Engineering Commons^™

Analysis Of Loading Rate, Fiber Orientation And Material Composition Through Image Processing And Digital Volume Correlation In High Performance Concrete, Aidan R. Carlson

Electronic Theses and Dissertations

Ultra High Performance Concrete (UHPC) and High Performance concrete (HPC) is characterized by high compressive strength and high toughness. This is achieved through maximizing the particle packing density in the matrix and the use of fibers to reinforce the matrix, increasing the materials toughness. The interactions of fibers and the matrix during loading is quite complex and involves several different energy dissipation mechanisms. The goal of this work and this thesis is to investigate these interactions and identify any changes in material response, and hope that these changes may be useful for the design of UHPC moving forward.

In this …

Examining The Impact Of Centerline Rumble-Strip Installation In Prevention Of Head-On And Opposite Sideswipe Collisions In Maine, Jhan Kevin Gil Marin

Electronic Theses and Dissertations

Among all traffic collisions, lane departure crashes are the leading type of serious traffic crashes in Maine, comprising 72% of state-wide traffic fatalities. To reduce these crashes, Maine Department of Transportation (MaineDOT) installed shoulder and centerline rumble strips on roadways to prevent lane departure crashes in Maine. With a total installed length of 1503 miles of rumble strips, specifically 511 miles of centerline rumble strips in bidirectional and undivided rural two-lane roadways, there is a need to understand the impact of rumble strips in reducing lane departure crashes. In this thesis, observational before-after studies with two methods: comparison group, and …

Investigating The Effect Of Bead Geometry On Fiber Orientation And Thermomechanical Properties For Large-Format Extrusion-Based Additive Manufacturing, Joanna F. Keaton

Electronic Theses and Dissertations

In large-format extrusion-based additive manufacturing of polymer composites, the relationship between material properties and processing parameters requires further investigation. This thesis focuses on the relationship between fiber orientation and thermomechanical properties for short fiber-filled thermoplastic polymer systems manufactured by extrusion-based additive manufacturing. Fiber orientation is particularly important in determining the thermomechanical properties of the composite material as properties in the direction of deposition are expected to be higher for highly aligned fibers than randomly aligned fibers. Fiber orientation distribution, which is related to processing parameters and deposition conditions, can be efficiently represented by the orientation tensor. The orientation tensor can …

Experimental Study On The Behaviour Of A Magnetorheological (Mr) Damper And Evaluation Of Numerical Models, Shelair Sinjari

Electronic Theses and Dissertations

MR dampers are smart dampers that improve structural performance through vibration control. Vibration of tall or flexible structures and structural elements induced by dynamic loads such as wind and earthquakes can cause severe damage to the structure and discomfort for individuals. Therefore, dampers are commonly installed to increase the energy dissipation capacity and mitigate large amplitude vibrations. MR dampers are gaining recognition because of the unique rheological properties offered by the magnetically sensitive MR fluid. Changes to the current level, along with the frequency and amplitude of vibration, affect the force-displacement and force-velocity hysteresis relationship and thus the amount of …

Mechanics And Mechanisms Of Fracture For An Eastern Spruce Subject To Transverse Loading Using Acoustic Emission, Parinaz Belalpour Dastjerdi

Electronic Theses and Dissertations

Due to its excellent structural qualities and accessibility, wood is among the most often utilized structural materials. Despite its ubiquity, wood poses numerous challenges. It is heterogeneous and anisotropic. It has a complex hierarchical ultrastructure, and the properties can have wide variation within a species, and indeed within an individual tree. This work aims to improve our understanding of the strength and fracture behavior of spruce-pine-fir (south) (SPFs), particularly in cross-grain direction. This study’s primary goal is to examine the relationship between crack propagation and cross grain morphology under the following loading configurations: compact tension, compression, and rolling shear. The …

Enzymatic Removal Of Sulfonated Azo Dyes From Synthetic Textile Effluents Using Soybean Peroxidase, Temidayo Oyelere

Electronic Theses and Dissertations

The textile industry and other colour-oriented industries utilize azo dyes in extensive amounts. Dye effluents are recalcitrant to natural biodegradation, hence, causing toxic effects on the environment. Physiochemical treatment generates sludge which requires secondary disposal; advanced oxidation processes (AOPs) are cost and energy intensive; biological methods like anaerobic treatment via bacteria generate aromatic amines which are mutagenic and carcinogenic. A promising alternative that has shown great success in the treatment of wastewater is the enzymatic method. This thesis reports the enzymatic degradation of Reactive Black 5 (RB5), Acid Orange 7 (AO7), and Acid Orange 20 (AO20) from synthetic textile effluents …

Multiscale Evaluation Of The Effect Of Deicing Agents And Environmental Conditions On The Performance Of Asphalt Pavements In Cold Regions, Maryam Mihandoust

Electronic Theses and Dissertations

More than 70% of the United States' roadway network is located in regions subjected to severe winters, resulting in icy pavements that pose safety risks. Winter maintenance operations involving chloride-based deicers such as NaCl, CaCl2, and MgCl2 are essential for ensuring the safety, mobility, and functionality of roads. However, these deicers can lead to diminished pavement durability due to moisture-induced damage. This study examined the effects of these deicers on adhesion evolution and moisture-induced damage mechanisms of asphalt binder-aggregate systems at the macro-, centi-, micro-, and nanoscales. Macro-scale performance characteristics of PG 58-34 hot mix asphalt (HMA) specimens, including rutting, …

An Analysis Of The Effect Of Temperature On Asphalt Paving In South Dakota, S M Rahat Rashedi

Electronic Theses and Dissertations

Temperature is an important parameter to consider for asphalt paving since this work is generally susceptible to weather due to outdoor construction. The South Dakota Department of Transportation (SDDOT) developed working day weather charts in 1998 to address the expected adverse weather days. This thesis investigated the effect of temperature on adverse weather days for asphalt paving and compared them to the value reported in the 1998 SDDOT study. Moreover, the thesis also examined how closely the maximum temperature data from project sites' weekly progress reports (WPR) matched the data from the closest weather stations. When the maximum temperature (TMAX) …

Electrospun Recycled Polyethylene Terephthalate Microfibers As An Asphalt Mix Additive, Debbrata Datta

Electronic Theses and Dissertations

In recent decades, the use of different types of fibers in asphalt has become increasingly popular. Fibers are used in an asphalt mix to improve its durability and resistance against distresses such as rutting and cracking due to repetitive vehicle loading at high temperatures, and low-temperature contraction. Consequently, accurate rheological and performance characterization of asphalt binders and mixes containing fibers is of vital importance. With increased concerns over the environmental disruptions as a result of disposing end-of-life plastics in landfills and the need for improving sustainability of the construction materials, incorporating plastic in construction materials has always been an important …

Nondestructive Evaluation Of Structural Defects In Concrete Slabs, Ehsanul Kabir

Electronic Theses and Dissertations

Nondestructive testing (NDT) is a reliable method for determining the structural integrity of new and old construction and understanding the condition of structural defects. It is widely acknowledged that the interpretation of nondestructive evaluation (NDE) has a significant impact on the reliability and consistency of this technology. However, NDT data acquisition remains subjective and heavily dependent on the operator’s knowledge and expertise. As a result, there are still issues to be resolved regarding the imaging and diagnostic procedures for NDT-based concrete inspection. NDT methods such as ground penetrating radar (GPR), and impact-echo (IE), have been extensively used to inspect concrete …

Implementation Of Ground Penetrating Radar (Gpr) And Complementary Non-Destructive Testing On Concrete Structures, Macy Spears

Electronic Theses and Dissertations

This study analyzes the application and practicality of different non-destructive testing (NDT) methods for the inspection of reinforced concrete. There are two studies discussed in this paper. The first one is a laboratory investigation, utilizing ground penetrating radar (GPR) on concrete slabs that consisted of simulated defects to mimic those found in real concrete structures. This served as a preliminary experiment to verify the GPR data with the design of the slabs. The following study describes a field investigation on an old bridge deck, which involved multiple testing methods. The techniques used were GPR, impact echo (IE), ultrasonic pulse echo …

Predictions Of The Dynamic Complex Modulus Of Non-Conventional Asphalt Concrete Using Machine Learning Techniques, Annie Benson

Electronic Theses and Dissertations

The complex dynamic modulus (|E*|) is a characterization property that defines the stiffness of an asphalt mixture. The dynamic modulus can be found through lab testing or predictions. Since lab testing can be time-consuming and expensive, the prediction method can be used as an alternative method. While a statistical method has been traditionally used for the |E*| prediction such as the Witczak’s predictive equations, machine learning (ML) is recently emerging as an alternative way that |E*| predictions can be made. This research attempted to predict the |E*| using several ML techniques including linear regression, support vector machines (SVM), decision trees, …

Accessing The Relative Sustainability Of Point-Of-Use Water Disinfection Technologies Through Costs And Environmental Impacts, Bright C. Elijah

Electronic Theses and Dissertations

According to the World Health Organization, 785 million people lack access to basic drinking water facilities, and 144 million people rely on surface water which is prone to microbial contamination. Point-of-use (POU) water disinfection technologies can be adopted to help address these issues by treating water at the household level; however, navigating various POU disinfection technologies for a given water source or location can be difficult. While numerous conventional POU technologies exist (e.g., boiling water, POU chlorination), new emerging POU technologies (e.g., using novel materials or advanced processes) have been coined by developers to be lower cost with higher treatment …