Civil Engineering Commons^™

Corrosion Of Post-Tensioned Tendons Repaired With Dissimilar Grout, Juan Carlos Rafols

UNF Graduate Theses and Dissertations

A failure associated with steel corrosion was identified in early 2011 in a bridge external post-tensioned tendon, approximately eight years after construction. Large voids in the grout and pockets of non-homogeneous material were identified. The non-homogeneous grout was characterized by high moisture content, and in most cases, the chloride content was lower than conservative threshold values. The non-homogeneous grout also had high pH and high content of sulfates (approximately in the range of 10,000-ppm). As a result, there was an interest in the study of possible corrosion development in repaired systems in which the affected tendons have been re-grouted with …

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 …

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 …

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 …

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 …

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. …

Bs News January/February

Building Services Engineering

No abstract provided.

The Performance And Modification Of Recycled Electronic Waste Plastics For The Improvement Of Asphalt Pavement Materials, Baron W. Colbert

Dissertations, Master's Theses and Master's Reports - Open

Bulk electric waste plastics were recycled and reduced in size into plastic chips before pulverization or cryogenic grinding into powders. Two major types of electronic waste plastics were used in this investigation: acrylonitrile butadiene styrene (ABS) and high impact polystyrene (HIPS). This research investigation utilized two approaches for incorporating electronic waste plastics into asphalt pavement materials. The first approach was blending and integrating recycled and processed electronic waste powders directly into asphalt mixtures and binders; and the second approach was to chemically treat recycled and processed electronic waste powders with hydro-peroxide before blending into asphalt mixtures and binders. The chemical …

The Quantification Of The Fly Ash Adsorption Capacity For The Purpose Of Characterization And Use In Concrete, Zeyad Tareq Ahmed

Dissertations, Master's Theses and Master's Reports - Open

Fly ash has been shown to be an effective replacement for portland cement in concrete mixtures. However, many fly ash materials contain unburned carbon from the combustion process. Unburned carbon in fly ash adsorbs air entraining admixtures (AEAs) reducing their effectiveness in providing a specified air void system in concrete materials. Measurement tools and methods for characterization of the adsorption properties of fly ash materials are necessary for beneficial use of fly ash materials in concrete. In this research, two methods were developed to measure and quantify the adsorption capacity AEAs on fly ash materials. The first method is the …

Modeling Large-Truck Involved Crashes: An Econometric Modeling Framework, Mouyid Islam

Open Access Theses & Dissertations

This research aims to analyze large-truck involved crashes (i.e., having a gross vehicle weight rating more than 10,000 pounds) through the application of advanced econometric modeling techniques--namely, random parameter models (i.e., tobit regression, mixed logit). To achieve this, various national and state specific data sets are analyzed with the goal to provide an improved understanding of the complex interactions of contributing factors (e.g., factors related to drivers and occupants, vehicle, and road-environment) influencing large-truck crashes. Additionally, the modeling techniques considered in this research account for possible unobserved effects related to the data. The aforementioned econometric techniques provide an analytical foundation …

Carrier Collaborative Networks: Hybrid Hub Location Algorithms, Satyen Suresh Awale

Open Access Theses & Dissertations

Within the context of the Logistics and supply chain and management, the Hybrid Hub and Spoke system has certain complexities regarding the selection of the hub location in the supply chain facility system. The performance and efficiency of the network route selection and hub location depends upon the percentage savings that has been made by choosing the appropriate location for the hub to maintain the efficient flow of the goods within the network. Hub location selection mostly depends on the profit margins shared by the carrier, supply and demand status of the facility and amount of flow of the goods …

Methodologies For The Analysis Of Checked Baggage Inspection Systems, Nela Blejcharova

Open Access Theses & Dissertations

To enhance the security of the aviation system it is necessary to have a Checked Baggage Inspection System (CBIS) that is effective (that is, the highest possible detection probability or minimum false clear probability) yet efficient (that is, minimize the false alarm probability that causes inconvenience to passengers).

The first objective of this thesis is to review passenger, carry-on and checked baggage inspection procedures at airports

The second objective of this thesis is to develop a methodology using the optimization approach to set the optimal values of the sensitivity of the screening devices to minimize the total cost of inspecting …

Comparison Study Between Fem And Sem For Wave Propagation Models Applied To Solids, Shaddy Roberto Castillo Ponton

Open Access Theses & Dissertations

Wave propagation is a field whose application has spread across many disciplines. In the field of structural engineering, wave propagation methods have focused their attention specifically in the area of structural health monitoring and active control of vibrations and noise. Likewise, the development of new methods and their application have been successful in the area of material science with a special emphasis on the field of structural integrity evaluation of anisotropic and inhomogeneous structures (laminated composite structures). The current available analysis tools are inadequate to handle the modeling of complex structures. One-dimensional wave propagation problems in solids are still a …

Vulnerability Of Intermodal Logistic Networks To Sea Port Disruption, Jana Cervinska

Open Access Theses & Dissertations

Maritime trade is the backbone of international trade, specifically seaports which provide the gateway for the shipping and receiving of all international goods. Any disruption in operation can trickle down the global supply chain increasing costs and delay delivery of supplies. Hence, the objective of this work is the formulation of optimization models to study the vulnerability of intercontinental ports. Experiments are applied to container transportation between U.S. and Europe. The work differentiates itself from previous studies in that we analyze the vulnerability of the sea ports and compare how the closing of some ports or liner shipping lanes influence/impact …

Systematic Approach To Evaluate Potential Park And Ride Facilities, Lorenzo Emanuel Cornejo

Open Access Theses & Dissertations

Park and Ride (P&R) facilities promote transit ridership by providing an attractive option to car drivers. They enable potential users to drive to their locations where they can park their cars and take transit services to complete their destinations.

Although the concept of P&R has been implemented in many cities in the United States and integrated with different transportation modes such as mass rapid transit (MRT), light rail transit (LRT), high occupancy vehicle (HOV), Bus Rapid Transit (BRT), among others, no systematic approach has been developed to assess the feasibility of a potential P&R facility. This thesis proposes a systematic …

Calibration Of Concrete Pavement Performance Models, Alejandra Gallegos

Open Access Theses & Dissertations

Pavement performance models exist in various forms to cater to the pavement management agencies' needs and resources. Well-calibrated models are needed to accurately predict future pavement conditions, and to forecast and prioritize confidently the future rehabilitation and maintenance expenditures. Statistical tools are commonly used to develop the performance models. These statistical models may be impractical or misleading if not constrained with experts' opinions. This paper presents a hybrid technique where statistical tools and expert knowledge are combined for the calibration of pavement performance models. This technique was validated using historical pavement condition data for continuously-reinforced-concrete pavements (CRCP) from the Texas …

Sustainable Disposal Of Brine, Bijoy Krishna Halder

Open Access Theses & Dissertations

To meet growing water demand, more water is being harvested from nontraditional sources like brackish water from deep underground aquifers. Since these sources contain salts, drinkable water is produced by separating salt and other minerals (TDS, Total Dissolved Solids) from water through a process commonly known as desalination. A typical desalination plant produces 50-60% potable water from brackish water and the remaining water (brine) is disposed in evaporation ponds or by injecting it below the ground surface. To maximize the limited water supply, inland desalination plants have developed technologies to reduce brine production commonly known as zero liquid discharge (ZLD) …

Analysis Of Isolated Traffic Signal Control Systems, Petr Malina

Open Access Theses & Dissertations

Intelligent Transportation Systems (ITS) are implemented for increase of efficiency and safety in transportation. This thesis focuses on the area of traffic signal timing operations which is one of ITS components. The first objective is to compare the Czech and the U.S. methods for isolated fixed time traffic signal control, using an intersection in El Paso, Texas, as the test site. The second objective of this thesis is to evaluate the U.S. actuated isolated timing plan and compare it against the Czech and U.S. fixed time controls. A microscopic traffic simulation model of the selected intersection is coded in VISSIM …

Development Of Models To Estimate Modulus And Permanent Deformation Of Texas Bases, Eric Navarro

Open Access Theses & Dissertations

No