Engineering Commons^™

An Investigation On The Effects Of Cellulose Nanofibrils On The Performance Of Cement Based Composites, Hosain Haddad Kolour

Electronic Theses and Dissertations

Cellulose nanofibrils (CNFs) are hydrophilic biodegradable nanoparticles (typically, less than 0.2 mm in length and 20-50 nm in width) that can be extracted from various plants, trees, and recycled paper stock. Their low density, low toxicity, relatively low cost, high aspect ratio, and high specific surface enable functionalization. In this work, the effects of CNFs on selected properties of cement paste, mortar, and concrete were investigated. For the cement pastes, rheology tests using a simple rheometer showed a reduction in workability as CNF dosage increased. Free shrinkage tests showed an increase in shrinkage at high w/c ratios but a decrease …

Galena Creek Bridge Structural Health Monitoring Instrumentation And Modeling, Leopold Falkensammer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Structural health monitoring (SHM) of an instrumented structure provides numerous benefits when assessing the long-term condition of the structure against degradation, or the short-term condition after an extreme event, such as an earthquake. The Nevada Department of Transportation (NDOT) has an interest in expanding the use of SHM for such assessments. Accordingly, the objective of the current study is to develop and implement a permanent SHM system for the Galena Creek Bridge, the largest concrete cathedral arch bridge in the world, to monitor its response to routine traffic and seismic activity. Completed in 2012, the bridge connects Reno and Carson …

Evaluation Of Concrete Deck Curing Regimens Using Capillary Pressure Sensing System, Samuel Spann

Graduate Theses and Dissertations

Early-age plastic shrinkage cracking is a common problem with the construction of concrete bridge decks due to the high surface area-to-volume ratio and exposure to potentially detrimental environmental effects. Curing regimens are utilized to mitigate cracking risk during the plastic stage of the concrete; the curing regimens evaluated for this study were wet burlap-polyethylene sheeting, two acrylic curing compounds, and one lithium compound. Capillary pressure in the water filled pores has been shown to correlate to the plastic shrinkage cracking risk of concrete. A new portable system has been developed to measure the capillary pressure that could potentially be used …

The Development Of A Novel Experiment On Confined, Flattened Brazilian Disks To Correlate Damage And Permeability In Brittle Geo-Materials, Samuel H. Boyce

Civil Engineering ETDs

This research develops a novel experiment using flattened Brazilian disks under confining pressure with concurrent permeability measurements and acoustic emission monitoring. The purpose of this work is to correlate damage and permeability in brittle geo-materials. Two series of tests are performed on concrete and one series on tuff, under a range of confining stresses between 2.76 and 13.79 MPa. Tests were continued beyond peak stress conditions, capturing data in the post-peak region. The acoustic emission data (cumulative energy and counts) are used to identify damage thresholds and track the progression of microscopic damage. This quantified damage is then correlated to …

Effects Of Coefficient Of Thermal Expansion On Unbonded Concrete Overlay Design And Performance, Gauhar Sabih

Civil Engineering ETDs

With the deterioration of highway pavements across the country, more emphasis is being laid on the rehabilitation of existing pavements. Unbonded concrete overlay (UBCO) is a cost-effective technique used to rehabilitate damaged concrete pavements. The design and performance of UBCO rely on various properties of concrete, of which coefficient of thermal expansion (CTE) is an important one. Concrete CTE has a direct impact on the design and performance of rigid pavements and overlays. CTE regulates the magnitude of curling and related stresses that impact the performance of overlays with regards to cracking, faulting and pavement roughness. Previous research revealed that …

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 …

Steel Test Set-Up For Non-Ductile Concrete Shear Walls, Colin S. Ridgley

Architectural Engineering

The purpose of this project was to provide a robust test set-up for the thesis work being conducted by graduate students, Jerry Luong & Rory de Sevilla. Their research aims to evaluate the feasibility of using fiber-reinforced polymer wraps and splay anchors to retrofit non-ductile concrete shear walls through a series of tests on reinforced concrete walls.

Four key constraints governed the design of the test set-up. First, the wall can be cyclically, laterally loaded to develop data for comparison with theoretical analysis methods. Second, the wall can be axially loaded to simulate interaction effects and prevent a sliding failure …

Habitat For Humanity Global Village: Means & Methods Of Construction In Trinidad & Tobago, Garrett Landress

Construction Management

Habitat for Humanity Global Village is a sector of Habitat for Humanity that focuses on aiding in the construction of homes for those in need around the world. Habitat for Humanity Trinidad and Tobago has been part of Habitat for Humanity Global Village for many years and aids people in need on the Island of Trinidad in the Southern Caribbean. This paper will discuss the construction of a small home for a woman whose family was disowned by her father due to her reluctance to uphold traditional Indian values. Subsequently the family was living in poverty and currently residing in …

Mitigating Carbon Dioxide Emissions In The Cement Industry Through Carbon Capture And Storage, Nicholas J. Cramer

Construction Management

The cement industry is responsible for 7% of industrial energy use, the third largest energy consumer in the world. The industry is also responsible for 7% of global carbon dioxide emissions, the second largest industrial emitter. With current trends continuing, global cement usage will rise with population and urbanization. The low-carbon transition of the cement industry requires innovative technologies and producer cooperation. Carbon capture and storage, known as CCS, is a safe and sustainable solution to significantly reduce the amount being released into the atmosphere. Through CCS, carbon dioxide reacts with natural alkaline minerals, such as fly ash, to create …

Advanced Concrete Course For Cal Poly Construction Management Department, Dante N. Feliciano

Construction Management

This senior project provides a solution to the Construction Management Department at Cal Poly, San Luis Obispo whose curriculum lacks an individual Concrete course. With Concrete being one of the most used building material worldwide, this course will help immensely. The goal of this project is to fill the gap with an Advanced Concrete Course that is prepared and ready to be introduced to future students. The course has an emphasis on outside research learning – where the student gets to become the instructor. Carefully thought out and executed lecture materials are included in the course. Lecture slides give background …

Confronting Retainage And Its Disruptive Effects On The Business Practices Of Commercial Concrete Subcontractors, Arlen Karl Hartoonian

Construction Management

This paper aims to explore the extent of the damage that retainage is capable of inflicting on the financial health of commercial concrete subcontractors and strategies which can be utilized to mitigate or avoid damage to their financial health. The methodology implemented to conduct this exploration is a series of interviews with commercial concrete subcontractors. An analysis of these interviews in conjunction with a thorough literature review demonstrates that retainage does indeed impact financial health of commercial concrete subcontractor though the scale of the operation does make a difference in the severity of this impact. Whether or not the construction …

Comparison Of Carbon Fiber And Fiberglass On Concrete Strength, Justin A. Baker

Construction Management

The purpose of this paper is to compare two common polymers of the construction industry and determine if there are benefits of using them in concrete application to increase overall strength. The goal of the project is to complete a full experiment, utilizing concrete cylinders and beams to test the compressive and tensile properties of fiberglass and carbon fiber. This paper provides data from the experimentation of the compressive and tensile tests of carbon fiber and fiberglass to prove that these polymers are superior and aid in overall concrete strength. The experiment proved that carbon fiber is superior to fiberglass, …

Interim Field Guide For Construction And Testing Of Concrete Shear Wall With Added Frp Layer, Carlos Alberto Espitia

Construction Management

In Los Angeles, many of the hospitals are no longer up to code as they were built in the 1970’s. The shear walls that the hospitals were constructed on stand to experience major failures in the event of a seismic event and this is the issue that this student research team was assigned with. This project was to design, procure, and construct all necessary constraints to be able to test a wall that is fundamentally similar to that of the sheer walls in these hospitals. Once this was complete the goal was to test two walls with an added FRP …

The Influence Of Citric Acid On Setting Time And Temperature Behavior Of Calcium Sulfoaluminate-Belite Cement, Edgar Soriano

Civil Engineering Undergraduate Honors Theses

Today the need to opt for alternative cementitious materials is growing due to environmental reasons and construction time frames that portland cement cannot always satisfy. Calcium Sulfoaluminate (CSA) cements are a strong candidate to supplement or replace portland cement in the construction field for certain applications. In the United States, CSA cement has been limited mostly to pavement repairs because of its rapid initial setting time. The chemical compound responsible for this phenomenon is the alumina. This compound and sulfate are present in larger proportions compared to portland cement. The purpose of this research is to study how the use …

Performance Of Concrete Tunnel Systems Subject To Fault Displacement, Michael Morano

Masters Theses

A Finite Element Analysis (FEA) investigation of concrete tunnel systems traversing seismic faults is carried out to determine how to effectively mitigate the stresses induced in the liner when subject to fault displacement. A parametric study of various fault parameters, both in the damage zone and competent rock, is carried out to determine the site conditions which induce the most stress on the tunnel liner system. Results indicate that friction angle, cohesion, and elastic modulus of fault zones have varying effects on the stresses induced on the liner. The width of damage zone and expected displacements are also investigated and …

Design And Performance Of Fiber-Reinforced Concrete With Adapted Rheology For Construction And Repair Of Bridge Structures, Ahmed Abdelrazik

Doctoral Dissertations

“The objective of this document is to design high-performance fiber-reinforced self-consolidating concrete (FR-SCC) for infrastructure repair and fiber-reinforced super-workable concrete (FR-SWC) for bridge construction. The investigated fibers included propylene synthetic fibers, hooked steel fibers, double and triple hooked steel fibers, hybrid crimped steel fiber and polypropylene multifilament fibers, and micro-macro steel fibers. The fiber volume varied between 0 and 0.75%. An expansive agent (EA) was incorporated to compensate for shrinkage and induce compression in the concrete at early age. Two types of EA (G and K) were employed at 0 to 8%, by mass of binder. The investigated FRSCC and …

Development Of Test Methods For Characterizing Extrudability Of Cement-Based Materials For Use In 3d Printing, Jonathan Thomas Kuchem

Masters Theses

"3D printing is the process of creating three-dimensional objects using an automated additive manufacturing process. The 3D printing process has been used with materials such as metals and polymers, but application with cement based materials for the construction industry has yet to be developed. In this research, two main problems were investigated for printing cement based composite materials: extrudability and tensile reinforcement. Fiber-reinforced concrete (FRC) was studied as an internal reinforcing system to increase tensile/flexural strength. First, FRC was studied to investigate mechanical properties and use of fibers from waste tires as an environmentally friendly option. A reference mixture with …

Analysis Of Standardized Concrete Mixes, Riley Graybeal

Williams Honors College, Honors Research Projects

Concrete is one of the most common materials used in construction. It is mass produced throughout the country, with numerous different designs for concrete mixes. A common practice among concrete manufacturers is to use a standardized concrete mix design. These standardized mix designs are pre-tested and are not usually altered frequently. The hypothesis of this research project is that manufacturers do not constantly investigate new ways to save on their mixes, and simply use the same standardized mix designs.

In this research, investigations into what alterations may reduce the cost of standardized mixes began with a baseline mix design provided …

Incorporation Of Contaminated Sediment Into Environmentally Safe Concrete, Andrew Needs

Williams Honors College, Honors Research Projects

The research performed through this project provided some interesting results on how the different properties of the contaminated sediment can impact the strength of the new concrete.

Average three, seven, and fourteen-day strengths increased when comparing to the baseline mix developed for the experiment. Increases in strengths were notices in the ten and twenty-five percent soil replacement mixes. The largest increase was approximately thirty-three percent greater than the baseline average.

The results from the forty percent replacement test showed a significant decrease in strengths when comparing against the baseline mix. A loss of about thirty percent was observed between the …

Projectile Impact Effects On A 50 Psi Plug Type Coal Mine Seal, Bruce Albert Von Niederhäusern

Masters Theses

"The current lack of projectile damage criteria for mine seals is assessed to determine if criteria should be developed. Impact experiments were performed on a full-scale 50 psi mine seal to determine failure modes, dynamic stress state, and assess risk to existing operational mine seals. Test projectiles were selected from common underground coal mine items propelled by means of a black powder projectile generator. Projectile velocities attained in testing ranged from approximately 100 to 650 ft/s (30 to 200 m/s). Dynamic strain was measured on the non-impact face to derive the state of stress and estimate failure criteria. Penetration models …