Engineering Commons^™

Mechanism Of Crumb Rubber Modifier Dissolution Into Asphalt Matrix And Its Effect On Final Physical Properties Of Crumb Rubber-Modified Binder, Amir Ghavibazoo, Magdy Abdelrahman, Mohyeldin Ragab

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Modification of asphalt by crumb rubber modifier (CRM) is mostly done through exchange of components between asphalt and CRM. At 160⁰ C and 10 Hz, CRM absorbs aromatics of asphalt and swells; however, at 220⁰ C and 50 Hz, CRM dissolves into the asphalt; this process leads to the release of different components of CRM including carbon black, fillers, and polymeric and oily components. Depending on interaction conditions, CRM dissolution is performed differently, and therefore the state and role of the released components can be different. In this research different mechanisms of dissolution of one size of CRM in asphalt …

Dynamics And Dislodgment From Pore Constrictions Of A Trapped Nonwetting Droplet Stimulated By Seismic Waves, Wen Deng, M. Bayani Cardenas

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Seismic waves affect fluid flow and transport processes in porous media. Therefore, quantitative understanding of the role of seismic waves in subsurface hydrodynamics is important for the development of practical applications and prediction of natural phenomena. We present a theoretical fluid dynamics model to describe how low-frequency elastic waves mobilize isolated droplets trapped in pores by capillary resistance. The ability of the theoretical model to predict the critical mobilization amplitudes (A_c) and the displacement dynamics of the nonwetting droplet are validated against computational fluid dynamics (CFD) simulations. Our theory has the advantage of rapid calculation of A_{c …}

Real Time Bridge Scour Monitoring With Magneto-Inductive Field Coupling, Andriy V. Radchenko, David Pommerenke, Genda Chen, Pratik Maheshwari, Satyajeet R. Shinde, Viswa Pilla, Y. Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

Scour was responsible for most of the U.S. bridges that collapsed during the past 40 years. The maximum scour depth is the most critical parameter in bridge design and maintenance. Due to scouring and refilling of river-bed deposits, existing technologies face a challenge in measuring the maximum scour depth during a strong flood. In this study, a new methodology is proposed for real time scour monitoring of bridges. Smart Rocks with embedded electronics are deployed around the foundation of a bridge as field agents. With wireless communications, these sensors can send their position change information to a nearby mobile station. …

Pore Geometry Effects On Intrapore Viscous To Inertial Flows And On Effective Hydraulic Parameters, Kuldeep Chaudhary, M. Bayani Cardenas, Wen Deng, Philip C. Bennett

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this article, the effects of different diverging-converging pore geometries were investigated, and the microscale fluid flow and effective hydraulic properties from these pores were compared with that of a pipe from viscous to inertial laminar flow regimes. The flow fields are obtained using computational fluid dynamics, and the comparative analysis is based on a new dimensionless hydraulic shape factor β, which is the "specific surface" scaled by the length of pores. Results from all diverging-converging pores show an inverse pattern in velocity and vorticity distributions relative to the pipe flow. The hydraulic conductivity K of all pores is …

Cardinal Raúl Silva Henríquez Bridge During The 2010 Chile Earthquake, Zuocai Wang, Genda Chen, W. Phillip Yen, Ian G. Buckle

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a case study of the Cardinal Raúl Silva Henríquez Bridge, which experienced significant damage during an earthquake that occurred in Chile on February 27, 2010. Supported by reinforced concrete and steel columns of varying heights, the superstructure of the bridge consisted of 22 steel-girder spans, with one intermediate expansion joint located at the middle of the bridge. At each end of the bridge, the bottom flanges of the girders were welded to their bearing steel plates, which were embedded and anchored into the bridge abutment. Two, three-dimensional, finite element models (global versus local) with beam and solid …

Performance Enhancement Of Crumb Rubber-Modified Asphalts Through Control Of The Developed Internal Network Structure, Mohyeldin Ragab, Magdy Abdelrahman, Amir Ghavibzaoo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Control of the internal network structure of crumb rubber-modified asphalt (CRMA) was investigated for its effect on property development in the study presented in this paper. The investigation included evaluation by rheological and interrupted shear tests. Rheological testing involved the monitoring of the changes of the produced complex modulus (G*) and phase angle (δ) for CRMA. In the interrupted shear tests, the shear stress profile for the produced CRMA was investigated. It was found that triggering the critical conditions of the combined interaction of speed, temperature, and time was essential to inducing the formation of the three-dimensional network …

The Guayule Plant: A Renewable, Domestic Source Of Binder Materials For Flexible Pavement Mixtures, David Newton Richardson, Steven Michael Lusher

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Due to the rising price of crude oil, flexible pavement costs have increased significantly. This price pressure has resulted in the increased use of reclaimed asphalt pavement (RAP) and/or reclaimed asphalt roofing shingles (RAS) because of the binder (asphalt cement) they contain. This has increased demand for recycling (rejuvenating) agents which return the RAP/RAS binders to their original state by 1) restoring maltenes (petroleum oils and resins) that have been depleted due to age-hardening/oxidation, and 2) reducing their viscosity. The project concept was to design a flexible pavement mixture (FPM) produced with little-to-no virgin petroleumbased binder which implied the use …

Use Of Ultra-High Performance Concrete To Mitigate Impact And Explosive Threats, Julie Anne Willey

Masters Theses

"This study is a continuation of research conducted by Natalia Carey, Anthony Wulfers, and Dr. John Myers under the DHS ALERT Center. Carey investigated the use of polyurea coating systems to mitigate close range blast threats on wall panels. Wulfers continued this by using both polyurea coatings as well as a sacrificial wood fiber fly ash (WF-FA) layer to try to get increased performance. This research was aimed at the study of ultra-high performance concrete (UHPC) for the use in impact and blast mitigation. There is little information on the performance of UHPC under close range blast loading; therefore it …

Effect Of Crumb Rubber Modifier Dissolution On Storage Stability Of Crumb Rubber-Modified Asphalt, Amir Ghavibazoo, Magdy Abdelrahman, Mohyeldin Ragab

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Crumb rubber-modified asphalt (CRMA) extensively suffers from high-temperature storage instability. Because of the higher density of the crumb rubber modifier (CRM) particles, they settle down to the bottom of storage tanks and cause variation between physical properties of the top and bottom samples. The storage stability of the CRMA changes under different interaction parameters and consequently different mechanisms of interaction. In this research the mechanism of separation under different levels of CRM dissolution was investigated by using Stokes' law. The extent and mechanism of CRM dissolution in asphalt was controlled through regulating interaction temperature and interaction mixing speed. A standard …

Effect Of Mix Parameters On Longevity Of Bituminous Mixtures, Clayton Reichle

Masters Theses

"This study was performed to evaluate the effects of varying aggregate sources, aggregate gradations on the stripping and rutting potential of bituminous based plant mixes specified by the Missouri Department of Transportation. The different aggregate combinations included two different aggregate sources (Potosi Dolomite and Jefferson City Dolomite) including two variations for the Jefferson City Dolomite mix to simulate a marginally in-specification mix and an out-of-specification but in-field tolerance mix. The "field" mix simulated the marginal mix where field tolerance of high dust and low binder content were maximized. All three mixes were evaluated for stripping susceptibility using the Tensile Strength …

Analysis Of Model Uncertainty In Hydraulic Modeling: The Bstem Application To The Osage River, Annabell Leigh Ulary

Masters Theses

"Uncertainty is inevitable when creating any kind of model. A model can be used in the most accurate way possible, if the uncertainties are understood. This study determines the level of uncertainty in the Bank Stability and Toe Erosion Model (BSTEM) of the Osage River downstream of Bagnell Dam between Lake Ozark, MO and Jefferson City, MO. The statistical analysis of the BSTEM model was performed using the aid of SAS statistical computer modeling software. There were 4 different analysis values used to determine the best fit model for all dependent variables. These values include the F-test, the coefficient of …

Modeling Of The Resilient Modulus For Recycled Asphalt Pavement Applications In Base Course Layers, Ehab Noureldin, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The resilient modulus (M_R) is an important parameter for the base course layer in the pavement design process. Use of recycled asphalt pavement (RAP) for this layer must take into consideration the effect of various factors that may occur in the field on the M_R. Previous numerical models used for the granular base layer could be used for the RAP. The study reported here examined the suitability of RAP procedures under the effect of different factors (e.g., water content, dry density, freeze-thaw cycles). Various percentages of the RAP (50%, 75%, and 100% by weight) were employed …

Direct Shear Transfer Of Lightweight Aggregate Concretes With Non-Monolithic Interface Conditions, Dane Michael Shaw

Masters Theses

"This thesis describes the results of a study initiated to examine the influence of concrete unit weight on the direct shear transfer across an interface of concretes cast at different times. This type of interface is common with structural precast concrete connections, such as corbels, for which shear friction design provisions are commonly used. Increasing use of lightweight aggregate concretes prompted this investigation to determine the appropriateness of current shear friction design provisions with respect to all-lightweight and sand-lightweight concrete. The experimental investigation included thirty-six push-off test specimens, each of which was constructed with a cold-joint at the interface shear …

Monitoring Micropile Foundations Of Bridge During Construction, Devin Tavis Dixon

Masters Theses

"Information regarding the load transfer of micropiles during in-service construction has virtually never been monitored or documented. The primary objective of this research project was to monitor the load transfer versus the depth of production micropiles during construction. The micropiles being studied were used to support Bridge No. 2 of the Foothills Parkway in eastern Tennessee during construction. Two of the piers (1 & 2) were instrumented for the purpose of this study. Vibrating wire strain gages (VWSG) were installed on select micropiles within pile groups of twenty (20) micropiles. Seven vibrating wire strain gages were installed on each micropile …

Enamel Coated Steel Reinforcement For Improved Durability And Life-Cycle Performance Of Concrete Structures: Microstructure, Corrosion, And Deterioration, Fujian Tang

Doctoral Dissertations

"This study is aimed (a) to statistically characterize the corrosion-induced deterioration process of reinforced concrete structures (concrete cracking, steel mass loss, and rebar-concrete bond degradation), and (b) to develop and apply three types of enamel-coated steel bars for improved corrosion resistance of the structures. Commercially available pure enamel, mixed enamel with 50% calcium silicate, and double enamel with an inner layer of pure enamel and an outer layer of mixed enamel were considered as various steel coatings. Electrochemical tests were respectively conducted on steel plates, smooth bars embedded in concrete, and deformed bars with/without concrete cover in 3.5 wt.% NaCl …

Field Performance Of Alternative And Cost Efficient Cast In Place And Precast Prestressed Concrete Bridge Approach Slabs, Nathan Price Muncy

Masters Theses

"In December of 2010, the Missouri Department of Transportation (MoDOT) investigated alternative cost-efficient bridge approach slabs (BASs). New BAS designs were subsequently developed and had a projected cost savings up to twenty-four percent with anticipated equal or better structural performance. A precast-prestressed (PCPS) BAS was introduced as an alternative to traditional BASs that offers advantages such as rapid construction and improved long-term durability. The three new BAS designs were implemented into in-situ bridge projects by MoDOT and the field performance was evaluated within this research study.

Field testing of each BAS was performed using two MoDOT HS20 trucks. Various instrumentation …

Shear And Fracture Behavior Of High Performance Concretes, Mahdi Arezoumandi

Doctoral Dissertations

"Concrete is the most widely used man-made material in the world. Like other materials, it has been improved over time. Nowadays, with continued development of science and technology, a new generation of concretes is produced and is termed high performance concretes. A review of previously published work indicates that very few studies (in some cases none) have addressed the structural behavior of full-scale, high performance concrete elements. This study investigated the shear and fracture behavior of two types of high performance concrete - high-volume fly ash concrete (HVFAC) and self-consolidating concrete (SCC). The HVFAC incorporates up to 70% cement replacement …

Numerical Analyses Of Long Carbon Fiber Reinforced Concrete Panels Exposed To Dynamic Loading, Zahra Sadat Tabatabaei

Doctoral Dissertations

"The purpose of this research was to evaluate impact and blast performance of long carbon fiber reinforced concrete experimentally and numerically. Experimental tests were conducted on plain concrete (PC), reinforced concrete, and four different types of long carbon fiber reinforced concrete (LCFRC). The results from each test were then compared to one another. This comparison indicates that adding long carbon fibers to concrete both increases the post-cracking behavior of concrete and decreases the spalls in either an impact or blast test. Among all of the fibers tested, Fiber Type B3 outperformed the other fibers, absorbing more energy during impact. Numerical …