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Full-Text Articles in Engineering

Modeling Leachate Bod And Cod Using Lab-Scale Reactor Landfills And Multiple Linear Regression Analysis, Said Altouqi Jan 2012

Modeling Leachate Bod And Cod Using Lab-Scale Reactor Landfills And Multiple Linear Regression Analysis, Said Altouqi

Civil Engineering Dissertations - Archive

The increasing production of municipal solid waste is a direct consequence of the continuous growth of the world's population and economy. This fact makes protecting the environment against contamination by different kinds of waste a challenging job for engineers and decision makers. Conventional landfilling practices have sometimes failed to protect fresh water resources against leachate contamination as well as the atmosphere against greenhouse gases such as carbon dioxide and methane. Many developed countries have already taken serious steps toward moving to properly engineered, environmental friendly landfills.Landfill leachate contains organic and inorganic pollutants that have been extensively studied in the last …


The Performance Of Irish Grown Timber Composites Under Fire Conditions, Cillian Murphy Jan 2012

The Performance Of Irish Grown Timber Composites Under Fire Conditions, Cillian Murphy

Theses

In comparison with many European countries Ireland does not make the most effective use of its native timber. It is good economic and environmental practice to promote the more efficient utilization of this natural resource. In recent years there has been a revival in the use of timber in multi-storey construction which predominantly utilises load bearing exposed timber composite members. These timber composites are typically manufactured in Europe using European timber.

The current study investigates the viability of using Irish grown timber composites as a direct replacement in these load bearing members. The main areas of focus will be the …


An Analysis Of Dredge Material Reuse Techniques For Ireland, Colm Sheehan Jan 2012

An Analysis Of Dredge Material Reuse Techniques For Ireland, Colm Sheehan

Theses

This thesis examines the use and applicability of a range of dredge material management techniques for the Republic of Ireland which will ultimately assist the stakeholders in the industry in assessing the available dredge material management options. A detailed study is presented into the critical parameters required for successful implementation of a range of dredge material management options. An overview of the Irish dredging industry including current dredge material management practice is presented. This is complemented by a detailed critical analysis of the industry which identifies areas requiring development and future challenges for the dredging industry in Ireland. To further …


Lane Changing Control To Reduce Traffic Load Effect On Long-Span Bridges, Colin C. Caprani, Bernard Enright, Colm Carey Jan 2012

Lane Changing Control To Reduce Traffic Load Effect On Long-Span Bridges, Colin C. Caprani, Bernard Enright, Colm Carey

Conference papers

Long span bridges are critical parts of a nation’s infrastructure network and congested traffic loading is the governing form of traffic loading. Groups of trucks travelling in conveys are created when fast-er moving vehicles, such as cars, change lane. In this research the authors investigate how the control of these lane-changing events can help reduce the traffic load effects on long span bridges. Real traffic data is used to simulate a traffic stream on a virtual road and bridge using a microsimulation model. Various lane-changing restrictions are examined and compared to the typical case of free lane changing. It is …


Estimation Of Lifetime Maximum Distributions Of Bridge Traffic Load Effects, Eugene J. Obrien, Donya Hajializadeh, Emma Sheils, Bernard Enright Jan 2012

Estimation Of Lifetime Maximum Distributions Of Bridge Traffic Load Effects, Eugene J. Obrien, Donya Hajializadeh, Emma Sheils, Bernard Enright

Conference papers

This paper considers the problem of assessing traffic loading on road bridges. A database of European WIM data is used to determine accurate annual maximum distributions of load effect. These in turn are used to find the probability of failure for a number of load effects. Using the probability of failure as the benchmark, traditional measures of safety – factor of safety and reliability index – are reviewed. Both are found to give inconsistent results, i.e., a given factor of safety or reliability index actually corresponds to a range of different probabilities of failure.


Frp Bond Strength Degradation: An Experimental Study Using Pull-Off Testing, Clarisse Mikami Jan 2012

Frp Bond Strength Degradation: An Experimental Study Using Pull-Off Testing, Clarisse Mikami

Wayne State University Theses

ABSTRACT

FRP BOND STRENGTH DEGRADATION: AN EXPERIMENTAL STUDY USING PULL-OFF TESTING

by

CLARISSE MACHADO MIKAMI

December 2012

Advisor: Dr. Hwai-Chung Wu

Major: Civil Engineering

Degree: Master of Science

Fiber reinforced polymer (FRP) is an advanced composite material that has been employed efficiently to rehabilitate deteriorated concrete structures. Environmental factors, however, affect the durability performance of FRP. As bond at the interfacial region between FRP and concrete is essential to the overall integrity of the system, the focus of this thesis is on bond deterioration due to hot weathering conditions.

In this study, an experimental program was developed to investigate the …


Analysis And Modeling Of Roofer And Steel Worker Fall Accidents, Hulya Cakan Jan 2012

Analysis And Modeling Of Roofer And Steel Worker Fall Accidents, Hulya Cakan

Wayne State University Dissertations

" ABSTRACT "

" ANALYSIS AND MODELING OF"

" ROOFER AND STEEL WORKER FALL ACCIDENTS"

by

" Hulya Cakan"

" August 2012"

" Advisor: " Dr. Mumtaz Usmen

" Major: " Civil and Environmental Engineering

" Degree: " Doctor of Philosophy

There are more than nine million construction workers in the US. Roofers and steel workers are the highest risk construction trades according to BLS, and fall from elevation accounts for a large percentage of fatalities and injuries among the construction trades.

In this study, 2114 OSHA accident case reports involving roofers and steel workers were …


Calibration Of Microsimulation Models For Multimodal Freight Networks, Justice Appiah Ph.D., P.E., Bhaven Naik, Scott Sorensen Jan 2012

Calibration Of Microsimulation Models For Multimodal Freight Networks, Justice Appiah Ph.D., P.E., Bhaven Naik, Scott Sorensen

Mid-America Transportation Center: Final Reports and Technical Briefs

This research presents a framework for incorporating the unique operating characteristics of multi-modal freight networks into the calibration process for microscopic traffic simulation models. Because of the nature of heavy freight movements in US DOT Region VII (Nebraska, Iowa, Missouri, Kansas), the focus of the project is on trucks or heavy gross vehicles (HGV). In particular, a genetic algorithm (GA) based optimization technique was developed and used to find optimum parameter values for the vehicle performance model used by “Verkehr In Staedten-SIMulationmodell (VISSIM)”, a widely used microscopic traffic simulation software. At present, the Highway Capacity Manual (HCM), which is the …


Phase I Development Of An Aesthetic, Precast Concrete Bridge Rail, Ronald K. Faller, Scott K. Rosenbaugh, Robert W. Bielenberg, Dean L. Sicking, John D. Reid Jan 2012

Phase I Development Of An Aesthetic, Precast Concrete Bridge Rail, Ronald K. Faller, Scott K. Rosenbaugh, Robert W. Bielenberg, Dean L. Sicking, John D. Reid

Mid-America Transportation Center: Final Reports and Technical Briefs

Precast concrete bridge rail systems offer several advantages over traditional cast-in-place rail designs, including reduced construction time and costs, installation in a wide range of environmental conditions, easier maintenance and repair, improved railing quality, and greater flexibility for aesthetic treatments. The objective of this project was to develop a precast concrete bridge rail system that met the TL-4 impact safety standards provided in MASH. The design criteria for the new bridge rail system included criteria for barrier geometry, provisions for open and closed rail options, constructability, weight limitations, segment length, design impact loads, connection of barrier segments, and connection to …


Truck Safety At Highway-Rail Grade Crossings, Aemal Khattak, Miao Gao Jan 2012

Truck Safety At Highway-Rail Grade Crossings, Aemal Khattak, Miao Gao

Mid-America Transportation Center: Final Reports and Technical Briefs

Safety at highway-rail grade crossings (HRGC) is a major concern for different agencies because increasing highway and rail traffic presents a greater risk of crashes at these locations. In 2008, there were 2,391 crashes and 523 fatalities reported at grade crossings across the U.S. Of these, 187 crashes were reported in Nebraska, including 35 involving trucks with trailers and 10 involving trucks only. At gated crossings, gate-related violations by truck drivers are a primary cause of collisions between trains and trucks. The objectives of this research were to report on the frequency and type of gate violations by truck drivers …


Assessing The Risk Of Crash For Trucks On Onset Yellow, Anuj Sharma Ph.D., Nathaniel P. Burnett Jan 2012

Assessing The Risk Of Crash For Trucks On Onset Yellow, Anuj Sharma Ph.D., Nathaniel P. Burnett

Mid-America Transportation Center: Final Reports and Technical Briefs

Each day, millions of signal changes to the yellow phase occur at isolated high speed intersections, when erroneous driver decisions to stop or go may often lead to a crash. Dilemma zone protection systems are typically used to control these intersections in order to ensure the safe and efficient movement of vehicles. However, traditional dilemma zone protection systems show deterioration in performance during medium to heavy traffic volume conditions, jeopardizing both the safety and efficiency of intersections. The performance of these control systems for heavy vehicles is even more greatly affected, as traditional dilemma zone boundaries were developed for passenger …


Effect Of Freeway Level Of Service And Driver Education On Truck Driver Stress - Phase 1, Anuj Sharma Ph.D., Senem Velipasalar Ph.D., Sanjay Singh M.D., Dave Engel B.S., Sunil Gyawali Ph.D. Jan 2012

Effect Of Freeway Level Of Service And Driver Education On Truck Driver Stress - Phase 1, Anuj Sharma Ph.D., Senem Velipasalar Ph.D., Sanjay Singh M.D., Dave Engel B.S., Sunil Gyawali Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

This research primarily deals with truck driver stress and its nature, stressors, and their mutual relationship. During the study, the different demands of driving that are related to roads, vehicle, traffic conditions, driver predisposition to stress and the surrounding environmental conditions were explored. The two distinct clusters of ―Low Stress level‖ and ―High Stress level‖ were identified in the stress distribution. The binary logistic regression method was used to relate these two conditions of stress with wide range of stressors. The result found that truck driver training was a statistically significant factor in predicting the low stress level. Other statistically …


Intellidrive Technology Based Yellow Onset Decision Assistance System For Trucks, Anuj Sharma Ph.D., Nathaniel Burnett, Sepideh S. Aria Ph.D. Jan 2012

Intellidrive Technology Based Yellow Onset Decision Assistance System For Trucks, Anuj Sharma Ph.D., Nathaniel Burnett, Sepideh S. Aria Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

Erroneous decisions by drivers to stop or go at the onset of yellow can lead to incidences of premature stopping or red light running, which in turn can cause severe rear end or right angle collisions. Because trucks or busses are relatively less maneuverable, have lower available acceleration and lower comfortable deceleration rates, and have a higher line of sight than do passenger vehicles, the risk of crashes is higher for trucks than other vehicles upon stop or go situations. Dilemma zone protection systems are used at high speed intersection s to enhance safety; however, such systems are generally designed …


Cable Median Barrier Failure Analysis And Prevention, Dean L. Sicking, Cody S. Stolle Jan 2012

Cable Median Barrier Failure Analysis And Prevention, Dean L. Sicking, Cody S. Stolle

Mid-America Transportation Center: Final Reports and Technical Briefs

Cross-median crashes have been identified as one of the highest injury or fatality risk crash types. Although crossmedian crashes account for only 2% to 5% of all median crash events, they are disproportionately represented in the number and frequency of fatalities on interstate roadways. Many states have utilized cable median barriers to reduce the risk of cross-median crashes, frequently with great success. However, cable median barriers are also fixed obstacles to errant vehicles. Cable median barriers can place occupants at increased risk of severe injury or fatality if the barrier fails to adequately contain and redirect errant vehicles, resulting in …


Feasibility Of Integrating Natural And Constructed Wetlands In Roadway Drainage System Design, John S. Stansbury, Massom Moussavi, Tian Zhang Jan 2012

Feasibility Of Integrating Natural And Constructed Wetlands In Roadway Drainage System Design, John S. Stansbury, Massom Moussavi, Tian Zhang

Mid-America Transportation Center: Final Reports and Technical Briefs

Stormwater from roadways could have negative effects on the environment and aquatic ecosystems. Typical highway runoff pollutants include solids; heavy metals, particularly cadmium, copper, and zinc; petroleum hydrocarbons; gasoline constituents; PAHs (polyaromatic hydrocarbons); oxygen demanding compounds measured as COD (chemical oxygen demand) and BOD (biochemical oxygen demand); and road salts. Roadway runoff falls under the legislation of the Clean Water Act (CWA) via the National Pollutant Discharge Elimination System (NPDES). CWA regulates discharge of nonpoint source pollutants, such as roadway runoff, by issuing permits to public entities which manage Municipal Separate Storm Sewer Systems (MS4s). Part of the Nebraska Department …


Characteristics And Contributory Causes Related To Large Truck Crashes - Phase Ii, Sundanda Dissanayake Ph.D., P.E., Siddhartha Kotikalapudi Jan 2012

Characteristics And Contributory Causes Related To Large Truck Crashes - Phase Ii, Sundanda Dissanayake Ph.D., P.E., Siddhartha Kotikalapudi

Mid-America Transportation Center: Final Reports and Technical Briefs

Statistics clearly demonstrate that large-truck crashes contribute to a significant percentage of high-severity crashes. It is therefore important for the highway safety community to identify the characteristics and contributory causes of these types of crashes. The first phase of the current research endeavor examined fatal crash data from the Fatality Analysis Reporting System (FARS) database. In the second phase, presented in the current report, truck-crashes of all severity levels were analyzed with the intention of understanding characteristics and contributory causes, as well as identifying factors contributing to increased severity of truck-crashes. This goal could not be achieved by analyzing fatal …


Improving Safety Of The Surface Transportation System By Addressing The Issues Of Vulnerable Road Users: Case Of The Motorcyclists, Sundanda Dissanayake Ph.D., P.E., Mohammad Saad B. Shaheed Jan 2012

Improving Safety Of The Surface Transportation System By Addressing The Issues Of Vulnerable Road Users: Case Of The Motorcyclists, Sundanda Dissanayake Ph.D., P.E., Mohammad Saad B. Shaheed

Mid-America Transportation Center: Final Reports and Technical Briefs

Over the past few years, motorcycle fatalities have increased at an alarming rate in the United States. Motorcycle safety issues in Kansas are no different from the national scenario. Accordingly, this study examines motorcycle crashes in Kansas in order to identify and evaluate critical crash-related factors and subsequent impacts on motorcycle crash injury outcomes. State-level motorcycle rider fatality rates were investigated while considering various factors including helmet laws, using generalized least-squares regression modeling. A detailed characteristic analysis was carried out for motorcycle crashes, using Kansas crash data. Comparisons were made between several aspects of motorcycle crashes and other vehicle crashes. …


Evaluation Of Large Truck Crashes At Horizontal Curves On Two-Lane Rural Highways In Kansas, Eric J. Fitzsimmons Ph.D., Steven Shruck Ph.D., P.E., Tomas E. Lindheimer Jan 2012

Evaluation Of Large Truck Crashes At Horizontal Curves On Two-Lane Rural Highways In Kansas, Eric J. Fitzsimmons Ph.D., Steven Shruck Ph.D., P.E., Tomas E. Lindheimer

Mid-America Transportation Center: Final Reports and Technical Briefs

The objective of this study was to investigate the relationship between roadway and environment-related factors and truck crash severity at horizontal curves located on rural, two-lane state highways in Kansas. Single vehicle truck crashes and multi-vehicle crashes involving at least one truck were extracted from the Kansas Department of Transportation’s crash and roadway databases for the years 2006-2010, resulting in 452 crash records. Descriptive statistics and 95 percent confidence intervals were constructed for an odds ratio analysis comparing single-vehicle truck crashes to multi-vehicle crashes involving at least one truck for the variables that were included in both databases. Overall, the …


A Preliminary Appraisal Of The Safety And Operational Effects On The Regional Transportation System Caused By New Rail- Truck Intermodal Facilities, Thomas E. Mullinazzi, Steven D. Schrock, Eric J. Fitzsimmons, Robert A. Rescot Jan 2012

A Preliminary Appraisal Of The Safety And Operational Effects On The Regional Transportation System Caused By New Rail- Truck Intermodal Facilities, Thomas E. Mullinazzi, Steven D. Schrock, Eric J. Fitzsimmons, Robert A. Rescot

Mid-America Transportation Center: Final Reports and Technical Briefs

Potential for impacts to a small Kansas city were evaluated in light of a planned rail to truck intermodal facility. The city of Edgerton, Kansas, was selected for an intermodal terminal in 2006 by a Class I railroad due to its regional proximity to the Kansas City market and market conditions favorable to such a facility. Through an analysis of various reports and literature along with original traffic, railroad, and environmental data, along with citizen feedback, the framework was laid to be able to compare the impacts of the facility to a snapshot in time prior to its opening.


Earmarked Revenues And Spending Volatility: The Case Of Highway Finance, Phuong Nguyen-Hoang Ph.D., William Duncombe Ph.D. Jan 2012

Earmarked Revenues And Spending Volatility: The Case Of Highway Finance, Phuong Nguyen-Hoang Ph.D., William Duncombe Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

Over the last decade, state governments have experienced two recessions (including the recent “Great Recession”) which have resulted in significant disruptions in state budgets and highlighted the volatility of the personal income tax and general sales tax. Since infrastructure maintenance funding may be particularly vulnerable to budget cuts during recessions, it is important to identify more stable revenue sources and budgetary institutions. One of the distinguishing characteristics of highway finance in the United States is the heavy use of earmarked revenues linked to highway users. Our key research question is whether an increase in the share of highway funding from …


Determining The Stresses In Steel Railroad-Track Rails Due To Freight Movements Using Non-Contact Laser-Speckle, Robert Peterman Ph.D., P.E., Rob Murphy, Weixin Zhao Ph.D. Jan 2012

Determining The Stresses In Steel Railroad-Track Rails Due To Freight Movements Using Non-Contact Laser-Speckle, Robert Peterman Ph.D., P.E., Rob Murphy, Weixin Zhao Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

This research was aimed at developing a procedure to determine the existing stresses in steel rails used in railroad tracks. These stresses are caused by the combination of both thermal restraint and physical/mechanical loads. However, since the track sections are installed at various temperatures and then continuously welded together and secured to wood or concrete ties, the stresses existing in the track at any given time are currently unknown. In fact, not only the magnitude of stress is unknown, but also the basic knowledge about whether the rails are in tension or compression at a given time. Since the stresses …


Inspection Of Earthen Embankment Dams Using Time Lapse Electrical Resistivity Tomography, Jared Stewart Case Jan 2012

Inspection Of Earthen Embankment Dams Using Time Lapse Electrical Resistivity Tomography, Jared Stewart Case

Electronic Theses and Dissertations

According to the National Inventory of Dams (NID), the number of dams across the United States is approximately 85,000. Many of these dams are more than 50 years old and need vast attention to ensure their safety. It is difficult to obtain a full assessment of the dam just by visual inspections alone. This is because many problems associated with dam failure occur internally, which makes it difficult to be observed by the dam inspectors. Examples of these flaws are piping and seepage (flow of water through or around dam walls). It is in this area where geophysical methods can …


Finite Element Modeling Of Seismic Wave Propagation In Earthen Embankments, Binyam Tadese Jan 2012

Finite Element Modeling Of Seismic Wave Propagation In Earthen Embankments, Binyam Tadese

Electronic Theses and Dissertations

The detection of internal seepage zones in embankments (dams and levees) by geophysical seismic techniques such as seismic refraction is limited by a number of factors. Some factors are associated with inversion and smoothing problems during processing, while others are associated with the natural characteristics of embankments and seepage anomalies. In this research, changes in the seismic response associated with: embankment soil compositions and moisture, characteristics of the seepage zone, presence of water in the reservoir, and shape of embankment was studied via 2D and 3D finite element (FE) embankment models. Artificial reflections from external boundaries and numerical dispersion were …


Prediction And Performance Of Single Piles In Clay Soils Under Vibratory Loadings, Domenica Cambio Jan 2012

Prediction And Performance Of Single Piles In Clay Soils Under Vibratory Loadings, Domenica Cambio

Doctoral Dissertations

"This study developed a model for predicting the response, in terms of amplitude versus frequency of single piles under lateral vibratory loadings embedded in clay or fine silty soils. The model incorporates frequency dependent parameters and the effects of soil non-linearity through the relationship between soil shear modulus and damping with strain. A computer program, Dyna5, was used to generate the computed response of single piles using the Novak and El-Shamouby (1983) approach. Soil non-linearity was accounted for by incorporating spline interpolation routine into Dyna5. Sliding and coupled rocking vibrations were addressed. The computed responses were predicted and compared with …


Behavior Of Staged Externally Bonded Carbon Fiber Reinforced Polymer Sheets For Improved Ductility, Laura Marie Rathe Jan 2012

Behavior Of Staged Externally Bonded Carbon Fiber Reinforced Polymer Sheets For Improved Ductility, Laura Marie Rathe

Masters Theses

"Fiber reinforced polymers (FRP) has become increasingly used for the retrofit of aging structures for increased lifespans and for the rapid repair of damaged structures. It has many advantageous such as ease in rapid installation, high strength-to-weight ratio, and corrosion resistance. The main disadvantage of the material is brittle behavior with little warning of impending failures. The main objective of this study is to develop a new system of FRP that exhibits a more ductile behavior. To achieve this objective, separate sheets of FRP were applied at various staged levels and thus engaged at different loads. Ductile behavior was evaluated …


Analysis Of Passive Louver Shading Systems And Impact On Interior Environment, Cory Joseph Brennan Jan 2012

Analysis Of Passive Louver Shading Systems And Impact On Interior Environment, Cory Joseph Brennan

Masters Theses

An installed passive louver shading systems can affect the heating, cooling, and lighting loads of any building, by altering the amount of solar energy, in the form of light and heat, from entering. The benefits of a louver system are derived from the application of solar geometry incident on the site and the climate within the area. By optimizing a passive louver system's design parameters, a building can reduce the total annual energy consumption due to artificial heating, cooling loads and artificial lighting. This research has implemented simulation modeling software, Energy Plus, to predict the effect of passive louver shades …


Effects Of High Volumes Of Fly Ash On Cement Paste, Karl Wehking Beckemeier Jan 2012

Effects Of High Volumes Of Fly Ash On Cement Paste, Karl Wehking Beckemeier

Masters Theses

"The study of high-volume fly ash (HVFA) concrete mixtures has become popular due to the significant environmental and economic benefits which the material may provide. By including fly ash at 50 percent or greater replacement levels, substantial benefits could be obtained. However, the inclusion of fly ash can have negative effects, including incompatibilities between constituents of a mixture. As the fly ash replacement level increases, the degree and likelihood of these problems increases.

In this study, paste mixtures were made, as part of a larger HVFA concrete study, in order to determine the degree to which varying levels of fly …


Characterization Of Soil Variability For Reliability-Based Design, Sitenikechukwu Onyejekwe Jan 2012

Characterization Of Soil Variability For Reliability-Based Design, Sitenikechukwu Onyejekwe

Doctoral Dissertations

"A very carefully planned Missouri-wide field exploration and laboratory investigation program, with a focus on fine-grained soils, was executed with the aim of characterizing the variability of geotechnical parameters statistically with a view to increasing the use of reliability-based design (RBD) among geotechnical engineers. Geotechnical parameters were characterized in terms of both their first and second statistical moments and their coefficient of variation (COV). Their probability distributions and their scale of fluctuation, θ, were also determined. Correlations between difficult-to-obtain parameters and more easily-obtained parameters were developed and the degree of fit of study data to published empirical correlations was investigated. …


Bond, Transfer Length, And Development Length Of Prestressing Strand In Self-Consolidating Concrete, Krista Beth Porterfield Jan 2012

Bond, Transfer Length, And Development Length Of Prestressing Strand In Self-Consolidating Concrete, Krista Beth Porterfield

Masters Theses

"Due to its economic advantages, the use of self-consolidating concrete (SCC) has increased rapidly in recent years. However, because SCC mixes typically have decreased amounts of coarse aggregate and high amounts of admixtures, industry members have expressed concerns that the bond of prestressing strand in SCC may be compromised. While the bond performance of prestressing strand in a new material such as SCC is an important topic requiring investigation, the results are only applicable if the research is completed on strands with similar bond quality as the strands used in the field. Therefore, the objectives of this research program were …


Effects Of High Volume Fly Ash And Powder Activators On Plastic And Hardened Concrete Properties, Drew Alexander Davis Jan 2012

Effects Of High Volume Fly Ash And Powder Activators On Plastic And Hardened Concrete Properties, Drew Alexander Davis

Masters Theses

This study was performed to examine the effects of high volumes of Class C fly ash modified by powder activators upon the plastic and hardened properties of concrete. In a companion study, five Missouri area cements and five Class C fly ashes were examined for incompatibilities, with the most and least reactive combinations being scaled up to full scale concrete testing. Two baseline concrete mixtures were examined, the only difference in mixtures being the sources of portland cement and fly ash. Fly ash replacement was examined at 50% and 70% replacement (by total cementitious mass). Three powder activators were used …