Engineering Commons^™

On The Development Of 8,000 Psi Geopolymer Mortar For Practical Use In Field Applications, Remington Gabriel Reed

Graduate Theses and Dissertations

Although there are several perceived benefits from the use of geopolymer binder as an alternative to ordinary portland cement in concrete materials, it is not widely used in field applications. Geopolymer materials have no set guidelines for mixture design and often require heat curing to facilitate strength gain. Additionally, many geopolymers are created using carefully controlled and high quality materials and activator chemicals. These factors greatly affect the practicality of the material. The goal of this research was to create a geopolymer material capable of achieving high compressive strengths at 28 days without heat curing, and using only readily available …

Effect Of Cement Content On Concrete Performance, Caleb Joshua Lebow

Graduate Theses and Dissertations

Of all the traditional concrete materials, portland cement has the greatest impact on mixture cost and the environment. Cement is in many ways the glue holding concrete together (Weiss, 1999), and as such, it plays a major role in fresh and hardened concrete properties. Without the proper range of cement in the mixture, low strength development or excessive shrinkage may occur leading to premature deterioration. The Arkansas Department of Transportation (ARDOT) recognizes two types of concrete for use in bridge construction, Class S and Class S(AE). This paper focuses on the findings from testing of Class S(AE) concrete, short for …

Epoxy Interlocking: A Novel Approach To Enhance Frp-To-Concrete Bond Behavior, Cheng Jiang, Baolin Wan, Yu-Fei Wu, John Omboko

Civil and Environmental Engineering Faculty Research and Publications

This paper presents a novel approach which can enhance the interfacial bond behavior between fiber reinforced polymer (FRP) composite material and concrete. Epoxy ribs are formed by grooving on the concrete surface before epoxy is applied. The dowel action from the epoxy ribs leads to an “epoxy interlocking” effect. The mechanism of the proposed epoxy interlocking approach was analyzed in this paper from both adhesion and interlocking aspects. Furthermore, the partial interaction of the epoxy interlocking was quantified and calibrated by experimental results. The epoxy interlocking in the tested specimens led to an 88.8% increase in bond strength on average. …

Detection Of Multiple Flaws In Concrete Bridge Decks Using Ultrasonic Wave Propagation, Ece Erdogmus, Eric Garcia, Michael Schuller, Donald Harvey, Kelsey Stithem, Monica Houck

Nebraska Department of Transportation: Research Reports

No abstract provided.

Building A Handicap Accessible Entrance And Gabion Wall, David C. Marter

Construction Management

As people age, their bodies naturally deteriorate and often times people are confined to wheelchairs in order to get around. Uneven and unstable ground is a large obstacle for people who live confined to a wheelchair. This project was derived and designed in order to help a family with multiple family members bound to wheelchairs to allow them an easier point of access into the home. The project itself consists of the construction of a concrete walkway and a gabion wall to provide some additional aesthetics. The concrete pathway ranges from the driveway to a paver pathway that curves around …

Self-Healing Microcapsules As Concrete Aggregates For Corrosion Inhibition In Reinforced Concrete, Homero Castaneda, Marwa Hassan, Miladin Radovic, Jose Milla

Publications

Reinforced Concrete (RC) structures are vital to the US’s civil infrastructure for their strength and versatility. Unfortunately, RC elements deteriorate rapidly when exposed to corrosive environments. One possible solution is to extend the life of RC elements and systems using microencapsulated corrosion inhibitors to reduce the rebar corrosion rate. The capsules house an anodic corrosion inhibitor agent including calcium nitrate (CN) and triethanolamine (TEA). The integration of such microencapsulated materials will enhance the durability and extend the useful life by controlling the corrosion precursors and the corrosion process during damage evolution. Therefore, this work aims to develop and characterize the …

Fungi: A Neglected Candidate For The Application Of Self-Healing Concrete, Congrui Jin, Rui Yu, Zhonghe Shui

Department of Civil and Environmental Engineering: Faculty Publications

Self-healing mechanism in concrete has been so far achieved mainly by three approaches: autogenous healing, encapsulation of polymeric material, and biologically induced mineralization of calcium carbonate. The microbial approach prevails over the other two approaches due to the high compatibility between the filler material and the concrete compositions. Although the term “microbe” refers to many different types of organisms, research work on self-healing concrete has been so far restricted to bacteria. In this perspective article, we review the current status of bacteria-mediated self-healing concrete and summarize the prospects for future advances. In particular, we point out that fungi may have …

Evaluation Of The Performance And Cost-Effectiveness Of Engineered Cementitious Composites (Ecc) Produced From Region 6 Local Materials, Gabriel Andres Arce Amador, Tyson Rupnow, Marwa Hassan

Publications

The project objective is to develop cost-effective Engineered Cementitious Composites (ECC) with locally available ingredients in Region 6 to address the deficiencies observed in ordinary concrete materials. The study explored the utilization of two types of river sands (coarse and fine), two types of PVA fibers (long and short), four levels of cement replacement with Class F fly ash, and the implementation of recycled crumb rubber in the performance of ECC materials. A total of 24 mix designs were prepared and evaluated in compression, tension, and bending to assess its mechanical properties. Furthermore, the cracking characteristics of the materials produced …

Bridge Deck Overlays Using Ultra-High Performance Concrete, Craig Newtson, Brad Weldon

Publications

This study investigated the use of a locally produced ultra-high performance concrete (UHPC) as an alternative to typical overlay materials. Several bond strength tests including slant-shear, splitting tension, and direct tension tests were performed to assess the bond strength between UHPC and normal strength concrete (NSC) substrate with varying surface textures. Tests were also conducted to assess the early-age and longer-term shrinkage behavior and coefficient of thermal expansion of the UHPC as well as rapid chloride permeability testing. Good bond between UHPC and NSC substrate was observed even with inadequate surface texture. Combined shrinkage and thermal effects were investigated for …

Coir Fiber Reinforced Concrete, Jose De La Serna, Moses Karakouzian

AANAPISI Poster Presentations

This poster exhibits the testing and research done on general Portland Cement Concrete with the addition of coir (coconut) fibers as reinforcement. Using the fundamental constituents of cement (water, cement, fine and coarse aggregate) and processed coir fiber, concrete specimens were batched to test for compressive and flexural strengths (per appropriate ASTM standards). Cylindrical and rectangular beam specimens were subjected to loadings until failure occurred. The capacity and modes of failures of the specimens were observed. It was determined that:

• The addition of processed coir fibers decreases the overall strength of general Portland Cement Concrete. • The tested concrete’s …

Waterproofing Options For Bridge Decks, Danny Wells, Sudhir Palle, Theodore Hopwood Ii

Kentucky Transportation Center Research Report

Due to the increasing use of deicing chemicals and the subsequent intrusion of chlorides into bridge decks, it is necessary to expand the use of available protective measures, including waterproofing materials. Waterproofing options that fall into three categories; 1) membranes (liquid and sheet systems), 2) friction polymers (laminates), and 3) polymer asphalts. This study assessed the waterproofing characteristics of these products. Prior to this study, no common test had been established to compare the performance of waterproofing products. A test method was developed that closely follows ASTM D5084, “Standard Test Methods for Measurement of Hydraulic Conductivity of Saturated Porous Materials …

Modeling And Simulation Of Damage In The Brazilian Indirect Tension Test Using The Finite-Discrete Element Method, Jeremiah C. Leyba

Civil Engineering ETDs

The Brazilian indirect tension test is used to investigate possible correlations between progressive damage and associated permeability changes. The test offers ease of replicability with a damage behavior known to lead to fracture openings as a tool for interpreting the indirect tensile strength of concrete and rocks. This behavior can lend insight into the nature of tensile damage and fracture progression in association with changes in permeability. The nature of these brittle materials is known to exhibit rapid failures in the Brazilian indirect tension test and require a method to retard the progression of damage for the possibility of acquiring …

Feasibility Of Hybrid Thermoplastic Composite-Concrete Load Bearing System, Camerin M. Seigars

Electronic Theses and Dissertations

Thermoplastic composites have many advantages over thermoset composites such as being recyclable, rapidly manufacturable, and more impact resistant. The goal of this thesis is to assess the feasibility of using thermoplastic composites in structural applications through literature review, mechanical testing, design of a load-bearing hybrid composite-concrete structures, and the implementation of thermoplastic composites for tensile reinforcement of concrete. The study had four objectives covering the stated goal.

1. Conduct a literature review to direct thermoplastic material selection
2. Characterize thermoplastic material mechanical properties using standardized mechanical testing
3. Design a hybrid composite-reinforced concrete beam, and
4. Develop thermoplastic shear connectors to develop composite action …

Comparison Of Deep Convolutional Neural Networks And Edge Detectors For Image-Based Crack Detection In Concrete, Sattar Dorafshan, Robert J. Thomas, Marc Maguire

Civil and Environmental Engineering Faculty Publications

This paper compares the performance of common edge detectors and deep convolutional neural networks (DCNN) for image-based crack detection in concrete structures. A dataset of 19 high definition images (3420 sub-images, 319 with cracks and 3101 without) of concrete is analyzed using six common edge detection schemes (Roberts, Prewitt, Sobel, Laplacian of Gaussian, Butterworth, and Gaussian) and using the AlexNet DCNN architecture in fully trained, transfer learning, and classifier modes. The relative performance of each crack detection method is compared here for the first time on a single dataset. Edge detection methods accurately detected 53–79% of cracked pixels, but they …

Understanding Asphalt Concrete Aging Using Nanoindentation, Hasan M. Faisal

Civil Engineering ETDs

Asphalt concrete (AC) is created by mixing liquid asphalt binder with solid aggregates. When asphalt binder is mixed with aggregates, it creates a thin film (about 7-16 microns thick) around the aggregate surface. Fine aggregate (smaller than 0.075 mm size) get entrapped within the binder film or mixed with the binder, and create a phase called mastic. Both asphalt film and mastic play significant roles in aging of asphalt pavement. To this day, tests were performed mainly on the bulk liquid asphalt, but not on the film or mastic. In this study, for the first time, nanoindentation tests were done …

Alternate Reinforcement For Structural Concrete, Barrett Lowe

Construction Management

Concrete has been utilized on construction projects for thousands of years, ranging from the Pyramids to the foundation your home is built on. Innovated upon, concrete and its properties have changed over the years, one of the greatest being the discovery of tensile reinforcement. Rebar, commonly known as reinforcing steel or reinforcement bars, have been used in the construction industry for decades. Ranging in size and application, rebar’s unmatched tensile strength and anti-corrosive properties make it the champion of reinforcing structural concrete. Though the advancement in technology has created a new era where other materials may take its place. Attempting …

Charpy Impact Test Methods For Cementitious Composites: Review And Commentary, Robert J. Thomas, Andrew D. Sorensen

Civil and Environmental Engineering Faculty Publications

Several researchers have recently employed the Charpy method to characterize the high strain rate mechanical strength of cementitious composites. This paper provides a critical review of existing applications of the Charpy method for impact testing of cementitious composites. Studies have employed various specimen sizes and geometries. Additionally, some studies have tested notched specimens while others have tested plain. Furthermore, varying methods of normalization result in results reported in a variety of incompatible units. The lack of consistency between studies limits the basis for comparison and the ability to validate results, which demonstrates a clear need for a standardized method for …

Hot Applied Sealant Bond Test For Joints With Penetrating Sealers, Lieska Halsey

Nebraska Department of Transportation: Research Reports

Recently a concern has been raised for hot applied sealant bond for joints with penetrating sealers. The objective of this study will be to determine if the bond between the sealant and the concrete is compromised by the sealer currently approved to be used in Nebraska. The expected results will be that the bond is not compromised and is serving for the expected joint service life.

Compressive Strength Of Concrete Cylinders By Different Preparation Methods: Sulphur, Neoprene Pads And Grinding, Wally Heyen, Lieska Halsey

Nebraska Department of Transportation: Research Reports

The purpose of this evaluation is to compare the effects of four types of cylinder preparation methods prior to compressive strength testing in accordance to ASTM C 39.

The Production Of Pyrolytic Biochar For Addition In Value-Added Composite Material, Douglas Matthew Cuthbertson

Electronic Thesis and Dissertation Repository

Pyrolytic biochar has recently gained attention for its potential value as a carbon sequestering by-product that can be used in industrial applications. While biochar is typically targeted for soil amendment applications, higher value applications such as addition in consumer products and building materials needs to be investigated.

In this study, biochar is produced from three different Canadian feedstocks using three different pyrolysis methods. The biochar is characterized to determine the effects that feedstock selection and pyrolysis conditions has on biochar properties. The biochar is also incorporated into concrete at varying concentrations to create a lightweight and sustainable material. The effect …

Investigating Early Age Behavior Of Portland Cement Concrete In Arid Regions, Evan Wolf

Open Access Theses & Dissertations

The early-age behavior and properties of portland cement concrete change rapidly over time as a result of the hydration process. Comprised of a series of chemical reactions, this process accelerates nonlinearly with the curing temperature. Gaining knowledge and understanding of the phases of the hydration process (i.e., dormant, setting, and hardening) plays an important role in the timely opening of roads, resuming of construction, and achieving long-term performance. Standard tests such as ASTM C403 arbitrarily define the time of initial and final setting of concrete. Despite decades of studies concerning setting times, actual predictions still span hours, while the quality …

Numerical And Experimental Analysis Of Local Buckling Of Axially Loaded Steel Tubes Confined By Concrete And Frp, Nicholas Colbert

Masters Theses

“The hollow core Fiber-Reinforced-Polymer (FRP) concrete circular-steel (HC-FCS) column consists of an outer circular fiber reinforced polymer (FRP) tube, an inner thin-walled circular steel tube concentrically aligned, and a concrete shell between them. Research has been performed on the performance of the member as a whole, but to date, there has been no investigation into the behavior of the steel tube confined in the column. 17 small-scale columns were tested under axisymmetric axial compressions applied directly to the steel tube under displacement control. The conducted parametric study examined the effects of diameter-to-thickness (D/t) ratio, concrete unconfined compressive strength, FRP thickness, …

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 …

Enhancing Frp-To-Concrete Bond Behavior By Epoxy Ribs, Cheng Jiang, Baolin Wan, John Omboko

Civil and Environmental Engineering Faculty Research and Publications

The bond between external bonding (EB) of fiber reinforced polymer (FRP) composite materials to concrete is the weakest link in the strengthened concrete flexural members. There are three mechanisms to transfer the interfacial shear between FRP and the concrete substrate, i.e., adhesion, interlocking and friction. This paper proposes a new approach by grooving on the concrete surface before applying epoxy to make epoxy ribs to increase interlocking. An experimental program was conducted to verify the effectiveness of the proposed epoxy ribs. Six grooves perpendicular to the fiber direction were cut on the bonding surface of the concrete blocks. The grooves …