flow that extends for a longer duration. It is the latter period where film spreading, the ability of oil to spread above water in the presence of gas, is identified as the displacement mechanism responsible for recovering the remaining oil in gravity drainage process. Literature survey indicates that mathematical models for gravity drainage do not account for …

Evaluation Of Undrained Shear Strength And Soil Classification From Cone Penetration Test, Md Imran Hossain

LSU Master's Theses

The in-situ cone and piezocone penetration tests (CPT, PCPT) has been widely used by the geotechnical engineering community for subsurface soil characterization and classification, and for the evaluation of many engineering soil properties, such as undrained shear strength (s_u), unit weight (γ), constrained modulus (M), coefficient of consolidation (c_v), and stress history (OCR). The objective of this research study was to estimate the undrained shear strength of clayey soil using CPT/PCPT data in addition to some soil boring log data. At the same time, soil classification charts/methods based …

Development Of Long-Term Aging Factor For Asphalt Mixtures’ Cracking Resistance, Yucheng Shi

LSU Master's Theses

To characterize the cracking resistance of asphalt mixtures, semi-circular bend (SCB) test has been developed and subsequently accepted as a routine test in mixture design in Louisiana. However, SCB test requires specimens to be aged for five days in laboratory, which makes it not implementable in quality control (QC)/quality assurance (QA).

The primary project objective was to develop an aging factor to transfer the unaged SCB Jc to the aged SCB Jc. Specific objectives were to: (1) investigate the effect of laboratory aging on asphalt mixtures’ cracking resistance and asphalt binders’ rheological and chemical properties, (2) develop an aging …

Coupled Thermo Mechanical Modeling Of Friction Stir Welding And Fatigue Life Improvement Of Friction Stir Welding Structures, Saad Bin Aziz

LSU Doctoral Dissertations

Friction- stir- welding (FSW) is comparatively a new welding process invented by The Welding Institute in 1991. Since no melting or fusion occurs during the welding process, FSW is free of high heat input and solidification defects. Two main objectives have been set forth in this work. The first object of this thesis is to develop thermomechanical models based on experimental knowledge and understanding the FSW process at a fundamental level. The quality of friction-stir-welding (FSW) joints depends on many critical weld process parameters. The main challenge for the FSW is in the selection of these critical process parameters that …

Investigation Of Flow Mechanisms In Gas-Assisted Gravity Drainage Process, Iskandar Dzulkarnain

LSU Doctoral Dissertations

In this study we investigate displacement mechanism for oil recovered using Gas- Assisted Gravity Drainage (GAGD) method. For a typical oil recovery under gravity drainage, the recovery profile can be characterized by an initial bulk flow which occurs rapidly and a later film flow that extends for a longer duration. It is the latter period where film spreading, the ability of oil to spread above water in the presence of gas, is identified as the displacement mechanism responsible for recovering the remaining oil in gravity drainage process. Literature survey indicates that mathematical models for gravity drainage do not account for …

Development Of Self-Healing Mechanisms For Asphalt Pavements, Max Abelardo Aguirre Deras

LSU Doctoral Dissertations

Self-healing mechanisms, such as microcapsules or hollow-fibers, filled with an asphalt rejuvenator present an emerging technology that would enhance an asphalt mixture’s resistance to cracking damage caused by vehicular and environmental loading. The objectives of this study were to: (a) Evaluate the effects of asphalt rejuvenators on hot-mix asphalt mixtures in order to test its effects on the fundamental engineering properties of the mixtures at high and intermediate temperatures; (b) Develop a synthesis procedure for production of microcapsules and hollow-fibers containing an asphalt rejuvenator; (c) Evaluate the self-healing efficiency of double-walled microcapsules and hollow-fibers filled with an asphalt rejuvenator, through …

A Study On Reduction Of Harmonic Distortion Caused By Ac Arc Furnaces, Venkata Mani Gadiraju

LSU Master's Theses

In AC arc furnaces, arc ignition is stabilized by inductors which are connected across its supply lines. They cause power factor degradation in the system. When furnaces are modelled as linear RL load, the arc nonlinearity reduces the impact of this degradation to a significant extent. Furnace Power factor is improved by the DC voltage on the arc. In this research study, power factor of AC furnaces is estimated on the assumption that DC voltage on the arc is constant and furnace operates in steady state. Primary objective of this research was to determine the power factor of the furnace …

Evaluation Of Site Variability And Its Application In Design, Abu Hakim Muhammad Hasan Faisal

LSU Master's Theses

Geotechnical characterization has an important role in engineering geology as well as in implementation of any project. There are several variables and uncertainties involved in characterizing a project site. Four different sources of uncertainties represent the characterization of geotechnical variability, which include spatial variability, measurement error, statistical error and model bias. Spatial variability is expressed in terms of the mean, variance, and scale of fluctuation. Several statistical techniques such as the Gauge R & R, which includes X-Bar/R and ANOVA, and the Second Moment can be applied to compute site variability in terms of the coefficient of variations. Measurement error …

Direct Quantification Of Deubiquitinating Enzyme Activity In Single Intact Cells, Nora Safabakhsh

LSU Doctoral Dissertations

Challenges in drug efficacy occur during the treatment of most types of cancer due to the heterogeneity of the tumor microenvironment. This has led to the development of personalized medicine. Due to the clinical success of the proteasome inhibitors Bortezomib and Carfilzomib in treatment of multiple myeloma, interest has shifted towards molecularly-targeted chemotherapeutics for ubiquitin-proteasome system (UPS). Deubiquitinating enzymes (DUBs) are an essential part of this pathway which have been found to promote Bortezomib resistance in multiple myeloma patients. Unfortunately, there is a lack of specific, high throughput biochemical assays to characterize DUB activity in patient samples before and after …

Development Strategies For A Fractured, Heavy Oil Reservoir - Results From Numerical Simulations, German Albertovich Abzaletdinov

LSU Master's Theses

This research is focused on studying reservoir “N” in the Yarega heavy oilfield (YHOF) for development strategies and production optimization. YHOF is a naturally fractured heavy oil field where only very recently SAGD technology has been introduced. The motivation for this research is derived from the fact that SAGD employed in this field has so far resulted in early steam breakthrough leading to producer abandonment and new drilling, thus increasing costs. This study explores numerically different static and dynamic reservoir characterization models (single porosity versus dual porosity systems), and subsequent pressure-production history matched reservoir simulation for understanding heat and mass …