Engineering Commons^™

Periodic Deprivation Of Gaseous Hydrogen Sulfide Affects The Activity Of The Concrete Corrosion Layer In Sewers, Xiaoyan Sun, Guangming Jiang, Philip Bond, Jurg Keller

Faculty of Engineering and Information Sciences - Papers: Part B

Sulfide induced concrete corrosion significantly reduces the service life of the sewer systems. Gaseoushydrogen sulfide (H2S) levels are a key factor affecting the corrosion rate and thesefluctuate due to thediurnalflow pattern of sewers. Currently, there is little known about how suchfluctuations, in particularthe periodic deprivation of H2S, may affect the corrosion activity. This study investigated the impact ofthe deprivation of H2S on the sulfide uptake rate (SUR) of concrete coupons incubated in laboratorycorrosion chambers. After systematic evaluation of the gaseous H2S concentration profiles of two sewersystems, two types of profiles, i.e. short- (1 h) and long- (12 h) term deprivation …

The Rapid Chemically Induced Corrosion Of Concrete Sewers At High H2s Concentration, Xuan Li, Liza O'Moore, Yarong Song, Philp Bond, Zhiguo Yuan, Simeon Wilkie, Lucija Hanzic, Guangming Jiang

Faculty of Engineering and Information Sciences - Papers: Part B

Concrete corrosion in sewers is primarily caused by H2S in sewer atmosphere. H2S concentration can vary from several ppm to hundreds of ppm in real sewers. Our understanding of sewer corrosion has increased dramatically in recent years, however, there is limited knowledge of the concrete corrosion at high H2S levels. This study examined the corrosion development in sewers with high H2S concentrations. Fresh concrete coupons, manufactured according to sewer pipe standards, were exposed to corrosive conditions in a pilot-scale gravity sewer system with gaseous H2S at 1100 ± 100 ppm. The corrosion process was continuously monitored by measuring the surface …

Toward Improving Ambient Volta Potential Measurements With Skpfm For Corrosion Studies, Corey M. Efaw, Thiago Da Silva, Paul H. Davis, Lan Li, Elton Graugnard, Michael F. Hurley

Materials Science and Engineering Faculty Publications and Presentations

Scanning Kelvin probe force microscopy (SKPFM) is used in corrosion studies to quantify the relative nobility of different microstructural features present within complex metallic systems and thereby elucidate possible corrosion initiation sites. However, Volta potential differences (VPDs) measured via SKPFM in the literature for metal alloys exhibit large variability, making interpretation and application for corrosion studies difficult. We have developed an improved method for referencing SKPFM VPDs by quantifying the closely related work function of the probe relative to an inert gold standard whose modified work function is calculated via density functional theory (DFT). By measuring and tracking changes in …

Controlled Release Of Corrosion Inhibitors: Zinc And Magnesium Containing Sodium Chromate, Andrew Thomas

Williams Honors College, Honors Research Projects

Corrosion can be combated by multiple methods, where the primary purpose is to minimize degradation of metal surfaces. Corrosion inhibitors are one of the most effective methods of corrosion protection. Inhibitors are substances that minimize corrosion in aggressive environments, with only a low concentration required. The inhibitors are chemically adsorbed on the surface of the metal and a protective thin film is formed . The mechanism of the inhibitors could be described as anodic, cathodic, or a mix of the two. Anodic inhibitors, also known as passivation inhibitors, alter an anode reaction. Corrosion potential of the metal is shifted to …

Ductile Corrosion-Free Self-Centering Concrete Elements, Maged Youssef, Mohamed E. Meshaly, Ahmed Elansary

Civil and Environmental Engineering Publications

Corrosion is a major factor in the deterioration of reinforced concrete (RC) structures. To mitigate this problem, steel bars can be replaced with glass-fiber-reinforced-polymer (GFRP) bars. However, the lack of ductility of GFRP-RC elements has prevented their use in many structural applications, especially in seismic areas. Superelastic shape memory alloy (SMA) bars have been proposed to be used in seismic areas because of their self-centering characteristics. Also, they have the added advantage of being corrosion resistant. This paper examines the combined use of SMA and GFRP bars to achieve ductile self-centering and corrosion-free elements. The first challenge for such a …

Flexural Behaviour Of Superelastic Shape Memory Alloy Reinforced Concrete Beams During Loading And Unloading Stages, Yamen Ibrahim Elbahy, Maged Youssef

Civil and Environmental Engineering Publications

Trend of using smart structures, which can adjust when exposed to severe unexpected loading, is increasing. One of the methods to achieve such structures relies on smart materials. For example, replacing conventional steel reinforcing bars in Reinforced Concrete (RC) structures with superelastic Shape Memory Alloy (SMA) bars significantly reduces the residual deformations caused by post-yielding behaviour. This paper provides in-depth understanding of the flexural behaviour of SMA RC beams. A sectional analysis method, which predicts the flexural behaviour of SMA RC beams during both loading and unloading stages, is adopted and validated using available experimental data. An extensive parametric study …

Benefits Of Aluminum: Comparing The Common Materials In The Bar Grating Industry, Joanthan Geiser

Williams Honors College, Honors Research Projects

The main aim of this project is to study the wholistic behavior of the 6xxx series of aluminum for use in the bar grating industry for a waste water treatment environment. This project will study the comparison of certain aluminum 6xxx series alloys to steel, stainless steel, and glass fiber-reinforced plastic. While comparing these materials, it will look at the mechanical properties such as modulus of elasticity, yield strength, and ultimate tensile strength. In addition, the available corrosion test of the 6xxx series aluminum alloys will be examined to find a generalization of the corrosion behavior for this series. A …

Cataloging The Degree Of Sensitization Via Electrochemical Reactivation For Studying The Corrosion Behavior Of Inconel 718, Austenitic, And Duplex Stainless Steels, Bradley Lynes

Williams Honors College, Honors Research Projects

Corrosion resistant materials can be expensive, but usually reduce the life cycle cost of metallic assets. However, negligent sensitization of these materials can lead to aggressive, intergranular corrosion. Using the methodology of the double loop electrochemical potentiokinetic reactivation (DL-EPR), this project investigates different steel reinforced bars and Inconel to determine the degree of sensitization after a heat treatment of 900°C for 2 hours. The purpose of this research is to validate and determine the appropriate test parameters for performing further DL-EPR test in the future. Additionally, the kinetics observed for each sample during the DL-EPR test will be analyzed and …

Stress Corrosion Cracking Of Stainless-Steel Reinforced Concrete, Nathan Frye

Williams Honors College, Honors Research Projects

Stainless steel rebar is one of the most corrosion resistant reinforcing methods for concrete structures. Stainless steel is used for its chromium content and its ability to form a passive oxide corrosion resistant layer. The presence of chloride is one of the largest attackers of this passive film and able to penetrate concrete due to its porous characteristics. This study evaluates the mechanical performance of different stainless steels relative to their changing environments. It is expected that as chloride concentration values increase, mechanical properties will decrease. This will be tested by performing tensile tests on stainless steel rebar sample that …

Development Of Cardanol-Based Epoxy Coating, Nicholas Pottschmidt

Williams Honors College, Honors Research Projects

The purpose of this project was to determine the suitability of cardanol glycidyl ether (CGE) as a substitute for trimethylolpropane triglycidyl ether (TMPGE) as the reactive diluent in epoxy coatings. CGE may be a naturally-derived alternative to TMPGE, which is a commonly-used petroleum-derived reactive diluent. Epoxy coatings were formulated with CGE replacing increasing amounts of TMPGE in the formulation. Corrosion protection provided by the coatings was evaluated with electrochemical impedance spectroscopy (EIS). Mechanical properties of the coatings (hardness, flexibility, adhesion, and impact resistance) were evaluated with applicable ASTM standards.

EIS results revealed the coating formulated with only CGE had superior …

Particle Size-Dependent Microstructure, Hardness And Electrochemical Corrosion Behavior Of Atmospheric Plasma Sprayed Nicrbsi Coatings, Peng Sang, Liang-Yu Chen, Cuihua Zhao, Ze-Xin Wang, Haiyang Wang, Sheng Lu, Dongpo Song, Jia-Huan Xu, Lai-Chang Zhang

Research outputs 2014 to 2021

Particle size is a critical consideration for many powder coating-related industries since it significantly influences the properties of the produced materials. However, the effect of particle size on the characteristics of plasma sprayed NiCrBSi coatings is not well understood. This work investigates the microstructures, hardness and electrochemical corrosion behavior of plasma sprayed NiCrBSi coatings synthesized using different-sized powders. All coatings mainly consist of Ni, N3B, CrB, Cr7C3 and Cr3C2 phases. The coatings produced by small particles (50–75 μm) exhibit lower porosity (2.0 ± 0.8%). Such coatings show a higher fraction (15.5 vol.%) of the amorphous phase and lower hardness (700 …

Calculation Of Oxygen Diffusion Coefficients In Oxide Films Formed On Low-Temperature Annealed Zr Alloys And Their Related Corrosion Behavior, Lina Zhang, Liang-Yu Chen, Cuihua Zhao, Yujing Liu, Lai-Chang Zhang

Research outputs 2014 to 2021

The growth of oxide film, which results from the inward oxygen diffusion from a corrosive environment, is a critical consideration for the corrosion resistance of zirconium alloys. This work calculates the oxygen diffusion coefficients in the oxide films formed on zirconium alloys annealed at 400~500 °C and investigates the related corrosion behavior. The annealed samples have a close size for the second-phase particles but a distinctive hardness, indicating the difference in substrate conditions. The weight gain of all samples highly follows parabolic laws. The weight gain of the sample annealed at 400 °C has the fastest increase rate at the …

Microwave Detection Of Surface Breaking Cracks In Metallic Structures Under Heavy Corrosion And Paint, John Robert Gallion

Masters Theses

"We live in the world of "aging infrastructures". In this environment, critical and heavily utilized infrastructure, i.e. ships, planes, bridges, etc., are operating at or beyond their designed age. Replacement is no longer an option and "retirement for cause" is the current approach to maintenance and replacement. Consequently, there is an ever-increasing demand for efficient and robust nondestructive evaluation (NDE) methods that can determine the physical health of these structures. Large structures, which are primarily made of metals, either steel or aluminum, are susceptible to high-stress cracking and corrosion. Stress-induced cracks in heavily corroded steel, used in bridges, railroads, storage …

The Effect Of Flinak Molten Salt Corrosion On The Hardness Of Hastelloy N, David Kok

Honors Program Projects

The desire to reduce pollution caused by electricity production has led to a call for the replacement of conventional fossil fuel power plants. In order to fulfill this goal, a large amount of new nuclear reactors is required, and this provides the opportunity to put new and innovative reactor designs into production. The Molten Salt Reactor (MSR) is one of the most promising concepts, but a suitable combination of molten salt and container material needs to be found to reduce the potential for corrosion before the concept can be put into production. FLiNaK molten salt and the nickel-based alloy Hastelloy …