Digital Commons Network^™

Effect Of Side Edge Distance And Concrete Materials On Corrosion In Precast Prestressed Concrete Panels, Dayi Zhang

Masters Theses

"This study involved the spalling problem found in some partial-depth precast prestressed bridge decks in the state of Missouri. Recently, panels of several bridges have exhibited corrosion of the prestressing steel tendons causing concrete spalling at the edges of panels. Some of the exposed tendons are corroded to the point of rupture. The effect of factors, namely concrete side edge distance and concrete material type, on steel corrosion in chloride-contaminated reinforced concrete was investigated in this study. Wet-dry cycle tests and accelerated corrosion tests were carried out on sixty-three specimens designed with three different side edge distances and three different …

Energy Efficiency In Wastewater Treatment: Standards For Missouri Facilities, Samantha Lauren Markus

Masters Theses

"Traditionally, energy has been used to treat wastewater. As energy costs rise, so does the financial burden on communities with municipal wastewater treatment plants (WWTP). Determining energy efficiency of small to mid-sized plants is difficult because these plants are the least likely to have the resources to conduct an energy audit and the most likely to be overlooked in national models due to their small contribution to the national energy burden. Data was gathered via personal contact the WWTPs in Missouri and from this data metrics fro comparison were developed. The data was also compared to the predicted energy use …

Hardened Mechanical Properties And Durability Performance Of Specialized Concretes, Kyle Richard Holman

Masters Theses

"Concrete is one of the most produced and utilized materials in the world. Due to the labor intensive and time consuming nature of concrete construction, new and innovative concrete mixes are being explored. Self-consolidating concrete (SCC) is one such method of improving the overall cost and time efficiency of concrete production. SCC is a highly flowable form of concrete. This characteristic drastically reduces the amount of labor and time needed to place the concrete. The highly flowable nature also allows for much easier placement in applications of highly congested reinforcement.

Another rising concern in today's construction industry is environmental responsibility. …

Self-Consolidating Concrete For Infrastructure Elements Shear Characteristics, Eric B. Sells

Masters Theses

"Because of its unique ability to maintain high flow-ability and remain homogeneous, self-consolidating concrete (SCC) has the potential to significantly reduce the costs associated with civil infrastructure; however, the use of higher paste and lower coarse aggregate volumes than non-SCC concretes raises concerns about shear strength of SCC mixes. This research focused on the components that contribute to the concrete's ability to provide shear by aggregate interlock. Variables investigated by push-off tests included concrete compressive strength, coarse aggregate type , and volumetric content level of the coarse aggregate portion . Post-failure digital imaging software was used to confirm fresh concrete …

Driver Mandatory Lane Change Behavior: Use Of Governing Gap In Critical Gap Estimation, Srinadh Kandada

Masters Theses

"This study analyzed the driver gap acceptance and rejection behavior during mandatory lane changes on a multilane freeway in congested and uncongested traffic conditions. During a lane change, drivers were more receptive to either the leading or the trailing gaps with vehicles in the target lane which governed the drivers' lane change and is termed as the governing gap. Drivers maneuvered till the governing gap was greater than the critical gap, accepted the gap and made a lane change. In this process, drivers reduced the non-governing gap to increase the length of the governing gap. The drivers as a result …

Trace Element Accumulation In Rice :Effects Of Soil Arsenic, Irrigation Management, Phosphate Application And Iron Oxide Amendment, Eric Michael Farrow

Masters Theses

A concern is growing over the accumulation of trace contaminants in rice, a plant which has been estimated to supply 50% of the caloric intake to the world's population. Contamination with arsenic (As) and other trace elements have been shown in many areas including the U.S. and rice intake poses a potential risk to human health. This research investigated the accumulation of selected trace elements including arsenic (As), selenium (Se), molybdenum (Mo) and cadmium (Cd) in as many as six rice cultivars and two control soils common to the south central U.S. A field study was completed to evaluate the …

In Planta Solid Phase Sampling Devices Used In Delineating Groundwater Contaminant Plumes, Mikhil Kishore Shetty

Masters Theses

"The widespread and indiscriminate use of chlorinated volatile organic compounds as cleaning agents at dry - cleaning facilities, as metal degreasers and solvents in extraction and removal operations has been well documented in the past resulting in releases, while contaminating soil and groundwater. Current techniques to assess chlorinated solvents such as tetrachloroethylene (PCE) and trichloroethylene (TCE) in the subsurface have been time and cost intensive and more importantly invasive to the surrounding environment. New methods use trees as sources of information to access contaminant plume size and plume delineation. The major goal of these research studies has been to save …

Use Of High Volume Fly Ash-Wood Fiber And Polyurea Layers For Blast Mitigation, Anthony Francis Wulfers

Masters Theses

"This project is a continuation of research done by Natalia Carey and John Myers. The first part of Natalia's research was to develop and characterize an e-glass discrete fiber-reinforced polyurea (DFRP) system for infrastructure applications. She then recommended two polyurea systems (A and B) be further examined. These polyurea systems were then applied to plain reinforced concrete and steel fiber reinforced concrete panels (SFRC). Carey found that the SFRC panels sustained less overall damage. For this project SFRC was used as the base layer in combination with the DFRP systems. In addition to the DFRP and SFRC a high-volume fly …

Analysis Of Passive Louver Shading Systems And Impact On Interior Environment, Cory Joseph Brennan

Masters Theses

An installed passive louver shading systems can affect the heating, cooling, and lighting loads of any building, by altering the amount of solar energy, in the form of light and heat, from entering. The benefits of a louver system are derived from the application of solar geometry incident on the site and the climate within the area. By optimizing a passive louver system's design parameters, a building can reduce the total annual energy consumption due to artificial heating, cooling loads and artificial lighting. This research has implemented simulation modeling software, Energy Plus, to predict the effect of passive louver shades …

Bond Behavior Of High-Volume Fly Ash And Self-Consolidating Concrete, Trevor Jay Looney

Masters Theses

"The main objective of this study was to determine the effect on bond performance of high-volume fly ash (HVFA) concrete and self-consolidating concrete (SCC). The HVFA concrete test program consisted of comparing the bond performance of two concrete mix designs with 70% cement replacement with Class C fly ash relative to a Missouri Department of Transportation (MoDOT) standard mix design. The SCC test program consisted of comparing the bond performance of normal and high strength SCC with their respective MoDOT standard mix designs.

Two test methods were used for bond strength comparisons. The first was a direct pull-out test based …

Investigation Of The Effects Of Shrinkage, Creep, And Abrasion On Self-Consolidating Concrete And High Volume Fly Ash Concrete For Use In Transportation Related Infrastructure, Brian Timothy Tucker

Masters Theses

"Concrete specimens were fabricated for shrinkage, creep, and abrasion resistance testing. Variations of self-consolidating concrete (SCC), high volume fly ash concrete (HVFA), and conventional concrete were studied. The results were compared to previous similar testing programs and used to determine the adequacy of the materials for use in practice. These two concrete variations offer significant benefits when used as replacements to conventional concrete. Because of the respective properties of both types of concrete, both economic and environmental benefits are achieved with the use of both. The lower labor costs of SCC and the lower material cost of HVFA lead to …

Transport Of A Methamphetamine Surrogate Through Painted Drywall And Accumulation In Insulation, Nishanthini Vijayakumar Shakila

Masters Theses

"Methamphetamine is a drug of abuse in the United States and it is frequently produced in residential "meth labs." During a specific cooking stage called "salting out", a high concentration of methamphetamine is released into the air and can accumulate on and within indoor surfaces. Even after remediation, methamphetamine and other chemicals can be released into the occupied space by diffusion and desorption from insulation and painted drywall. To better understand the emission characteristics of methamphetamine, the diffusion coefficient of n- isopropylbenzylamine (NIBA; an isomer and surrogate for methamphetamine) was measured in latex painted drywall. To quantify the diffusion coefficient, …

A Novel Membrane Bioreactor Configuration For Nitrogen Removal, Timothy Harrison Canter

Masters Theses

"Population growth in the U.S. and abroad has led to a need for increased treatment of wastewater to limit the effects of additional pollution loadings on bodies of water. Additionally, this need is complicated by limitation on energy inputs. The solution is treatment reactors that are robust, simple to operate, effective in treatment, and energy efficient. This research will compare a traditional membrane bioreactor configuration with a design meant to address these issues.

The proposed configuration used differences in hydraulic head to move liquor from a pre-anoxic zone to the aerobic zone and return a portion of it to the …

Effects Of High Volume Fly Ash And Powder Activators On Plastic And Hardened Concrete Properties, Drew Alexander Davis

Masters Theses

This study was performed to examine the effects of high volumes of Class C fly ash modified by powder activators upon the plastic and hardened properties of concrete. In a companion study, five Missouri area cements and five Class C fly ashes were examined for incompatibilities, with the most and least reactive combinations being scaled up to full scale concrete testing. Two baseline concrete mixtures were examined, the only difference in mixtures being the sources of portland cement and fly ash. Fly ash replacement was examined at 50% and 70% replacement (by total cementitious mass). Three powder activators were used …

Behavior Of Staged Externally Bonded Carbon Fiber Reinforced Polymer Sheets For Improved Ductility, Laura Marie Rathe

Masters Theses

"Fiber reinforced polymers (FRP) has become increasingly used for the retrofit of aging structures for increased lifespans and for the rapid repair of damaged structures. It has many advantageous such as ease in rapid installation, high strength-to-weight ratio, and corrosion resistance. The main disadvantage of the material is brittle behavior with little warning of impending failures. The main objective of this study is to develop a new system of FRP that exhibits a more ductile behavior. To achieve this objective, separate sheets of FRP were applied at various staged levels and thus engaged at different loads. Ductile behavior was evaluated …

Bond, Transfer Length, And Development Length Of Prestressing Strand In Self-Consolidating Concrete, Krista Beth Porterfield

Masters Theses

"Due to its economic advantages, the use of self-consolidating concrete (SCC) has increased rapidly in recent years. However, because SCC mixes typically have decreased amounts of coarse aggregate and high amounts of admixtures, industry members have expressed concerns that the bond of prestressing strand in SCC may be compromised. While the bond performance of prestressing strand in a new material such as SCC is an important topic requiring investigation, the results are only applicable if the research is completed on strands with similar bond quality as the strands used in the field. Therefore, the objectives of this research program were …

Depth Profiling Of Pahs Treated With Activated Carbon Using In-Situ Spme, Ryan D. Stringer

Masters Theses

"Novel and efficient methods to measure the bioavailability of hydrophobic organic contaminants (HOCs) in contaminated sediments will play an important role in the acceptance of alternative sediment remediation strategies. In this project, solid phase microextraction (SPME) fibers, protected in perforated steel tubes, were used as in situ passive samplers to measure the treatment of activated carbon (AC) in polycyclic aromatic hydrocarbon (PAH) contaminated sediment. Contaminated sediment was treated with two modes of AC waterjet amendment. In the first treatment, a single 2-min injection was shot into the center of a test vessel and in the second treatment, multiple 7-sec injections …

Blast And Impact Resistance Of "Long" Carbon Fiber Reinforced Concrete, Darwin Ishmael Keener

Masters Theses

"Traditional reinforced concrete is one of the most commonly used materials for protective structures. However, conventional reinforced concrete (RC) is susceptible to significant spalling (small to medium sized chunks of concrete detaching from the original member) during blast events. The force of the blast turns spalled concrete into projectiles, resulting in secondary fragmentation. Furthermore, the concrete debris makes for difficult and uncertain footing. Both phenomena endanger personnel and complicate post-blast recovery efforts. Changes need to be made to conventional reinforced concrete structures to improve their blast and impact survivability and fragmentation resistance in order to protect personnel and facilitate post-blast …

Effects Of High Volumes Of Fly Ash On Cement Paste, Karl Wehking Beckemeier

Masters Theses

"The study of high-volume fly ash (HVFA) concrete mixtures has become popular due to the significant environmental and economic benefits which the material may provide. By including fly ash at 50 percent or greater replacement levels, substantial benefits could be obtained. However, the inclusion of fly ash can have negative effects, including incompatibilities between constituents of a mixture. As the fly ash replacement level increases, the degree and likelihood of these problems increases.

In this study, paste mixtures were made, as part of a larger HVFA concrete study, in order to determine the degree to which varying levels of fly …