Engineering Commons^™

Lcc Mse Walls, Joel Smith

Theses and Dissertations

Lightweight cellular concrete (LCC) is mainly a mixture of water, cement, and foam bubbles. LCC generally has a cast density between 20-60 pcf and an air content between 49-84%. LCC is often used as a fill material because it has a low unit weight which reduces settlement. LCC is increasingly being considered as a backfill behind Mechanically Stabilized Earth (MSE) walls and embankments. Although engineers are using LCC in MSE walls or free face walls (MSE wall without the concrete panels or reinforcements), there is presently a lack of information regarding the performance and behavior of LCC to guide them. …

Persistence And Mitigation Of Pfas Within Concrete Stormwater Drainage Infrastructure, Jason R. Mcdonald

Theses and Dissertations

The persistence, fate, and transport of per- and poly-fluoroalkyl substances, which have been shown to have adverse effects on human health, have been previously studied in environmental media such as soils and groundwater. This study investigates concrete, a medium that is rarely studied but frequently present in instances where PFAS originating from AFFF releases and spills have occurred. Used heavily throughout aviation firefighting, AFFF poses environmental hazards due to the length of PFAS degradation and toxicological implications, thus its classification as a forever chemical. From the very limited reports to date, studies have suggested very slow release from concrete, potentially …

The Development Of A Finite Element Model For Ballistic Impact Predictions, Richard Allen Perkins

Theses and Dissertations

Concrete is a widely used product and is an important application throughout industry due to its inexpensive cost and wide range of applications. This work focuses on understanding the behavior of high strength concrete in high strain rate ballistic impact loading scenarios. A finite element analysis was created with the implementation of the Concrete Damage and Plasticity Model 2 (CDPM2) to represent the material behavior. The model’s parameters were calibrated to existing literature and the results were analyzed by a comparison of the impact velocity to residual velocity and a qualitative assessment of the impact crater. The model captured the …

Assessment Of Key Imperatives For Enhancing Precast Adoptability In Egypt, Mostafa Sameh

Theses and Dissertations

Precast Concrete’s modular application concept is a major construction method that has been used historically seen in various shapes, forms, and with a wide range of constituents. Examples include Ancient Egypt and China among several impressive structures in old civilizations. The major advantages of precast concrete lie in its adaptability, resilience, and versatility which makes precast concrete one of the most agile building materials. Precast concrete as we know it today has been introduced to our markets over the past several decades. Having similar advantages to that of old precast building methods, the road has been paved for wider use …

Use Of Vertical Electrical Impedance For Nondestructive Evaluation Of Concrete Bridge Decks, Enoch Thomas Boekweg

Theses and Dissertations

Nondestructive evaluation of civil infrastructure is increasingly important in the modern world to assess structures, predict longevity, and prescribe rehabilitation or replacement. For concrete bridge decks, one emerging diagnostic technique is vertical electrical impedance (VEI) testing, which is a nondestructive evaluation technology that quantitatively assesses the cover protection offered to steel reinforcement. Because VEI testing is still a relatively new approach to bridge deck inspection, additional studies are needed to increase the interpretability of VEI data. This thesis increases VEI interpretability with two advances. The first advance, presented in Chapter 2, offers an analytical model for interpreting VEI measurements of …

Assessment Of Carbon Dioxide Emission And Its Impact On High-Rise Mixed-Use Buildings In Egypt, Ahmed Salah Hamza

Theses and Dissertations

With Egypt's vision of 2030 focusing on sustainable development with a true emphasis on Carbon Dioxide (CO₂) emission reduction in the newly built cities and high-rise buildings, efforts are exerted on various levels towards accomplishing the vision’s goals. This is achieved through multiple tools and models associated with aiding the reduction of carbon emissions, yet not a clear one was introduced for the mixed-use buildings in Egypt.

Through this work, a significant gap was identified with respect to high-rise buildings carbon emission assessment in Egypt. This was a main driving force for this work in an attempt to …

Investigating The Effects Of Aggregate Size And Reinforcement On Asr Cracking In Concrete Structures Studied With Different Evaluation Methods, David Joseph Bianco

Theses and Dissertations

The objective of this thesis is to investigate different (non-destructive) evaluation methods to assess the effects of reactive aggregate size and reinforcement on ASR affected concrete. It has been shown in previous literature that reactive coarse aggregates lead to more expansion as opposed to reactive fine aggregates. However, there is a lack in the literature exhibiting this relationship using different evaluation methods, such as acoustic emission (AE) and ultrasonic pulse velocity (UPV). Also, the literature does not emphasize the role this relationship plays when the concrete is imposed with stress boundary conditions. Non-destructive test methods, including acoustic emission, are becoming …

Long-Term Performance Of Sustainable Pavements Using Ternary Blended Concrete With Recycled Aggregates, Seth M. Wagner

Theses and Dissertations

The purposes of this study were to (a) design concrete pavement mixtures with recycled concrete aggregates using ternary blends of cementitious materials and a low water-to-binder ratio, (b) measure the fresh and hardened properties of the proposed concrete mixtures and (c) assess the long-term performance of the concrete implementing the use of recycled coarse aggregates. Preliminary investigation into ternary blend combinations via the compressive testing of mortar cubes and isothermal calorimetry was used to predict an optimal blend of cementitious material. Mixes using recycled concrete aggregates at varying replacement rates were tested for fresh and hardened properties using the proposed …

Nondestructive Evaluation Of Corrosion Damage In Reinforced Concrete Aged Slab Specimen, Rawya Abdulsattar Abduljabbar

Theses and Dissertations

The deterioration of concrete bridge decks presents a maintenance challenge for most transportation agencies and bridge owners. This problem increases during the freeze-thaw cycle. De-icing salts can accelerate the deterioration process. Corrosion of steel reinforcement in reinforced concrete structures is considered a dominant factor causing premature deterioration, especially those structures located in a coastal environment. The resulting corrosion product produced has several times the volume of steel, resulting in cracking of the concrete cover if the corrosion is significant. In this study, a bridge deck specimen was subjected to an artificial environment to accelerate the corrosion process. Prior to this …

Assessments Of Concrete Internal Damage Caused By Freeze-Thaw Cycles And Mechanical Loading, Zeqian Li

Theses and Dissertations

Concrete in bridge decks in Northern States, such as Wisconsin, is subjected to both freeze-thaw cycles and mechanical stresses. Standard testing methods are available to evaluate the deterioration of concrete, including ASTM C215 (Dynamic Modulus test), ASTM C1202 (Rapid Chloride Ion Penetrability test), and ASTM WK37880 (ESR test) are available. In addition, ASTM C642 (water absorption test) helps quantification of permeable voids in concrete. These tests have been used to evaluate undamaged concrete or concrete samples after freeze-thaw cycles.

The concrete samples in this study have been subjected to compressive stresses (0.4f_c^') and freeze-thaw cycles (100 to 300 cycles) to …

Delamination Detection In Concrete Using Disposable Impactors For Excitation, Anjali Narendra Patil

Theses and Dissertations

Delaminations in concrete bridge decks result primarily from corrosion of the reinforcing bars (or rebar). This corrosion leads to volumetric expansion of the rebar. When the rebar expands, concrete cracks, and there is a localized separation of the concrete cover from the underlying concrete. Impact-echo testing is an effective technique to map delaminations on concrete bridge decks. However, mapping speed is limited by necessary retrieval of the impactor for traditional tests. To achieve higher scanning speeds, it is advantageous to use both a non-contact measurement (air-coupled impact-echo) and disposable-impactor excitation. Disposable impactors have the potential advantage of achieving greater deck …

Deicer Usage On Concrete And Asphalt Pavements In Utah, Chase David Thomas

Theses and Dissertations

The objectives of this research were to 1) compile winter maintenance data for the Utah Department of Transportation (UDOT) to directly compare concrete and asphalt pavements with regards to deicer usage and 2) determine if there is a statistical difference in deicer usage on concrete and asphalt pavements. To this end, three data sources were consulted for this research: Material Maintenance Quality Assurance (MMQA) database, UDOT road database, and Google Maps. The final compiled data set prepared for analysis in this research contained deicer quantities by deicer type, pavement surface areas by pavement material type, traffic, longitude, latitude, and elevation …

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 …

Smart Carbon Nanotube/Fiber And Pva Fiber-Reinforced Composites For Stress Sensing And Chloride Ion Detection, Joshua A. Hoheneder

Theses and Dissertations

Fiber reinforced composites (FRC) with polyvinyl alcohol (PVA) fibers and carbon nanofibers (CNF) had an excellent flexural strength in excess of 18.5 MPa compared to reference samples of 15.8 MPa. It was found that the developed, depending on applied stress and exposure to chloride solutions, composites exhibit some electrical conductivity, from 4.20x10^-4 (ohm*m)^-1 to. 4.13x10^-4 (ohm*m)^-1. These dependences can be characterized by piezioresistive and chemoresistive coefficients demonstrating that the material possesses self-sensing capabilities. The sensitivity to stain and chloride solutions can be enhanced by incorporating small amounts of carbon nanofibers (CNF) or carbon nanotube (CNT) into composite structure. Conducted research …

Analysis Of Selected Factors Affecting Concrete Cover Measurements On Bridge Decks, Jeffrey Ryan Hoki

Theses and Dissertations

The objective of this research was to quantify the effects of selected parameters on the accuracy of concrete cover measurements on bridge decks. This research involved three full-factorial laboratory experiments each designed to investigate one of three primary variables. These primary variables included distance to a parallel adjacent bar, distance to a reinforcement intersection, and incorrect bar size input for the cover meter. Each experiment also involved four secondary variables known to affect cover readings. These secondary variables included actual cover depth, meter brand, antenna type, and bar size. Statistical analyses were performed to determine the significance of each factor. …

Freeze-Thaw Durability Of Pervious Concrete, Carson B. Demille

Theses and Dissertations

Although the use of pervious concrete is expanding, only a limited number of scholarly papers have been published on the resistance of pervious concrete to deterioration under frost action. Based on this need for additional research on the durability of pervious concrete in cold regions, the objective of this research was to evaluate the resistance of pervious concrete to degradation during freeze-thaw cycling under different soil clogging and water saturation conditions. The laboratory research associated with this project involved three primary measures of pervious concrete performance, including freeze-thaw durability, compressive strength, and permeability. Testing associated with freeze-thaw durability involved two …

Sensitivity Of Half-Cell Potential Measurements To Properties Of Concrete Bridge Decks, Thad Marshall Pinkerton

Theses and Dissertations

Half-cell potential testing has been recommended as a non-destructive method for assessing the corrosion potential of reinforcing steel in concrete bridge decks. The technique is particularly useful because it can be utilized to evaluate the probability of corrosion before damage is evident at the surface of a bridge deck. The specific objective of this research was to quantify the effects of age, chloride concentration, concrete cover thickness, spatial position, temperature, and presence or condition of epoxy coating on half-cell potential measurements of concrete bridge decks typical of those in Utah. The laboratory testing associated with this research followed a full-factorial …

Biomass And Coal Fly Ash In Concrete: Strength, Durability, Microstructure, Quantitative Kinetics Of Pozzolanic Reaction And Alkali Silica Reaction Investigations., Shuangzhen Wang

Theses and Dissertations

Biomass represents an important sustainable energy resource, with biomass-coal cofiring representing among the most effective and cost efficient CO2 reduction strategies. Fly ash generated during coal combustion represents a technically advantageous, inexpensive, and environmentally beneficial admixture in concrete production, partially replacing cement. However, strict interpretation of American Society of Testing and Materials (ASTM) and American Concrete Institute (ACI) standards prohibits use of fly ashes from any source other than coal in concrete production; therefore, fly ash from biomass coal cofiring is excluded from use in concrete. This dissertation discusses biomass impacts on concrete properties through experiments conducted on several combinations …

Rectification Of 2-D To 3-D Finite Element Analysis In Buried Concrete Arches Under Discrete Loading, Adam D. Aagard

Theses and Dissertations

Construction of tunnels and small- to medium-span bridges is a $12 billion per year industry in the United States, with a significant portion going into buried arch structures. Notwithstanding such expenditure, modern arch design and construction, in many cases, is highly conservative. This is because the closed-form solutions used by most designers today do not correctly account for soil-structure interaction. In fact, soil-structure interaction makes a closed form solution impossible. With the advent of high power computers in recent years, some designers have turned to finite element (FE)modeling as the main vehicle of analysis. Such numerical procedures provide an accurate …

In-Situ Testing Of A Carbon/Epoxy Isotruss Reinforced Concrete Foundation Pile, Sarah Richardson

Theses and Dissertations

This thesis focuses on the field performance of IsoTruss®-reinforced concrete beam columns for use in driven piles. Experimental investigation included one instrumented carbon/epoxy IsoTruss®-reinforced concrete pile (IRC pile) and one instrumented steel-reinforced concrete pile (SRC pile) which were driven into a clay profile at a test site. These two piles, each 30 ft (9 m) in length and 14 in (36 cm) in diameter, were quasi-statically loaded laterally until failure. Behavior was predicted using three different methods: 1) a commercial finite difference-based computer program called Lpile; 2) a Winkler foundation model; and, 3) a simple analysis based on fundamental mechanics …