Engineering Commons^™

A Programmatic Approach To Long-Term Bridge Preventive Maintenance, Danny Wells, Bobby W. Meade, Theodore Hopwood Ii, Sudhir Palle

Kentucky Transportation Center Research Report

State transportation agencies use cost-effective preventive maintenance (PM) programs to preserve existing roadway systems, slow down their deterioration, and improve their functional condition. Currently, KYTC’s bridge inventory includes approximately 10,000 structures, and by 2018, most of these structures will have been in use for at least 50 years. Because there is insufficient funding available to pursue a large-scale bridge replacement program, it is critical for the Cabinet to prolong the lives of its bridges by using economical strategies. This report provides guidance that the Kentucky Transportation Cabinet (KYTC) can use to develop and implement a statewide bridge PM program. Drawing …

Design And Validation Of Novel Potential High Entropy Alloys, Boliang Zhang

LSU Doctoral Dissertations

The design approach and validation of single phase senary refractory high entropy alloys (HEAs) MoNbTaTiVW and HfNbTaTiVZr were presented in first part of this dissertation. The design approach was to combine phase diagram inspection of available binary and ternary systems and Calculation of Phase Diagrams (CALPHAD) prediction. Experiments using X-ray diffraction and scanning electron microscopy techniques verified single phase microstructure in body centered cubic lattice for both alloys. The observed elemental segregation agrees well with the solidification prediction using Scheil model. The lattice constant, density and microhardness were measured to be 0.3216 nm, 4.954 GPa and 11.70 g/cm³ for …

Evaluation Of Non-Chromate Passivations On Electroplated Γ-Phase Zinc Nickel, Steven Michael Volz

Masters Theses

"This research focused on the corrosion response and electrochemical behavior of electroplated low hydrogen embrittlement alkaline γ-phase zinc nickel with passivation layers. The motivation was the need to replace hexavalent chromium conversion coatings in military grade electrical systems with a more environment friendly alternative. The passivation layers were employed for the purpose of mitigating corrosion attack while maintaining low contact resistance. Trivalent chromium-based passivations and cerium-based passivations were compared against the currently used hexavalent chromium conversion coating. The coating systems were compared using electrochemical impedance spectroscopy, cyclic potentiodymanic scans, salt spray exposure testing, electrical resistance measurements, microstructure analysis, and compositional …

Development Of A Localized Electrochemical Properties Test Method： A Study Of Cocrmo And Ti Alloy Localized Electrochemical Behavior, Sile Hu

Theses - ALL

Abstract: Corrosion of metallic biomaterials in biomedically-relevant environments depends on the local physical and chemical structure of the metal surface at the metal-solution interface, and the geometry of the electrode system. Local surface structure, including defects, inclusions, and grain boundaries may locally alter the electrode behavior, while local geometries, including crevice-like geometries or small electrode areas will give rise to specific changes in electrochemical behavior. Methods to detect local defects or surface flaws electrochemically may be possible with the appropriate combination of microelectrodes and pipette geometries. In order to have a better understanding of the localized electrochemical behavior under given …

Development Of Multilayer Titanium Nitride-Based Coatings As Corrosion Resistant Films For Stainless Steel Bipolar Plates In Pem Fuel Cells, Nicholas Padula

Legacy Theses & Dissertations (2009 - 2024)

High cost and short lifetime are the two main reasons why the PEM fuel cell has not reached a widespread, disruptive level of commercialization. Conventional graphite bipolar plates are responsible for about 45% of the cost and 85% of the total weight of a single cell. These measures are linked to difficult machining of thick, brittle graphite and processing needed to render graphite non-porous. Stainless steel is suggested as the replacement bipolar plate material due to its favorable mechanical properties, ease of manufacturing and relatively low price, but requires a cost-effective coating as a non-conductive oxide forms on the bare …

The Effects Of Carboxylic Acids In Aluminum Anodizing, Abby E. Koczera

Honors Theses and Capstones

Hard-anodized alumina coatings were formed in sulfuric acid at low temperature and high current density in the presence of carboxylic acid additives. Citric acid, trimesic acid, mellitic acid and ethylenediaminetetraacetic acid (EDTA) were utilized in varying concentrations. The additives were chosen for their capacity to form complexes with tri-valent aluminum and hence impart chemical stability to the coatings. The coatings were sealed in boiling water, and corrosion resistance was observed in a high pH solution of potassium hydroxide. The coatings were examined using scanning electron microscopy (SEM) to assess coating thickness and pore dimensions. Thicker coatings were produced when the …

Effects Of Corrosion Inhibitor On The Corrosion Behavior Of Low Carbon Steel In Co2 Environment, Michael Harris

Williams Honors College, Honors Research Projects

The effectiveness of Benzalkonium chloride (C14) as a corrosion inhibitor for mild steel in an aqueous CO₂ environment was studied for dual use. It is a known biocide and currently untested corrosion inhibitor. Potentiodynamic polarization was used to determine the anodic and cathodic reaction kinetics through analysis of the potentiodynamic curves and the corrosion current densities. Electrochemical impedance spectroscopy (EIS) was utilized to analyze the surface characteristics through analysis of the Nyquist and Bode plots. C1010 and C1018 mild steel were tested in a 200mL jacketed Gamery cell, and purged with CO₂ (99.9%). Temperature effects were studied and …

Evaluation Of Epoxy Coatings For Protecting Aluminum Alloy 2024 From Corrosion Caused By Aspergillus Niger, Kamshat Dukenbaeva

Williams Honors College, Honors Research Projects

The aim of this study was to assess the potentials of using epoxy coatings for the prevention of fungus-induced corrosion. The metal specimen of interest was the aluminum alloy AA 2024-T3. The main intent was to evaluate the behavior of the organic acid producing fungus, Aspergillus niger (A. niger), towards the epoxy-coated aluminum. Two different types of epoxy coatings were used: a two-part resin and a commercially-available Rust-Oleum Specialty Appliance Epoxy. Due to challenges encountered throughout the length of the project and time constraints, limited quantitative data was obtained. However, from optical and visual data it can be concluded that …

Effect Of Sintering Temperature On Microstructure, Corrosion Behavior, And Hardness Of Nanocrystalline Al-5at.%Ni And Al-5at.%V Alloys, Matthew G. Wachowiak

Williams Honors College, Honors Research Projects

The purpose of this project was to investigate thermal stability of high energy ball milled Al-5at.%Ni and Al-5at.%V alloys. Characterization was done by analyzing grain size and solid solubility. Samples were created using high energy ball milling, cold compaction to 3 GPa, and sintering from 100 °C to 500 °C at 100 °C increments, as well 450 °C and 614 °C. Microstructure, mechanical properties, and corrosion properties were determined using scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, hardness testing, and cyclic potentiodynamic polarization. Vickers hardness of Al-5at.%Ni decreased with increasing temperature. For Al-at.%V, hardness increased with sintering temperature …

Pitting Corrosion Of 410 Stainless Steel In Hcl Solutions, Paul D. Krell

Williams Honors College, Honors Research Projects

410 stainless steel (SS) is a material used in HCl services, such as distillation column trays in oil refineries. Unlike other alloys, however, the oil refining industry lacks a good reference for the corrosion rate of 410 SS at the varying HCl concentrations and temperatures the material might experience as trays in crude unit distillation columns. The goal of this project is to fill that knowledge gap. The corrosion behavior of 410 SS in HCl environments of pH 0.50, 1.25, 2.25, 3.25, and 4.25 at temperatures of 38, 52, 79, and 93°C was investigated using several methods. Cyclic potentiodynamic polarization …

Corrosion Resistance Of Silane Coatings On Aluminum And Magnesium Alloys, John Demopoulos

Williams Honors College, Honors Research Projects

The purpose of this project was to increase the corrosion resistance of aluminum and magnesium alloys by coating the coupons with a silane on the surface. Four different silanes: 3-aminopropyltriethoxysilane (APTES), Bis(triethoxysilylpropyl)amine (Bis), (Heptadecafluoro-1,1,2,2-tetrahydrodecyl)trichlorosilane (FTS), and (Heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane (non Cl FTS) will be used and compared to see which silane would give the best corrosion resistance. Each silane solution was coated on the coupons by using a solution method in which the coupon was submerged for 24 hours and then thermally cured for another 24 hours. Once the coating was applied, the water contact angle and the thickness of the coating …

Bridge Maintenance To Enhance Corrosion Resistance And Performance Of Steel Girder Bridges, Luis M. Moran Yanez

Open Access Dissertations

The integrity and efficiency of any national highway system relies on the condition of the various components. Bridges are fundamental elements of a highway system, representing an important investment and a strategic link that facilitates the transport of persons and goods. The cost to rehabilitate or replace a highway bridge represents an important expenditure to the owner, who needs to evaluate the correct time to assume that cost. Among the several factors that affect the condition of steel highway bridges, corrosion is identified as the main problem. In the USA corrosion is the primary cause of structurally deficient steel bridges. …

The Economy Of Preventive Maintenance Of Concrete Bridges Due To Corrosion, Haotian Zhang

Dissertations - ALL

The current practice for physical evaluation and delayed maintenance of deteriorated concrete bridge is fundamentally wrong. This research presents a new approach for the evaluation of the condition states of steel reinforced concrete bridge members, which is based on their chemical conditions instead of the physical deficiencies such as cracks and delamination. Using the proposed chemical based inspection approach, a more effective and economic preventive maintenance plan could be achieved. The available non-destructive evaluation (NDE) methods and preventive maintenance measure are identified. Since the chloride induced corrosion is the major factor that dictates the service life of the steel reinforced …

Thin Film Concrete Coatings, Bobby W. Meade, Danny Wells, Theodore Hopwood Ii, Sudhir Palle

Kentucky Transportation Center Research Report

KTC researchers obtained eight types of concrete coatings to assess their performance and resistance to chloride penetration. Researchers evaluated eight of the systems in the field and seven in the laboratory. In the field, coatings were applied to a bridge pier that had suffered degradation and chloride contamination. This site will undergo long term monitoring in order to thoroughly evaluate the coating systems. Adhesion of all products in both field and laboratory application was sufficient to provide a durable coating, and ranged from approximately 500 psi to 1,600 psi. Researchers also tested color and gloss changes, which are early indicators …

Chloride Contamination Remediation On Steel Bridges, Bobby W. Meade, Christopher Goff, Sudhir Palle, Theodore Hopwood Ii

Kentucky Transportation Center Research Report

Researchers evaluated 32 steel surface preparation methods to determine how effectively they remove chloride from corroded chloride-contaminated steel panels. Wet methods proved more effective than dry methods. The three most effective wet methods injected mineral slag abrasives in a water stream and resulted in less than 1% chlorides remaining. Most dry surface preparation methods left significantly more chloride contamination after surface preparation. The three most effective dry methods used multiple blast cleaning cycles. These methods approached the effectiveness of the best wet methods, with 1.6 to 2.0% chlorides remaining. The least effective surface preparation was a single abrasive blast cleaning …

The Long-Term Performance Of Concrete Crack And Deck Surface Sealers, Emily A. Byl

Open Access Theses

Concrete bridge decks in the State of Indiana are undergoing continuous deterioration and loss of service life due to the use of deicing salts during winter weather conditions. As salt water penetrates the deck through cracks and the concrete surface, chlorides, water and oxygen are able to access the reinforcement to initiate corrosion. The corrosion of reinforcing steel over time creates an ongoing need for costly deck repairs and/or deck replacement. This study investigates the performance of crack sealers and deck surface sealers as a potentially cost-effective method of increasing bridge deck service life. An experimental program was developed and …

The Impact Of External And Self-Induced Magnetic Fields On The Development Of Corrosion On Ferous And Non-Ferrous Materials, Clint G. Gnegy-Davidson

Electrical Engineering Dissertations - Archive

As the US Navy continues to field ships with an increasing number of electrical generators and loads, it is unclear how the high magnetic fields being generated throughout the ship will affect the corrosion rate of the ships structural and high current conducting alloys. Given the high- pulsed current carried by pulsed power systems, it is of increased interest to understand what impact their deployment will have on metallic corrosion. In this work, a number of experiments have been designed and performed to study these phenomena. In the first set of experiments several alloys have been subjected to a continuous, …

Effect Of Severe Corrosion On Lateral Strength Of Square Rc Bridge Columns, Sara Sotoud

Dissertations - ALL

Corrosion of reinforcing steel bars is the primary durability problem that causes degradation of reinforced concrete structures located in aggressive environments. Severe corrosion of steel bars decreases the lateral load-carrying capacity of reinforced concrete members, causes loss in the mechanical properties of reinforcement and cross-sectional area of steel bars and concrete cover, bond deterioration, reduces anchorage of steel bars, and decreases the confinement by transverse reinforcement. Consequently, corrosion results in drop in the lateral strength of columns. Therefore, studying response of corroded reinforced concrete columns subjected to lateral loads is necessary.

According to the Federal Highway Administration (FHWA) report in …

Controlling The Corrosion And Cathodic Activation Of Magnesium Via Microalloying Additions Of Ge, R. L. Liu, M. F. Hurley, A. Kvryan, G. Williams, J. R. Scully, N. Birbilis

Materials Science and Engineering Faculty Publications and Presentations

The evolution of corrosion morphology and kinetics for magnesium (Mg) have been demonstrated to be influenced by cathodic activation, which implies that the rate of the cathodic partial reaction is enhanced as a result of anodic dissolution. This phenomenon was recently demonstrated to be moderated by the use of arsenic (As) alloying as a poison for the cathodic reaction, leading to significantly improved corrosion resistance. The pursuit of alternatives to toxic As is important as a means to imparting a technologically safe and effective corrosion control method for Mg (and its alloys). In this work, Mg was microalloyed with germanium …

Probability Model Of Corrosion-Induced Cracking Time In Chloride-Contaminated Reinforced Concrete, Chunhua Lu, Jinmu Yang, Ronggui Liu

International Conference on Durability of Concrete Structures

Corrosion-induced concrete cover cracking caused by chloride ion is an important indication of durability limit state for marine reinforced concrete (RC) structures and can ultimately determine the structural service life. In this paper, considering the random nature of factors affecting the corrosion cracking process, a probabilistic model which expands on the deterministic model of cover cracking time is developed by using Monte Carlo simulation technique. The results showed that the time to corrosion cracking can be modelled by the Weibull distribution. Finally, the probabilistic analysis for the cracking time is applied to an in-site RC bridge girder with four different …

An Experimental Study On Effect Of Steel Corrosion On The Bond–Slip Performance Of Reinforced Concrete, Xiaolin Zhang, Xuebing Liang, Hancheng Huang, Haijun Zhou

International Conference on Durability of Concrete Structures

This paper studied the effects of reinforcement corrosion on bond performance between rebar and concrete. Tests were carried out to evaluate the degradation of bond between reinforcing steel and concrete for different corrosion levels of reinforcing steel. A series of 20 specimens of different concrete strength with various reinforcing steel corrosion levels were designed and manufactured. Each specimen was casted as a 200-mm concrete cube, and a steel rebar was centrally embedded with two stirrups around it. The steel rebar were corroded using an electrochemical accelerated corrosion technique. The corrosion crack opening width and length were recorded after the corrosion …

Progress In Durability Study Of Frp Materials, Zeng-Zhu Zhu, Ying-Wu Zhou, Li-Li Sui, Feng Xing, Jia Du

International Conference on Durability of Concrete Structures

During the past decades, FRP strengthened RC structures have attracted worldwide interest in both application and research. Nowadays, as more and more infrastructures are being suffered from severe corrosions due to harsh and extreme environments, the durability of FRP strengthened RC structures has generally emerged as the most important issue in research. Thus, the paper presents the latest progress in durability study of the FRP materials through an in-depth review and analysis on existing extensive investigations. The time-dependent performances of two types of FRP materials of carbon FRP (CFRP) and glass FRP (GFRP) under severe environments of humidity, high temperature, …

Effect Of Pet Wrapping On Shear Performance Of Corroded Reinforced Concrete Columns, Dawei Zhang, Yuxi Zhao, Weiliang Jin, Tamon Ueda

International Conference on Durability of Concrete Structures

In this paper, an experimental study is presented on the influence of PET warping on shear performance, such as diagonal shear cracking load, peak load, and energy dissipation of RC columns with stirrup corrosion before strengthening. The experimental program involved an electrochemical process to accelerate the migration of chlorides from an external electrolyte into the tested columns, a wetting–drying cycle process with a controlled current to speed up the corrosion of the stirrup in the tested columns, the strengthening of corroded columns with PET warping, and a pseudostatic test to determine the shear capacity of the tested beams. The shear …

Corrosion Of Steel In Concrete And Its Prevention In Aggressive Chloride-Bearing Environments, Luca Bertolini, Maddalena Carsana, Matteo Gastaldi, Federica Lollini, Elena Redaelli

International Conference on Durability of Concrete Structures

This keynote paper deals with the durability of reinforced concrete (RC) structures exposed to aggressive environments characterized by high concentration of chloride ions, namely, marine environments or the use of de-icing salts. The mechanism of chloride-induced corrosion of steel in concrete is introduced, and its influence on the service life of RC structures is analyzed. Factors affecting the time to corrosion initiation are described with regard to both concrete properties and environmental exposure conditions. Design approaches available for achieving durability targets associated with the design service life are analyzed, focusing on studies carried out by the authors in recent years …

Eigenstress Model For Electrochemistry Of Solid Surfaces, Hongxin Ma, Xilin Xiong, Panpan Gao, Xi Li, Yu Yan, Alex A. Volinsky, Yanjing Su

Mechanical Engineering Faculty Publications

Thermodynamic analysis and molecular dynamics simulations were conducted to systematically study the size-dependent electrochemical response of solids. By combining the generalized Young-Laplace equation with the popular Butler-Volmer formulation, the direct influence of surface stress on solid film electrochemical reactions was isolated. A series of thermodynamic formulas were developed to describe the size-dependent electrochemical properties of the solid surface. These formulas include intrinsic surface elastic parameters, such as surface eigenstress and surface elastic modulus. Metallic films of Au, Pt, Ni, Cu and Fe were studied as examples. The anodic current density of the metal film increased, while the equilibrium potential decreased …

Material Weakening Due To Corrosion In Hardened Bearing Steels, R.H. Vegter, M. Ersson, Bo Han

International Workshop on the Environmental Damage in Structural Materials Under Static Load/Cyclic Loads at Ambient Temperatures

In rolling and ball bearings, materials are designed to withstand extremely high loads for long operation times. Most bearing steels are hardened steels with high carbon content that typically can function up to the Very High Cycle Fatigue regime (>1010 load cycles). The loads under which this occurs are given by the fatigue limit, which is a parameter that does depend on the strength of the material, but is commonly seen as a fixed parameter Therefore, material weakening is playing an important role when components fail as a result of rolling contact fatigue loading. In this paper, the effects …

Evaluation Of The Use Of Painted And Unpainted Weathering Steel On Bridges, Theodore Hopwood Ii, Sudhir Palle, Bobby W. Meade, Rick Younce

Kentucky Transportation Center Research Report

KTC researchers studied the use of unpainted weathering steel on bridges, using findings of inspections performed on Kentucky Transportation Cabinet (KYTC) bridges constructed with both painted and unpainted weathering steel as well as laboratory testing. Laboratory tests were conducted on test panels of conventional and weathering grades of steel to determine the performance of barrier and zinc-based coatings over abrasive-blasted substrates of those steel types in both the new and corroded conditions. The report provides the following recommendations for the use of painted and unpainted weathering steel on Kentucky bridges based upon both the field and laboratory findings:

• KYTC should …

Maximizing Use Of Air-Side Economization, Direct And Indirect Evaporative Cooling For Energy Efficient Data Centers, Betsegaw Kebede Gebrehiwot

Mechanical and Aerospace Engineering Dissertations - Archive

Data centers house information technology (IT) equipment such as servers and network switches which are vital for our networked modern society by providing digital data storage, data processing and connectivity. Data centers house few hundreds to tens of thousands of IT equipment that consume few kilowatt-hours to multi-megawatt-hours of electrical energy that gets dissipated as heat. IT equipment need to be properly cooled so that they operate reliably for their expected lifetime. For air cooled IT equipment, manufacturers provide heat sinks, cold plates, fans, et cetera to remove heat from the vicinity of heat dissipating components and data centers need …

A Study Of Electrical Double Layer Structure Over A Corroding Steel Surface In Sea Water, Pratik Babanrao Kale

Mechanical and Aerospace Engineering Theses - Archive

Corrosion is a natural deterioration phenomenon that throws profound adverse effects on the performance of structural steel in marine applications. Seawater consists of various corrosive components such as chlorine ions, sulphate ions and many more. These chemical components are mainly responsible for the corrosion phenomenon. Even though their bulk concentrations are known, their local concentrations and distribution in the vicinity of a steel surface where the corrosion occurs are yet unclear. Without the knowledge, would any approach to deal with the corrosion be empirical, at best. The main objective of the present thesis is to investigate the interfacial structure of …

Analysis Of Electric Double Layer Structure Formed During Corrosion Of Steel Pipes Carrying Potable Water, Tanmay Sanjeev Gupte

Mechanical and Aerospace Engineering Theses - Archive

Corrosion of steel pipes carrying drinking water is a universal issue. It affects human health as the corrosion sediments in these pipes can be toxic and unfit for consumption. Further, the amassing of the corrosion products can lead to operational difficulties. Drinking water consists of anions like carbonate, hydroxides and chloride ions which are responsible for the corrosion process. In such types of aqueous corrosion, there is an interfacial region formed between the corroding metal and the bulk of the aqueous environment. This interfacial region is called the Electrical Double Layer. In this article, we direct to study the effects …