Civil Engineering Commons^™

Field-Obtained Soil Water Characteristic Curves And Hydraulic Conductivity Functions, Elvis Ishimwe

Graduate Theses and Dissertations

A compacted clay liner (test pad) was constructed and instrumented with volumetric water content and soil matric potential sensors to determine soil water characteristic curves (SWCC) and hydraulic conductivity (k) functions. Specifically, the compacted clay liner was subjected to an infiltration cycle during a sealed double ring infiltrometer (SDRI) test followed by a drying cycle. After the drying cycle, Shelby tube samples were collected from the compacted clay liner and flexible wall permeability (FWP) tests were conducted on sub-samples to determine the saturated hydraulic conductivity. Moreover, two computer programs (RETC and UNSAT-H) were utilized to model the SWCCs and k-functions …

Assessment Of Nitrifying Bacteria In Massard Plant Using Molecular Tools, Jennifer Puanani Holmes-Smith

Civil Engineering Undergraduate Honors Theses

The discharge of nutrients (such as nitrogen and phosphorus) from wastewater treatment plants (WWTP) has become an increasingly important issue in the United States. Ammonia (NH3) is a common contaminant found in domestic wastewater and agricultural runoff. It can cause toxicity in fish if left untreated. The United States Environmental Protection Agency (EPA) recommends low national criteria for ammonia limits in freshwater. With these greater restrictions, ammonia-nitrogen limit compliance (5 mg/L) has become an issue at the Massard WWTP in Fort Smith, Arkansas. The purpose of this research is to assess the ammonia removal in the Massard WWTP in order …

A Comparison And Evaluation Of Different Dynamic Characterization Approaches For Bridges, Juan Javier Torres Torres Goitia

Graduate Theses and Dissertations

The objective of this thesis was to compare different dynamic characterization approaches for full scale bridge structures to devise a rapid and reliable Structural Health Monitoring (SHM) program in the aftermath of a natural or manmade hazard. Present methods for structural condition evaluation of bridge structures rely heavily on on-site visual inspections of each structure by specially trained engineers and technicians. It has been proved in the literature that this current method is subjective, time consuming and manpower intensive, all of which are not suited for the critical conditions following a hazard event. This study focused on comparing three different …

Comparing Ferrous Chloride And Ferrous Sulfate As Secondary Coagulants At The Beaver Water District Drinking Water Treatment Plant, Jenny Doyle

Graduate Theses and Dissertations

In November 2012, the Beaver Water District (BWD) switched primary oxidants from free chlorine to chlorine dioxide (ClO2) to curb formation of trihalomethanes, a regulated group of organic disinfection byproducts (DBPs). Because ClO2 is reduced to chlorite (ClO2-), a regulated inorganic DBP, BWD incorporated ferrous salt into their coagulation regime to quench chlorite to chloride. In this study, two ferrous salts - ferrous chloride (FC) and ferrous sulfate (FS) - were compared as secondary coagulants in combination with alum, the primary coagulant. Ferrous salts were dosed stoichiometrically to reduce chlorite and alum was dosed at percentages (0-100%) relative to a …

Global Dynamic Characterization And Load Rating Of Bridge Structures Utilizing Economical Dynamic Excitation Devices, Eric Fernstrom

Graduate Theses and Dissertations

Experimental modal analysis (EMA) of bridges and other civil structures can be used to acquire quantitative data describing their condition, and enhance opportunities for structural health monitoring and related fields. The use of EMA on civil structures has been limited by the high cost of the excitation devices that are required for the best data quality. The objective of the research reported herein is to evaluate a low-cost excitation system for multiple-input, multiple-output (MIMO) EMA, enabling the production of accurate estimates of the global behavior of in-service bridges.

The prototype excitation system is composed of consumer entertainment devices, namely tactile …

Rapid Condition Assessment Of Bridges By Falling Weight Deflectometer, Jeremy David Rawn

Graduate Theses and Dissertations

The objective of this thesis is to investigate the feasibility of using a Falling Weight Deflectometer (FWD) as an impact source to rapidly assess the condition of an in service bridge through the evaluation of its modal properties. Tests were conducted on two bridges, a Parker Pony Truss and a modern concrete deck on rolled steel beam bridge. Two full tests were performed on these structures with a hand held impact hammer and a falling weight deflectometer as sources for excitation. The advantage of using a FWD is that many transportation agencies already use these machines for pavement testing and …

The Investigation Of Cold-Mix Asphalt Creep Stiffness Testing Using Multiple Test Apparatuses And Gradations, Alexander Jackson

Graduate Theses and Dissertations

Many current methods of designing and testing Cold In-Place Recycled (CIR) asphalt are undesirable because they require large amounts of material and significant preparation. In an effort to lessen the cost and time of materials testing, this research utilizes several different methods of small scale testing of creep stiffness. These methods include using a Discovery Hybrid Rheometer (DHR) and a three point bending test to find the creep stiffness of emulsion based CIR. The new testing methods utilized samples on the scale of up to a hundredth the size of what the traditional methods of testing require. The two smaller …

The Characterization Of Foamed Asphalt Binders Using A Rotational Viscometer, John William Ryan

Graduate Theses and Dissertations

Foamed asphalt is a popular technic of vaporizing water into asphalt binder that falls under the umbrella term of warm-mix asphalt. In order to understand how to adjust mix designs for the use foamed asphalt, methods must be developed for characterizing different foamed asphalt binders. One way to characterize the asphalt binder is through viscosity testing using a rotational viscometer. The standard method of using a viscometer to measure the viscosity of asphalt binder is insufficient when dealing with foamed asphalts, so a new method has been created along with 4 metrics to analyze the data to characterize foamed asphalt …

Dynamic Excitation Related Uncertainty In Ambient Vibration Testing Of A Truss Bridge, Ryan T. Dufour

Civil Engineering Undergraduate Honors Theses

The aging and deteriorating state of bridges in the US, along with the many limitations of the visual inspection data that is used for assessing and evaluating their condition, have provided motivation for research on experimental methods to quantitatively describe and evaluate their in-situ performance and condition. Ambient vibration testing is one such global characterization approach that has been widely explored due to its low cost and ease of implementation for in-service bridges. The testing is used to identify the modal properties of the structure, typically the natural frequencies, mode shapes, and damping ratios. Although ambient vibration testing has been …

Evaluation Of The Effects Of Dynamic Excitation Characteristics On Ambient Vibration Test Results For A Multi-Girder Bridge, Gibran Santana

Civil Engineering Undergraduate Honors Theses

The bridge population in the US is currently aging and deteriorating rapidly. More than 30% of the bridges across the country have already exceeded their expected design life. Therefore, it is important to develop more timely, reliable and quantitative alternatives to the qualitative visual inspection approach that is currently used to evaluate these structures. One experimental approach that has been researched extensively for quantitatively characterize bridges is Ambient Vibration Testing (AVT) also known as Operational Modal Analysis (OMA). In this approach, the vibration responses of a structure due to unmeasured and uncontrolled ambient dynamic excitation are measured and analyzed to …

Temperature Sensitivity Of Foamed Warm Mix Asphalt, Ryan Michael Hagedorn

Civil Engineering Undergraduate Honors Theses

Foamed warm mix asphalt (WMA) is a technology that is beginning to be utilized across the United States. Often, producers are placing foamed WMA at decreased temperatures without fully understanding the properties of this relatively new product. By studying the volumetric properties of laboratory produced foamed WMA, this study sought to better understand the temperature sensitivity of foamed WMA and the potential factors that contribute to this sensitivity. Two mix designs containing primarily limestone aggregate were tested using differing binder grades. It was determined that binder grade, binder source and potentially the inclusion of recycled asphalt pavement all influence how …

Examination Of Nitrogen To Phosphorus Ratio In Nutrient Removal From Wastewater Through Chlorella Vulgaris, Courtney L. Hill

Civil Engineering Undergraduate Honors Theses

A need for phosphorus removal is becoming increasingly evident as some wastewater treatment plants struggle to meet wastewater effluent nutrient requirements. High nutrient levels in wastewater effluents have also caused ongoing tension between the state of Oklahoma and Arkansas regarding the pollution of the Illinois River. This research seeks to establish the relationship between nitrogen to phosphorus ratio in wastewater and the level of nutrient reduction using Chlorella vulgaris. Seed cultures of Chlorella vulgaris were added into solutions with various ratios of nitrate to phosphate representative of treated domestic wastewater and the removal of nitrogen and phosphorus were measured in …

Shear Capacity Of Prestressed Lightweight Self-Consolidating Concrete, Micah Alan Wyssmann

Civil Engineering Undergraduate Honors Theses

In prestressed members, self-consolidating concrete (SCC) has in some cases exhibited lower shear capacity than conventional concrete, which has been attributed to decreased aggregate interlock. However, little data is currently available to assess whether use of lightweight aggregate in prestressed SCC beams has further impact on aggregate interlock and shear strength. This study measured the shear capacity of six prestressed beams made from three different concrete mixtures: lightweight self-consolidating concrete (LWSCC) with expanded shale aggregate, LWSCC with expanded clay aggregate, and control normal weight SCC with limestone aggregate. Predicted shear capacities were determined based on current ACI Building Code and …

One-Dimensional Compressibility Of Intermediate Non-Plastic Soil Mixtures, Sean E. Salazar

Civil Engineering Undergraduate Honors Theses

The results of high stress, one-dimensional compression testing on intermediate soils are presented. Nevada Sand and silica silt mixtures were subjected to very high vertical stresses (140 MPa) in one-dimensional, monotonic compression. Each soil mixture was tested in a nominally loose condition. A specially designed mold with an integrated sensor array was fabricated to contain the soil during pre-consolidation and loading. The 1-D compression curve was plotted for each mixture in the double-logarithmic void ratio (e), and vertical effective stress (σ’v) space and characteristics of the Limiting Compression Curve (LCC) were identified. Initial and post test grain size distribution curves …

Effect Of Lightweight Aggregate Moisture Content On Internally Cured Concrete, Casey Jones

Graduate Theses and Dissertations

Putting an end to the rapid deterioration of concrete structures in the United States will only occur through the introduction of better materials and construction methods. The American Society of Civil Engineers (ASCE) reports the overall condition of concrete bridges in the United States to be a "C+". Though better than other areas of the infrastructure, there is still room for improvement in concrete bridges. One major area that may be improved is that of the concrete bridge deck. The bridge deck is comprised of the actual driving surface. It is subject to many deterioration mechanisms including freeze/thaw cycles, de-icing …

Return To Traffic Of Full Depth Reclamation Pavements, Robert Benjamin Hill

Graduate Theses and Dissertations

Full-Depth Reclamation (FDR) is a cost-effective rehabilitation treatment for deteriorated pavements. However, when using asphalt emulsion based rehabilitation techniques one of the most challenging aspects of FDR is determining when traffic can be returned to the rehabilitated pavement surface. Since asphalt emulsion mixtures need ample time for curing, they cannot be sealed with a surface layer until the water has evaporated from the rehabilitated layer. It is often not possible to keep the road closed until all of the water has evaporated and the surface layer is placed, therefore, at some point the traffic needs to be returned to the …

Full Depth Reclamation: Bringing Developing Countries' Transportation Up To Speed, Sadie Smith

Civil Engineering Undergraduate Honors Theses

Often, a direct correlation is observed between a country’s transportation network and economic development. Evidence of this is observed all over the world. Full Depth Reclamation (FDR) is a roadway recycling technique that mills and mixes the existing roadway with a stabilizing agent and then re-compacts the mixture to create a thicker, stabilized pavement layer. This method is both cost effective and environmentally friendly, making it a very appealing option as the need to rehabilitate or increase the structural capacity of existing roads grows. In this study, the material characterization of FDR was examined as a composite material of both …

Analysis Of Aggregate Distribution In Self-Consolidating Concrete, Brendan Ho

Civil Engineering Undergraduate Honors Theses

Concrete consists of several key ingredients: cement, water, and coarse and fine aggregate. Depending on the proportions of these ingredients, the strength and workability of a concrete mix can be affected adversely. Segregation is the separation of aggregate and cement paste, resulting in a lack of homogeneity. Self-consolidating concrete (SCC) does not require traditional consolidation; however, it can be affected by segregation. This project examines different SCC mixtures and establishes ranges of values for slump flow, T20 , Visual Stability Index (VSI), J-ring flow and J-ring flow spread that ensures proper aggregate distribution and therefore reduces the potential of segregation. …

Internal Curing Using Lightweight Fine Aggregate, Jonathan Kerby

Civil Engineering Undergraduate Honors Theses

Curing refers to the process of maintaining the hydration of the concrete as it hardens, or sets up. Concrete is cured to prevent things such as cracking and shrinkage. Autogenous shrinkage occurs internally in concrete because there isn’t enough water in the concrete for hydration, so the concrete rapidly draws out water to complete the hydration cycle, causing internal drying of concrete. There are two types of curing: external and internal. External curing utilizes water from external sources such as saturated burlap mats, ponding, or fogging. Internal curing supplies water from an internal source inside the concrete, such as saturated …

Performance And Cost Analysis Of A Structured Concrete Thermocline Thermal Energy Storage System, Matt Nicholas Strasser

Graduate Theses and Dissertations

Increasing global energy demands and diminishing fossil fuel resources have raised increased interest in harvesting renewable energy resources. Solar energy is a promising candidate, as sufficient irradiance is incident to the Earth to supply the energy demands of all of its inhabitants. At the utility scale, concentrating solar power (CSP) plants provide the most cost-efficient method of harnessing solar energy for conversion to electrical energy. A major roadblock to the large-scale implementation of CSP plants is the lack of thermal energy storage (TES) that would allow the continued production of electricity during the absence of constant irradiance. Sensible heat TES …

The Effect Of Mortar Strength On The Standard Test For Strand Bond, Cameron Murray

Civil Engineering Undergraduate Honors Theses

The prestressed industry is moving towards adopting the Standard Test for Strand Bond (STSB) to quantify the bond capacity of prestressing strand. In the test, strand is pulled through an 18 in. cylindrical casing filled with mortar. The force corresponding to the dead end displacement of 0.1 in. is recorded and this value is used to quantify strand bond. One of the concerns of the test is the requirement of a mean mortar strength of 4,500 to 5,000 psi during testing. There is concern that this 500 psi range may be too difficult to achieve. A study was conducted to …

The Effects Of Temperature On Indicator Species Tests For Water Quality, Maranda Guinn

Civil Engineering Undergraduate Honors Theses

This study sought to investigate the different response of two indicator species tests: Hach® PathoScreenâ„¢ Field Test and IDEXX Colilert® using the Quanti-Tray/2000® enumeration method. Both tests were carried out according to the instructions enclosed in the packages using diluted water samples taken from the secondary clarifier at the West Side Waste Water Treatment Plant in Fayetteville, AR. The tests were carried out at various temperatures in an attempt to reflect conditions that could be encountered in the field, where electricity, equipment, and expertise may not be available. The PathoScreenâ„¢ test responded adequately at a relatively wide range of temperatures, …

Risk Analysis And Reliability Improvement Of Mechanistic-Empirical Pavement Design, Xingqiang Danny Xiao

Graduate Theses and Dissertations

Reliability used in the Mechanistic Empirical Pavement Design Guide (MEPDG) is a congregated indicator defined as the probability that each of the key distress types and smoothness will be less than a selected critical level over the design period. For such a complex system as the MEPDG which does not have closed-form design equations, classic reliability methods are not applicable. A robust reliability analysis can rely on Monte Carlo Simulation (MCS). The ultimate goal of this study was to improve the reliability model of the MEPDG using surrogate modeling techniques and Monte Carlo simulation.

To achieve this goal, four tasks …

Effects Of Testing Time On Anaerobic Toxicity Assessment, Omolola Atinuke Akintomide

Graduate Theses and Dissertations

Anaerobic digestion has been widely used for wastewater treatment for decades. Several Anaerobic Toxicity tests have been developed to screen wastewater for toxicity and assess the treatability of such toxicants. However, past research and reviews on Biochemical Methane Potential (BMP) test and Anaerobic Toxicity Assay (ATA) were considered in this study.

The experimental tests included ammonium-nitrogen and sodium chloride toxicity tests with varied concentration and solid retention time. These tests were designed to demonstrate the impact of ammonia- nitrogen and sodium chloride on the biological degradation process. The anaerobic test set-up includes bench-scale test reactors and respirometers used for measuring …

The Development Of A High Performance Concrete To Store Thermal Energy For Concentrating Solar Power Plants, Emerson Esmond John

Graduate Theses and Dissertations

In recent years, due to rising energy costs as well as an increased awareness of the environmental effects of greenhouse gas emissions produced through traditional forms of energy production, there is great interest in developing alternative sources of energy. One of the most viable alternative energy sources is solar energy. In particular, concentrating solar power (CSP) technologies have been identified as an option for meeting utility needs in the U.S. Southwest. These systems are required to produce electricity not only during periods of high solar radiation but also during times of reduced radiation due to cloud cover, and even extend …

Investigating The Bond Of Prestressing Strands In Lightweight Self-Consolidating Concrete, Royce Woodrow Floyd

Graduate Theses and Dissertations

Lightweight self-consolidating concrete (LWSCC) is a relatively recent advancement in concrete technology. The reduced dead load from lightweight concrete is beneficial for precast elements and for elements where dead load is a significant portion of the total load, such as prestressed bridge girders. Self-consolidating concrete (SCC) is a specially proportioned concrete mixture that consolidates under its own weight without the need for vibration. The combination of lightweight concrete and self-consolidating behavior provides the benefits of both. Bond of prestressing steel has been a much debated topic since the 1950s. Limited data are available on the transfer and development length of …

New Insights Into Disinfection Byproduct Formation And Control: Assessing Dissolved Organic Matter Diffusivity And Chemical Functionality, Ashley Pifer

Graduate Theses and Dissertations

Methods were developed for application of asymmetric flow field-flow fractionation (AF4) and fluorescence parallel factor (PARAFAC) analysis to raw and treated samples from drinking water sources to improve characterizations of dissolved organic matter (DOM) and discover DOM properties correlated to disinfection byproduct (DBP) formation potential (FP). Raw water samples were collected from a reservoir, adjusted to pH 6, 7, and 8 and subjected to (1) jar tests using aluminum sulfate (alum) and (2) treatment with magnetic ion exchange (MIEX^®) resin. Both treatments were followed by DBPFP tests at pH 7. AF4 was used to size DOM in raw …

Wheel Path Wandering Based On Field Data, Wenting Luo

Graduate Theses and Dissertations

The position and width of wheel path on a pavement lane is an important consideration in conducting pavement distress survey, especially for distinguishing longitudinal cracking from fatigue cracking. Currently, the widely used wheel path definition is derived from the LTPP distress manual with fixed width and position, in which the influence of traffic wander on wheel path was overlooked. This thesis attempts to develop a new wheel path definition based on the lateral placement investigation of heavy vehicles' wandering in the field. Generally, the factors influencing vehicle lateral placement can be divided into seven categories, but only four factors are …

Efficacy Of Geosynthetic Separators And Filters: An Evaluation Of Test Sections In Marked Tree, Arkansas, Ashique Ali Boga

Graduate Theses and Dissertations

Field and laboratory tests were conducted on 18 full-scale, geosynthetic reinforced, roadway test sections located in Marked Tree, Arkansas. Base course, geosynthetic, and subgrade samples were collected, and pavement depth, in-situ density and in-situ hydraulic conductivity measurements were obtained during a geotechnical site investigation. The performance of sections containing geotextile products being used for separation and filtration (Carthage Mills FX-66, Mirafi 570, Propex 2006, Propex 2044, and Propex 4553) was investigated.

Moisture content, sieve analysis, Atterberg limits, modified proctor, specific gravity, and hydraulic conductivity tests were performed on the acquired soil samples. Transmissivity and permittivity testing was conducted on the …

Bond Performance Of Lightweight Self-Consolidating Concrete, Michael Howland

Civil Engineering Undergraduate Honors Theses

Self-consolidating concrete (SCC) allows for the placement of concrete without consolidation. The use of lightweight (LW) concrete reduces dead loads and lowers transportation costs. LWSCC is a recent combination of the two types of concrete; therefore there is little information on the performance of prestressed members cast with LWSCC. This project examines transfer length of LWSCC beams and compares the measured values to control-mixture members cast with normal weight SCC. Eight prestressed beams were cast. Of the eight, four conventional were cast with SCC and the remaining four with LWSCC. The lightweight mixtures contained expanded clay aggregate and had an …