Engineering Commons^™

Torsional Behavior Of Rc Beams Strengthened With Pbo-Frcm Composite, Meyyada Y. Alabdulhady

Doctoral Dissertations

"Externally bonded fiber reinforced cementitious matrix (FRCM) composites have been investigated recently as an alternative to fiber reinforced polymer (FRP) composites to overcome certain shortcomings such as the inability to install on wet surfaces or in low temperatures, low fire resistance, low glass transition temperature, low reversibility, and lack of vapor permeability. This study includes an inclusive investigation of the torsional behavior of RC beams strengthened with externally bonded polyparaphenylene benzo-bisoxazole (PBO)-FRCM composite material. A comprehensive review and discussion of the previous experimental, analytical, and numerically-simulated torsional behavior of RC beams strengthened with FRP composite was introduced to gain a …

Field Implementation Of Cement-Based Composite Strengthening Technologies, Michael Andrew Janke

Masters Theses

"With infrastructure continuing to age, technologies are being developed to strengthen structures as a more sustainable option than replacement. The use of fiber-reinforced cementitious matrix (FRCM) strengthening systems is a promising new technology for adding flexural and shear capacity to existing reinforced concrete members. While cement based systems with carbon, PBO, and steel have all been implemented in a lab setting, there is not research data available for installation in the field. FRCM composites have advantages over more widely used fiber reinforced polymer (FRP) composites such as heat resistance and compatibility with concrete substrate. FRP systems have previously been field …

Numerical Modeling Of Capillary-Driven Flow In Open Microchannels: An Implication Of Optimized Wicking Fabric Design, Mehrad Gholizadeh Ansari

Masters Theses

"The use of microfluidics to transfer fluids without applying any exterior energy source is a promising technology in different fields of science and engineering due to their compactness, simplicity and cost-effective design. In geotechnical engineering, to increase the soil's strength, hydrophilic wicking fibers as type of microfluidics have been employed to transport and drain water out of soil spontaneously by taking advantage of natural capillary force without using any pumps or other auxiliary devices. The objective of this study is to understand the scientific mechanisms of the capability for wicking fiber to drain both gravity and capillary water out of …

Dragline Excavation Simulation, Real-Time Terrain Recognition And Object Detection, Godfred Somua-Gyimah

Doctoral Dissertations

"The contribution of coal to global energy is expected to remain above 30% through 2030. Draglines are the preferred excavation equipment in most surface coal mines. Recently, studies toward dragline excavation efficiency have focused on two specific areas. The first area is dragline bucket studies, where the goal is to develop new designs which perform better than conventional buckets. Drawbacks in the current approach include operator inconsistencies and the inability to physically test every proposed design. Previous simulation models used Distinct Element Methods (DEM) but they over-predict excavation forces by 300% to 500%. In this study, a DEM-based simulation model …

Atomic Layer Deposition Prepared Nanostructured Materials For Various Catalytic Reactions, Xiaofeng Wang

Doctoral Dissertations

"Atomic layer deposition (ALD) has been widely used for thin film coating and metal nanoparticles (NPs) preparation. In this report, the applications of ALD prepared nanostructured materials in catalysis were examined.

Highly dispersed Pt monometallic catalysts with different substrates and multi-walled carbon nanotubes (MWCNTs) supported Pt-Co bimetallic catalysts were synthesized by ALD for selective hydrogenation of α, β-unsaturated aldehydes to unsaturated alcohols (UA). Pt/MWCNTs showed the highest selectivity of UA in selective hydrogenation of citral, as compared to Pt/SiO₂, Pt/ALD-Al₂O₃, and Pt/γ-Al₂O₃. After adding Co, the highest selectivity was achieved …

Shear Performance And Behavior Of Long Carbon Fiber Reinforced Concrete, Benjamin Paul Gliha

Doctoral Dissertations

”In this study, a laboratory testing program was developed to investigate the shear performance of fiber reinforced concrete beams. Long carbon fibers, to be included with a traditional fresh concrete mix, were developed and their shear performance was evaluated and compared to the performance and behavior of unreinforced concrete, traditionally reinforced concrete, and fiber reinforced concrete (FRC) with other fiber types.

The experimental program consisted of 30 large-scale beams tested for shear performance under monotonic loading. In addition to the large-scale beams, small-scale specimens were constructed of the same materials to correlate large-scale performances to ASTM C1609 testing and to …

Behavior And Temporal-Based Effects Of Sustainable Self-Consolidating Concrete In Bridge Structures, Hayder Hussein Alghazali

Doctoral Dissertations

"The main objective of this study was to investigate the performance of sustainable self-consolidating concrete (SCC) for highway bridge structures. Two types of concrete were utilized in this study: high volume fly ash-self consolidating concrete (HVFA-SCC) and high strength-self consolidating concrete (HS-SCC). This dissertation consists of two major parts: a laboratory study developing and investigating the overall performance of HVFA-SCC and a field study of time-dependent field-based behavior of HS-SCC in Bridge A7957 MO, USA. In the first part, an experimental program was conducted to develop a new class of SCC incorporating up to 70% cement replacement with fly ash. …

Strengthening Of Reinforced Masonry Walls Subjected To Out-Of-Plane Pseudo-Static Cyclic Load Using Advanced Composite, Zuhair Al-Jaberi

Doctoral Dissertations

"A number of researchers have conducted experimental tests on unreinforced masonry walls (URM) strengthened with advanced composite materials. Consequently, the strengthening design guidelines are limited in their scope to URM. This research aimed to investigate the behavior of reinforced masonry walls strengthened with advanced composite and subjected to out-of-plane pseudo-static cyclic load. Experimental and analytical studies were conducted to evaluate the performance of different techniques such as near surface mounted (NSM) and externally bonded (EB) fiber reinforced polymer (FRP) with epoxy resin, in addition to NSM with cementitious adhesive and fiber reinforced cementitious material (FRCM). The experimental part included three …

Service Response And Evaluation Of Prestressed Concrete Bridges Through Load Testing, Eli Saul Hernandez Ramos

Doctoral Dissertations

"During the last two decades, self-consolidating concrete (SCC) has emerged as an alternative to produce structures with longer life expectancy. Despite the advantages that come with using SCC, there are some concerns related to its structural and serviceability response. The effect of the larger paste content and smaller coarse aggregate size is of particular interest because this combination may inhibit the development of the SCC's target mechanical properties. Field tests are an effective method to monitor the service response of infrastructure. In addition, field tests have largely confirmed reserves of strength capacity in existing bridges despite their visual condition and …

Guayule Plant Extracts As Binder Modifiers In Flexible (Asphalt) Pavement Mixtures, Steven Michael Lusher

Doctoral Dissertations

"The guayule (pronounced, 'why-YOO-lee') plant is a woody perennial shrub that is native to areas of the southwestern United States and northern Mexico, and is a well-documented source of high-quality natural rubber. The U.S. needs a domestic source of natural rubber to allay concerns about its future availability. Cultivation of guayule in North America has been attempted many times since the late 19th century, and companies, including major tire manufacturers, are again investing in guayule research. However, full-scale commercialization of guayule rubber needs established markets for the two basic by-products of guayule rubber extraction: the plant resins (primarily non-rubber compounds) …

Multi-Scale Investigation Of Microstructure, Fiber-Matrix Bond, And Mechanical Properties Of Ultra-High Performance Concrete, Zemei Wu

Doctoral Dissertations

"The main objective of this study is to provide new insights into enhancing fiber-matrix bond and mechanical properties of ultra-high performance concrete (UHPC). Three main strategies were investigated: 1) use of supplementary cementitious materials; 2) use of nano-particles; and 3) use of deformed fibers. A multi-scale investigation involving the evaluation of non-fibrous UHPC mortar phase (matrix), fiber-matrix interface phase, and then UHPC composite material was undertaken to determine microstructural characteristics, fiber bond to matrix, and key mechanical properties of the UHPC matrix and UHPC. Test results indicate that the incorporation of 10%-20% silica fume effectively improved the fiber-matrix bond and …

Sensitivity Of Rheological Properties Of Cement Paste With Scc Consistency, Azadehalsadat A. Asghari

Doctoral Dissertations

"Robustness, which is defined as the capacity of a mixture to tolerate small variations in constituent elements, mixing parameters or temperature that are inevitable with production at any significant scale, is a key property to expand the practical implementation of self-consolidating concrete (SCC). At the first step, the effect of different amount of water, amount of superplastizer, mixing time, mixing speed and the addition time of superplastizer on the rheological properties of cement pastes with SCC consistency, has been evaluated. Two different SCC mix design concepts, the powder-type and VMA-type were selected for this research. The results show that the …

Bio-Inspired Geomaterial Improvement And Development Of Innovative Characterization Methods, Junnan Cao

Doctoral Dissertations

"This study experimentally investigated the bio-inspired improvement on geomaterials, including enzyme induced calcite precipitation (EICP) and biopolymers. This study also developed several innovative characterization tools to advance the state-of-the-art testing techniques, including SIP-BE column, rotational sedimental panel, and backpressure saturated constant hydraulic gradient break through column. Firstly, EICP test was performed on Ottawa 50-70 sand in a newly developed SIP-BE column. Nondestructive techniques -- spectral induced polarization (SIP) and bender element were used to monitor the precipitation process and shear wave velocities (V_s). SIP, V_s, and SEM results all suggest contact cementation as the preferential precipitation …

Adaptive Data Analysis For Damage Detection And System Identification In Civil Infrastructure, Hongya Qu

Doctoral Dissertations

"Time-varying structural systems are often encountered in civil engineering. As extreme events occur more frequently and severely in recent years, more structures are loaded beyond their elastic conditions and may thus experience damage in the years to come. Even if structures remain elastic, energy dissipation devices installed on structures often reveal hysteretic behaviors under earthquake loads. Therefore, it is imperative to develop and implement novel technologies that enable the identification and damage detection of time-varying systems. In this dissertation, adaptive wavelet transform (AWT) and multiple analytical mode decomposition (M-AMD) are proposed and applied to identify system properties and detect damage …

Critical Buckling And Post-Buckling Behavior Of Thin-Walled Liners Encased By Underground Pipelines In Saturated Soils, Zhaochao Li

Doctoral Dissertations

"This study aims to investigate the structural stability of thin-walled liners encased in functionally-obsolete underground pipelines in saturated soil under external hydrostatic pressure, a concentrated load, temperature change or their combination, and develop a simplified circular arch model of thin-walled liners when not constrained by the pipelines. The friction and adhesion on the interface between a liner and its constraining surface (pipeline or grouting), and the pressure gradient on deeply-buried pipelines are neglected. The critical buckling load of elastic liners is analytically derived under a plane strain condition using the principle of minimum potential energy. The analytical solution is either …

Long-Term Behavior Of Fiber Reinforced Polymer (Frp) Confined Concrete Cylinders Subjected To Severe Weather And Seawater Solution Conditions, Song Wang

Doctoral Dissertations

"This study presents an experimental investigation on durability of fiber-reinforced polymer (FRP) confined concrete cylinders subjected to various environmental conditions. Two types of cylinders were tested in this experiment: concrete-filled FRP tube (CFFT) and hollow-core FRP-concrete-steel (HC-FCS), with FRP tubes having two different constitutive resin components: polyester and epoxy. The specimens were subjected to three different environmental conditions: combined freeze/thaw, wet/dry and heating/cooling cycles with options of continuous water immersion and sustained axial load in an environmental chamber, UV exposure in an UV chamber, and seawater immersion in water tanks with sustained axial load. Mechanical and material characterization tests were …

Quantitative Phase-Field Modeling Of Crack Propagation In Multi-Phase Materials, Arezoo Emdadi

Doctoral Dissertations

”Research presented in this dissertation is focused on developing and validating a computational framework for study of crack propagation in polycrystalline composite ceramics capable of designing micro-architectures of phases to improve fracture toughness and damage tolerance of ZrB₂-based ultra-high temperature ceramics (UHTCs). A quantitative phase-field model based on the regularized formulation of Griffith’s theory is presented for crack propagation in homogenous and heterogeneous brittle materials. This model utilizes correction parameters in the total free energy functional and mechanical equilibrium equation within the crack diffusive area to ensure that the maximum stress in front of the crack tip is …

Examination Of Shear Friction Design Provisions, Nikkolas J. Edgmond

Masters Theses

"This thesis reports the results of research conducted to establish a state-of-the-art database of shear-friction studies to be turned over to ACI Committee 445-0D as a living document, utilize a subset of the established database to examine the effectiveness of the ACI 318 Code (2014), PCI Design Handbook (2010), AASHTO LRFD Bridge Design Specification (2016) and CSA A23.3 Design of Concrete Structures Standard (2014) provisions to predict shear transfer strength, and examine the effective coefficient of friction (µ_e) approach allowed in the PCI Design Handbook (2010).The shear friction design concept is applicable in conditions where direct shear must …

Bioaccessibility Of Lead From Contaminated Soil Using Phosphate Treatment -- Physiologically Based Extraction Test And In Vitro Gastrointestinal Method Test, Austin Charles Doss

Masters Theses

"Phosphate treatments are used to immobilize lead in soil by forming pyromorphite. Soil from Bonne Terre, Mo was collected to study whether such treatment decreases the bioaccessibility of lead. The soil was treated using 0.5 soil wt% of phosphate. Treatments were: none, phosphoric acid, triple super phosphate, and organic bone meal. Each sample was studied after one, four, sixteen, and twenty weeks; during this time span, water was added approximating the average rainfall rate. Percolated water was collected to test the leached phosphate concentrations. Phosphate was below the detection limit in that leachate. Remediated soil samples were used in Physiologically …

Simultaneous Enhancement Of Fluidity And Thixotropy Of Vibration-Free Concrete, Piyush Rajendra Lunkad

Masters Theses

"This research articulates the development of a vibration-free concrete for slip-form paving enabling a simple and rapid construction process. To achieve this, properties such as rheology including thixotropy, shape stability, and workability loss with time are mainly investigated. Concrete mixture with high thixotropic strength and its shape holding ability, flowability, and workability retention with time is evaluated. This study consists of two phases: (1) selection of paste component from rheology of cement paste incorporating various micro- and nano- sized particles (2) study of fresh properties of concrete mixtures using the excess paste layer concept.

From the cement paste study, it …

Nonlinear Finite Element Analysis Of Concrete Columns Subjected To Complex Loading, Adam Christopher Morgan

Masters Theses

"This study details the development and implementation of a finite element model within a commercial finite element code, Abaqus CAE, for the analysis of reinforced concrete (RC) bridge columns containing interlocking spirals subjected to combined loading conditions including axial, shear, bending, and torsional loads, including the post-peak response. The model is a first of its kind attempt at simulating the response of RC columns with continuous spiral transverse reinforcement and subjected to combined loading conditions including torsion. The model is utilized to determine the quasi-static load-deformation response under various proportions of the input loads and displacements. The resulting quasi-static load-deformations, …

Cellulose And Sulfate Degradation In A Biochemical Reactor During Treatment Of Mine Drainage, Sweta Ojha

Masters Theses

"Seventy-two biochemical reactors were set up, and operated using a mixture of chip-bark, horse manure, and gravel as the biochemical treatment substrate. The simulated mine water containing sulfate (1000 mg/l) was pumped into each reactor at a flow rate of 0.5 ml/minute (approximate), giving an empty bed contact time of 8 days. The main idea is that the microorganisms present in horse manure would convert the cellulose in chip-bark into volatile fatty acids. The produced volatile fatty acid would enhance the metabolism of sulfate-reducing bacteria (SRB) initially present in horse manure, which would degrade (and eventually remove) the sulfate from …

Compressive Behavior Of Masonry Columns Confined With Steel Reinforced Grout (Srg) Composite, Sarah Elizabeth Jemison

Masters Theses

"In this study, a new type of composite comprised of steel fiber cords embedded in a natural hydraulic lime mortar matrix, known as steel reinforced grout (SRG), is explored for the use in confinement of masonry columns. An experimental study was carried out to understand the behavior of solid clay brick masonry columns confined by SRG jackets. Twenty-four confined and seven unconfined columns with a square cross-section were tested to failure under a monotonic concentric compressive load. Test parameters considered were the column corner condition, number of fiber jacket layers, and number of fiber overlapping faces. SRG confinement improved the …

Imaging The Subsurface In Eastern Part Of Lake Chesterfield Using A Combination Of Geophysical Tools, Jiawei Li

Masters Theses

"The Lake Chesterfield North Dam in Wildwood city, Missouri has been leaking, more or less continuously since the dam was constructed in 1986 despite mitigation efforts in 1988, 1994, 1995, 2004, and 2005. Neither the grouting efforts in 1988, 1994, 1995, 2004 or 2005, nor the placement and rehabilitation of an impervious clay liner in 2005 has solved the problem. Indeed, in June of 2017, the water level in Lake Chesterfield dropped at an alarmingly rapid rate.

Prior to authorizing additional mitigation work, the Lake Chesterfield Home Owners Association (LCHOA) decided to acquire geophysical data across the dry lake bed. …

Cyclic Axial Compression Behavior Of Concrete-Filled Hybrid Large Rupture Strain Frp Tubes, Monika Nain

Masters Theses

"This study introduces an experimental investigation of the behavior of concrete filled fiber reinforced polymer (FRP) tubes (CFFTs) under cyclic axial compression. The FRP used in this study were either small rupture strain FRP (SRS-FRP) or large rupture strain FRP (LRS-FRP). This paper also presents the first-ever experimental study on the behavior of concrete confined using hybrid LRS-FRP and SRS-FRP. LRS-FRP included PEN (polyethylene napthalate) and PET (polyethylene terephthalate) where both of them having ultimate axial strain larger than 5%, and low stiffness. SRP-FRP included carbon and glass FRP having small rupture strains, smaller than 2%, and high stiffness. The …

Numerical And Experimental Analysis Of Local Buckling Of Axially Loaded Steel Tubes Confined By Concrete And Frp, Nicholas Colbert

Masters Theses

“The hollow core Fiber-Reinforced-Polymer (FRP) concrete circular-steel (HC-FCS) column consists of an outer circular fiber reinforced polymer (FRP) tube, an inner thin-walled circular steel tube concentrically aligned, and a concrete shell between them. Research has been performed on the performance of the member as a whole, but to date, there has been no investigation into the behavior of the steel tube confined in the column. 17 small-scale columns were tested under axisymmetric axial compressions applied directly to the steel tube under displacement control. The conducted parametric study examined the effects of diameter-to-thickness (D/t) ratio, concrete unconfined compressive strength, FRP thickness, …

Thermal Curing Efficiency Of Geopolymer Mortars, Simon Peter Sargon

Masters Theses

”Missouri is the fourth largest coal consumer in the U.S. with coal-fired power plants generate 81.3% of the electricity in the state which generate about 2.7 million tons of coal combustion residuals (CCRs) annually. The CCR, including fly ash, disposal issue is not limited to Missouri, rather it is a national issue with CCRs being the second largest waste stream in the U.S. Ninety million tons of fly ash are stored in landfills and ash ponds annually. Hence, using this waste product effectively is necessary. One of the emerging applications of fly ash is to use it as binder in …