Civil and Environmental Engineering Commons^™

Corrosion Measurement Of Reinforcing Steel In Concrete Using Electrochemical Impedance Spectroscopy, Eric Sumsion, Dr. Spencer Guthrie

Journal of Undergraduate Research

Corrosion affects reinforced concrete structures throughout the world. Corrosion, induced by concrete carbonation and penetration of chloride ions from deicing salts and/or seawater, reduces the load-bearing area of reinforcing steel, weakens the bond between steel and concrete, and cracks the concrete surrounding the steel. As a result of these effects, corrosion can cause premature failure of reinforced concrete structures.

Reliability-Based Design Optimization Of Concrete Flexural Members Reinforced With Ductile Frp Bars, Bashar Behnam, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

In recent years, ductile hybrid FRP (DHFRP) bars have been developed for use as tensile reinforcement. However, initial material costs regain high, and it is difficult to simultaneously meet strength, stiffness, ductility, and reliability demands. In this study, a reliability-based design optimization (RBDO) is conducted to determine minimum cost DHFRP bar configurations while enforcing essential constraints. Applications for bridge decks and building beams are considered, with 2, 3, and 4-material bars. It was found that optimal bar configuration has little variation for the different applications, and that overall optimized bar cost decreased as the number of bar materials increased.

Performance Of Reinforced Concrete Beams Strengthened With Mechanically-Fastened Composite System Under Corrosive Environment, Amna Zaid Suwaid Al Nassibi

Theses

This study examines the effects of corrosion exposure on the flexural response of reinforced concrete (RC) beams strengthened with a powder-actuated fastened (PAF) composite system. Twenty-one RC beams were constructed and tested to failure under four-point bending. The corroded beams were subjected to 30, 60, and 100 days of accelerated corrosion that corresponded to measure tensile steel mass losses of 6, 11 and 18% respectively. Other test parameters included width of fiber reinforced polymer (FRP) composite strip, fastener length, and number of fasteners rows.

For the non-corroded beams, the PAF-FRP system resulted in up to 24% increase in beam flexural …

Precast/Prestressed Concrete Truss-Girder For Roof Applications, Peter S. Samir

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Steel trusses are the most popular system for supporting long span roofs in commercial buildings, such as warehouses and aircraft hangars. There are several advantages of steel trusses, such as lightweight, ease of handling and erection, and geometric flexibility. However, they have some drawbacks, such as high material and maintenance cost, and low fire resistance. In this paper, a precast concrete truss is proposed as an alternative to steel trusses for spans up to 160 ft. without intermediate supports. The proposed design is easy to produce and has lower construction and maintenance costs than steel trusses. The proposed design is …

Bringing To Life The World’S Tallest Structure, Jonathan Weigand

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Intended as the centerpiece of constructional developments in Dubai, the Burj Khalifa now stands as the tallest building ever constructed. The uniquely designed foundation consists of a concrete raft supported by a cast-in-place pile system protected by waterproofing membrane to inhibit corrosion. The structural design integrates high-performance reinforced concrete and steel and incorporates an engineered “Y” shape that limits the lateral wind pressure on the building. Engineers applied the latest advancements in high-rise technology to develop an optimized construction plan that consisted of segmented tasks that promoted the staff to work at a quick yet manageable pace. This article details …

Experimental And Numerical Investigations On Bond Durability Of Cfrp Strengthened Concrete Members Subjected To Environmental Exposure, Haider Al-Jelawy

Electronic Theses and Dissertations

Fiber reinforced polymer (FRP) composites have become an attractive alternative to conventional methods for external-strengthening of civil infrastructure, particularly as applied to flexural strengthening of reinforced concrete (RC) members. However, durability of the bond between FRP composite and concrete has shown degradation under some aggressive environments. Although numerous studies have been conducted on concrete members strengthened with FRP composites, most of those studies have focused on the degradation of FRP material itself, relatively few on bond behavior under repeated mechanical and environmental loading. This thesis investigates bond durability under accelerated environmental conditioning of two FRP systems commonly employed in civil …

Performance-Based Seismic Design Of Unbonded Precast Post-Tensioned Concrete Filled Gfrp Tube Piers, Haitham M. Dawood, Mohamed Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a seismic design procedure for self-centering precast post-tensioned bridge piers. The piers presented in this manuscript consisted of concrete filled fiber reinforced polymer (FRP) tubes. A large set of 84 piers with different design parameters were analyzed using finite element models. The backbone curve of each pier was developed and bilinearized. The idealized backbone curves were used to develop a set of empirical equations that were able to reproduce the bilinearized backbone curve of a given pier. Different performance criteria have been proposed for the system according to the intensity and the frequency of occurrence of a …

Photocatalytic Degradation Of Nox By Concrete Pavement Containing Tio₂, Joel K. Sikkema

Faculty Work Comprehensive List

Emissions from motor vehicles cause the concentrations of nitrogen oxides (NOX) in the immediate vicinity of highways to be 30-100% higher than background concentrations. Photocatalytic pavements have been proposed to address this localized pollution problem. Bench-scale evaluation of environmental variables confirmed that nitric oxide (NO) oxidation rate positively correlated with influent NO concentration and irradiance and negatively correlated with relative humidity. However, comparison of the slope of these correlations found significant differences between this study and other published work. Slab water loss, a variable not investigated in prior work, positively correlated with NO oxidation rate at water losses of 0-2% …

An Investigation Of Waste Glass-Based Geopolymers Supplemented With Alumina, Mary U. Christiansen

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

An increased consideration of sustainability throughout society has resulted in a surge of research investigating sustainable alternatives to existing construction materials. A new binder system, called a geopolymer, is being investigated to supplement ordinary portland cement (OPC) concrete, which has come under scrutiny because of the CO2 emissions inherent in its production.

Geopolymers are produced from the alkali activation of a powdered aluminosilicate source by an alkaline solution, which results in a dense three-dimensional matrix of tetrahedrally linked aluminosilicates. Geopolymers have shown great potential as a building construction material, offering similar mechanical and durability properties to OPC. Additionally, geopolymers have …

Evaluation Of Bridge Maintenance Interventions Under Changing Deterioration Rates: A Markovian-Based Methodology, Dilum Fernando, Baolin Wan, Scott Walbridge

Civil and Environmental Engineering Faculty Research and Publications

Markovian transition probability matrices employing condition states are often used in bridge management systems to determine optimal intervention strategies. This approach assumes a constant deterioration matrix throughout the entire analysis period. However, in order to adequately model and evaluate intervention options such as fiber-reinforced polymer (FRP) strengthening, it is necessary to model the impact of the intervention on the deterioration rate. This paper presents a Markovian based approach to model interventions that impact deteriorating rates. A model employing this approach is proposed. A methodology to determine the optimal intervention strategy based on steady state probabilities is then presented. The proposed …

Assessing Corrosion Damage In Post -Tensioned Concrete Structures Using Acoustic Emission & A Preliminary Investigation Of Biopolymer Doped Cement Mortar For Use In Structural Restoration, Aditya Appalla

Theses and Dissertations

A sizeable portion of the civil infrastructure is made from concrete. An estimate shows that about 7 billion cubic meters of concrete is made annually worldwide. With the deterioration of the infrastructure due to aging or external factors, significant monetary and technological investment is needed for condition evaluation, maintenance and repair. Two areas that account for a considerable portion of this investment are condition evaluation for maintenance of corroded concrete structures and mortar patching for repair and rehabilitation.

The primary method of evaluation of a structure is by visual inspection. But this method is limited as some crucial areas in …

Kelvin Probe Electrode For Contactless Potential Measurement On Concrete-Properties And Applications, Michael Thomas Walsh

USF Tampa Graduate Theses and Dissertations

The practical feasibility of using a Kelvin Probe as a novel reference electrode in the measurement of both potential and polarization pulse response of reinforcing steel in concrete is demonstrated. Potential values measured using a KP reflect greater stability and repeatability than can typically be attained with conventional reference electrodes. Duplicate reinforced concrete beam test specimens with well-differentiated centrally corroding rebar segments were analyzed using both the Kelvin Probe (KP) and a conventional Saturated Calomel Electrode (SCE). Potential profile maps were developed using potential values recorded under static conditions with both the SCE and the KP. Nominal polarization resistance was …

Conductive Concrete For Electromagnetic Shielding – Methods For Development And Evaluation, Aaron P. Krause

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

This research investigates the development and evaluation innovative methods for the use of conductive concrete as an electromagnetic shield. New testing methods are developed to determine the best conductive components to use in the design of a concrete mixture for shielding that shows the best promise. The conductive concrete mixture has the potential to provide electromagnetic shielding that is cost-effective in terms of construction, operation, and maintenance compared to conventional approaches. Two testing methods, Small Sample Testing and Large Slab Testing, are developed based on standardized testing methods that have been modified for the testing of conductive concrete mixtures. As …

Durability Of Reinforced Concrete Incorporating Crushed Waste Brick As Coarse Aggregate, Matthew Adamson

All Theses

Using crushed bricks as aggregates in concrete is of particular interest to preserve natural aggregate sources as well as to reduce waste, as it has been estimated that 10% to 30% of all waste in landfills in the united States comes from construction and demolition wastes. By recycling some of these wastes, the sustainability of a project can be improved. However, it is important concrete incorporating these wastes is as durable or more durable then conventional concrete, or will it have a shorter service life. Durability of concrete is its ability to resist deterioration from its external environment such as …

Pullout Strength Of Epoxy Anchors Installed Underwater, Jeffrey Lee Blanchette

Master's Theses

This work presents the development of a test program and the results from the final round of testing to better understand the effect a submerged anchor installation has on the pullout strength of epoxy anchors. Two different epoxies were tested at embedment depths of two, four, and six bar diameters. These tests utilized three distinct installation procedures under dry and submerged conditions. The testing program occurred over five phases, with the final round used in analysis consisting of 24 anchor pullout tests. These tests showed that the presence of water did not have an effect on the epoxy bond when …

Incorporation Of Life Cycle Models In Determining Optimal Wind Energy Infrastructural Provision, Brendan Cleary, Aidan Duffy, Alan O'Connor

Conference papers

The deployment of wind energy has grown rapidly over the last two decades with an average annual growth rate of more than 26% since 1990. During this period the development and innovation of wind turbines has resulted in continual growth in wind turbine size with output ranges of 10-15MW likely to be deployed by 2020. This increased output has a knock-on effect on the growth of rotor diameters and tower heights. Wind turbine towers are required to become taller, stronger and stiffer in order to carry the increased weight and associated structural loading. Consequently, the dimensions of the tower cross-sections …

Behavior Of Segmental Precast Posttensioned Bridge Piers Under Lateral Loads, Haitham Dawood, Mohamed Elgawady, Joshua Hewes

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Abstract a segmental precast posttensioned (SPPT) bridge pier is an economic recentering structural system. Understanding the seismic behavior of a SPPT system is an important step toward its application in high seismic zones. This paper presents a detailed three-dimensional finite-element (FE) model that was developed using the ABAQUS platform. a brief description and discussion of cyclic tests on eight large-scale SPPT piers is also presented. Four of the piers were constructed and tested to a predefined degree of damage. Then, these piers were retrofitted and retested. the FE models developed and presented in this paper predicted the backbone curves of …

High-Volume Fly Ash Concrete For Sustainable Construction, Jeffery S. Volz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

With worldwide production of fly ash approaching 800 million tons annually, increasing the amount of fly ash used in concrete will remove more material from the solid waste stream and reduce the amount ending up in landfills. However, most specifications limit the amount of cement replacement with fly ash to less than 25 or 30%. Concrete with fly ash replacement levels of at least 50% - referred to as high-volume fly ash (HVFA) concrete - offers a potential green solution. the following study investigated the structural performance of HVFA concrete compared to conventional Portland-cement concrete. Specifically, the research examined both …

Effects Of Alternate Cementitious Materials On Compressive Strength And Environmental Impacts Of Cement Mix Designs., Mitchell R. Bush

Materials Engineering

Specific proportions of Portland cement, fly ash, and blast furnace slag cement mixtures where chosen by a ternary phase diagram to be investigated. By experimental testing and company data history fly ash was limited to not exceed 30% and contribution of Portland cement must be over 50%. Ten chosen mix designs were batched by following ASTM C305-94 and cured for twenty-eight and forty-two days, the extended cure length allows the reaction of pozzolanic material with calcium hydroxide to complete. Compressive strength testing at forty-two days yielded low strength for mix designs with 20% or less Portland cement compared to our …

Implementation, Design, And Cost Analysis Of A Concrete Washout System, Omar Adina

BioResource and Agricultural Engineering

With the increase of environmental pollution in today’s world, many strategies and regulations are being enforced. These enforcements come from the state and federal governments, but public awareness is often overlooked. Stormwater regulations here in California have dramatically changed over the last decade, as the topic is investigated more often.

This senior project encompassed the design prototype and cost analysis of a permanent concrete washout station for the BioResource and Agricultural Engineering Department at California Polytechnic State University, San Luis Obispo. The design parameters given were to construct a steel bin for the excess concrete to be dumped into during …

Concrete Design For Traffic Application, Marc Shields

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Inductive charging of electronic devices is a newer technology that is capable of transferring electrical power without physical contact through wiring. Research is currently being done to find and improve ways to implement this technology on electric cars. If this type of technology pas implemented on a large scale throughout much of the country, electrical or hybrid cars could travel across counties and states without depleting their batteries.

The current problem with electric cars is that they have a limited range of travel. Even with larger batteries with much more capacitance, the range of pure electric cars usually does not …

Structural Performance Of Reinforced Concrete Flat Plat Buildings Subjected To Fire, Sara Jean George

UNLV Theses, Dissertations, Professional Papers, and Capstones

Reinforced concrete structures are typically considered to have inherent resistance to fire. However, several concrete structures around the world have experienced partial or total collapse under fire. Reinforced concrete flat-plate is a type of structural system widely used for office and residential buildings. Flat plate construction is prone to punching shear failure at slab-column connections which may lead to a catastrophic progressive collapse. The slabs of flat-plates generally have very thin concrete cover leaving steel reinforcement more sensitive to thermal loads. Little is known in the engineering community about the structural performance of flat-plate structures subjected to fire. Through a …

Investigating The Use Of Pozzolans In Portland Cement Concrete And Inorganic Polymer Mortar, Omar Abdelmalek Saleh

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of pozzolans offers promising signs for a change in the cement industry. Pozzolan in its natural and artificial forms can be used to improve cement properties or to synthesize new cement. This study investigates the use of pozzolans in portland cement concrete and inorganic polymer mortar (geopolymer mortar).

This thesis is divided into two phases. Phase 1 investigates the use of natural pozzolan as a partial replacement of portland cement in concrete. In this phase two types of class N pozzolan are used separately to develop concrete mixtures contain different percentages of class N pozzolan. Fresh concrete properties …

Recycling Concrete For Sustainable Construction, Joseph M. Dardis

ETD Archive

The demolition of concrete structures has made concrete debris the largest portion of the waste stream in the U.S. With landfills becoming scarcer, the need to recycle demolition debris is becoming increasingly relevant. An effective way to recycle this material is to produce recycled concrete aggregate (RCA) and use this material in the reconstruction of buildings and roads. Producing and re-using RCA will reduce landfill waste and save energy by minimizing the production and transport of natural aggregates. The focus of this thesis is to quantify how much energy can be saved by producing and re-using RCA instead of landfilling …

Feasibility Of Expanding The Use Of Steel Slag As A Concrete Pavement Aggregate, Brad A. Fronek

ETD Archive

Sustainability has become an important aspect of developed countries throughout the world. Sustainability is the ability to use byproducts and or waste materials from industry and recycle these materials in such a way that the application of the materials provides a beneficial use in the manufacturing or construction sector. As the United States and the rest of the world continue to grow, so too does the demand on the limited natural resources throughout the world. It is this demand on the resources that has brought the idea of sustainability to the forefront of research and design.The transportation industry continues to …

Analysis Of Uncontrolled Concrete Bridge Parapet Cracking, Jeffrey D. Bazzo

ETD Archive

The Ohio Transportation has recently identified the problem of wide-spread premature cracking of concrete bridge parapets throughout its District 12 region (Northeast Ohio). Many of the bridge decks that contain these prematurely cracked parapets are of relatively recent construction. In severe cases, replacement of the parapet may be required before replacement of the bridge deck itself. This incurs a sunk cost upon the bridge owner, as the parapets will again be replaced during the regularly scheduled replacement of the bridge deck. In a recent instance, the replacement of a cracked parapet (without replacing the deck) cost District 12 approximately $140,000. …

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 …

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 …

Strengthening Of Reinforced Concrete Beams Pre-Damaged In Shear, Yousef Mohammed Bachar Chekfeh

Theses

Repair and strengthening of existing reinforced concrete (RC) structures has increased drastically in recent years. Shear reinforcement in RC beams is typically of a small bar diameter, and hence any shear-damage would result in a severe safety hazard and a catastrophic mode of failure especially under extreme loading events. The present work was initiated to the effectiveness of different composite strengthening systems; namely externally bonded carbon fiber reinforced polymer (EB-CFRP), and near surface mounted glass fiber reinforced polymer (NSM-GFRP) to prolong the functional service life of RC beams pre-damaged in shear. It comprised experimental testing and analytical investigation.

The experimental …

Development Of A Structured Concrete Thermocline Thermal Energy Storage System, Bradley M. Brown

Graduate Theses and Dissertations

The past couple of decades have shown a concern when considering the way the world obtains its power. The focus has been switching from fossil fuels that have been used for hundreds of years to renewable energy sources, such as the sun. Solar energy is readily and infinitely available for harnessing. One problem with solar energy, though, is its inability to be used during the night time and during cloud covered weather. A solution to this problem is the use of energy storage mechanisms. For solar plants that use solar thermal energy (concentrating solar power plants), thermal energy storage (TES) …