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Graduate Program

Research Magazine Fall 2016

LETTER FROM THE DEPARTMENT HEAD Howdy! What an exciting time to be a civil engineer. We’re traversing beyond traditional boundaries in research to discover better ways to serve society and improve the quality of life. One of the most exciting developments for the department is the Center for Infrastructure Renewal, which will house a new high and low bay that is almost four times the size of our current facility. In addition to replacing the materials testing labs, there will be new labs dedicated to interdisciplinary research and outreach for professional education. With new faculty hires, we are expanding research activities into inherently multi-disciplinary areas with autonomous driving vehicles, the use of drones in structural analysis, complex systems for construction and satellite imagery for water resources. We continue to advance improvements to existing structures and roadways, seeking solutions to the pressing concerns for the resiliency and sustainability of the built environment. Faculty seek solutions to unintended consequences of the built environment such as air pollution with multi-generational health impacts, oil spill management effects on the environment, and energy production improvements and the safe disposal of alternative energy waste. These are just a few highlights of the many research endeavors civil engineering faculty members are pursuing. This work would not go very far without the many excellent graduate students and postdoctoral researchers who work with the faculty. While maturing as research experts, several of our doctoral students are also preparing to join academia through the Graduate Teaching Fellow program that has shown significant success in making our graduates more competitive for faculty positions. Innovations frequently occur at the interface of disciplines and we work to create collaborative environments that reach out to other engineering disciplines, the sciences and humanities to holistically approach the many challenges facing the state, nation and world.

Robin Autenrieth, Ph.D., P.E. Department Head and A.P. & Florence Wiley Professor 2

Table of Contents Department facts


New faculty


Cementing societal growth


A relative drop in the ocean


Clean air for our future


Maxing geotechnics applications


Texas hydrological “big picture”


Asphalt sustainability


Autonomous vehicles


Airborne contaminants


Structurally sound


Graduate student spotlights


Graduate Teaching Fellowship


Student participates in FAA program 27 TEXAS A&M The Center forENGINEERING Infrastructure Renewal


The Center for Infrastructure Renewal (CIR) will be a state-of-the-art facility located at the new RELLIS campus. The groundbreaking for this $72 million facility took place Sept. 26. The nearly 140,000 square-foot building has an estimated construction completion date of January 2018. It will be home to large-scale infrastructure testing; aggregate, soil and cement research; autonomous vehicles; and specialized labs for the smart grid, sensor technology, advanced materials and corrosion research. The CIR is a joint venture between two state agencies, the Texas A&M Engineering Experiment Station and the Texas A&M Transportation Institute (TTI). The vision of Dr. Bjorn Birgisson, director of the CIR, is for the center to become the leading global center for developing the new science, engineering and finance solutions for a future sustainable infrastructure. The center will address the need of an increasing demand for more infrastructure for the money than possible with today’s traditional solutions. The center will bring together key stakeholders, including Texas A&M faculty and TTI researchers, industry and government to enable the transformative multidisciplinary infrastructure science and engineering needed for continued future economic growth and competitiveness. The CIR will also develop new ways for rapidly translating new research findings into practice. 3



in civil engineering graduate programs AMONG PUBLIC INSTITUTIONS SOURCE: 2016 U.S. NEWS & WORLD REPORT RANKINGS

232 146


total master’s students

graduate students

total doctoral students FALL 2016 OFFICIAL ENROLLMENT DATA

8 areas

of academic specialization at the graduate level





civil engineering graduate teaching fellows SINCE PROGRAM ESTABLISHMENT IN 2014


The department welcomes three new faculty

Dr. Bjorn Birgisson

The Zachry Department of Civil Engineering at Texas A&M University welcomed a tenured faculty member and two tenure-track faculty members this year. Dr. Bjorn Birgisson joins as TEES Distinguished Research Professor and director of the Center for Infrastructure Renewal and Dr. Ali Mostafavi and Dr. Stephanie Paal join as assistant professors. Prior to joining Texas A&M, Birgisson was a chaired professor of transport science, pro vice-chancellor and the executive dean of the School of Engineering and Applied Science at Aston University in England. Before Aston, Birgisson served as the vice president for research at the KTH Royal Institute of Technology in Stockholm, Sweden, as well as the chaired professor and head of the Division of Highway and Railway Engineering. While with KTH, Birgisson created the Department of Transport Science, blending technology, systems and policy assessment in education and research. His specific areas of specialization include pavement analysis and design, the material science and mechanics of construction materials, non-destructive testing, life cycle analysis and risk assessment. Birgisson was a member of the faculty at the University of Florida, where he earned his tenure in 2004, co-established the Center for Pavements and Infrastructure Materials and the Florida Center for Pavement Excellence, both in 2001. Between 2006 and 2010, Birgisson led the development of the U.S. National Roadmap for Nanotechnology for Concrete-Based Materials. Mostafavi joins the department after having been an assistant professor in the Florida International University College of Engineering and Computing. He received his Ph.D. in civil engineering, and a master’s in industrial administration from the Krannert School of ManagementPurdue University.

Dr. Ali Mostafavi

Dr. Stephanie Paal

His research focuses on a system-of-systems paradigm that bridges the boundaries between complex systems science, network theory and civil infrastructure systems to address sustainability and resilience challenges. He has been a principal investigator on multiple research projects funded by different agencies, such as the National Science Foundation (NSF), Construction Industry Institute (CII) and Miami-Dade Expressway. He is also a member of the Infrastructure Resilience Division of the American Society of Civil Engineers (ASCE) and the Academic Leadership Committee of CII. He has received multiple awards and honors for outstanding research, teaching and service. His recent awards include the CII Distinguished Professor Award, Engineering News Record’s Top 20 under 40 in the Southeast Region and the Best Paper Award of the 2015 ASCE Computing in Civil Engineering Conference. Paal joins the department after having been a postdoctoral researcher in the School of Architecture, Civil and Environmental Engineering at the Swiss Federal Institute of Technology from 2013-2016. She received her doctorate and master’s degrees in civil engineering from Georgia Tech and her bachelor’s degree in architectural engineering from The University of Texas at Austin. Her research interests lie in the study of visualization and advanced technology-based solutions to address infrastructure related challenges. More specifically her interests are related to infrastructure condition assessment, computing technologies and visualization in civil engineering, sensing and data collection for civil infrastructure, systemof-systems resiliency and knowledge extraction and management. She has had extensive experience in creating machine vision methods to automatically assess infrastructure in both post-disaster and routine scenarios. These methods can be used to provide real-time and quantitative assessment of buildings in the damaged state.




Dr. Zachary Grasley Associate Professor & Peter C. Forster Faculty Fellow I 979.845.9965

A society’s socio-economic status depends on the quality of its infrastructure. All of those highways, buildings, and power supplies are structures enabling the technological growth of our society. We all utilize this infrastructure, and we all pay for this infrastructure. If we are paying for this, we want it to last. Beyond lasting, we do not want, for example, to be inconvenienced by lane closures and detours that cause us to sit in bumper-to-bumper traffic, wasting time and money. The majority of this infrastructure is concrete – something we use so much of that it is impossible to substitute another material class for it. There are simply not enough elements in the Earth’s crust to satisfy our demands for infrastructure. While concrete is the most used material in the world after water, what ensures its performance is the key ingredient – the cement paste holding it together. It is this key ingredient that can be improved upon to extend the life of the concrete, saving billions of dollars in maintenance and construction. Research on cement longevity is underway in the Zachry Department of Civil Engineering at Texas A&M University. Dr. Zachary Grasley, associate professor and Peter C. Forster Faculty Fellow I, recently had his paper on the subject published, and recognized as an outstanding paper for 2015, in Materials and Structures. “Making concrete more durable and resilient has enormous societal impacts,” said Grasley. “It will lessen the pressure on finite natural resources needed to meet our growing demand for concrete infrastructure. The models we create help us to understand how and why concrete deforms the way that it does, which gives us insight into how to better engineer its performance.” His research is a combined experimental and modeling approach rooted in fundamental sciences and aimed at improving concrete infrastructure in the United States and around the world. It involves new material development, novel experiments to measure important properties related to durability and resiliency, and advanced models to uncover mechanisms and predict performance of concrete in real structures. “Viscoelastic materials are like the Tempur-Pedic mattress,” said Grasley. “Those materials have a couple of very important characteristics. One is the ‘elastic’ part of that term. It’s reversible, recoverable, and goes back to the way it is supposed to do that. The ‘visco’ part of that term means it comes back slowly. If you leave a column sitting on a concrete surface, gradually you will see that surface sink

under the weight over time. If you can tailor those properties, you can reduce the stress on your concrete, meaning less repair is necessary.” Materials with tailored viscoelastic properties can better absorb an impact or force. If concrete is designed with specific viscoelastic properties, it may delay or even prevent damage from taking place, thereby saving a great deal of money on repair and maintenance. The new materials, experiments and models Grasley’s group is developing will ultimately have wide-ranging applications. They may one day be used for 3-D printing of structures or structural elements or rapid repairs of infrastructure. The experiments could be used for quality control or quality assurance to help improve concrete durability in pavements and bridges. The models may one day be integrated into a design and analysis tool that allows optimized simultaneous structure and material designs. From a materials development perspective, Grasley is currently working on developing rapid hardening concrete intrinsically reinforced with carbon nanofibers. The goal would be to create a crack-resistant concrete that gains strength fast enough to be utilized in minutes rather than days. He has developed a novel, rapid test for measuring concrete permeability, that quantifies how easily water or other liquids can flow through concrete, which is actually porous like a sponge. With respect to modeling, he has worked on advanced material models that couple the evolution of the material structure, and predict the changes as cement chemically reacts with water, the material response to the environment and external loading. His is the first research group to develop a method to adequately disperse high-volume fractions of carbon nanofibers in a cementitious matrix. His research has led to the discovery of new mechanisms of creep — gradual deformation that occurs under constant load — and drying shrinkage. Grasley’s research makes an impact outside his own field of study. Because his research is based on fundamental science rather than empiricism, the models and experiments he has devised have far reaching applications outside of civil engineering. His work with a former Ph.D. student led to the creation of a novel quantification method on how well dispersed nanoparticles are within a composite material. This method is so general that it may be adopted to quantify how well crops are dispersed in a field, or how well dispersed stars are in the sky, the potential applications are limitless. It is impossible to predict where such research might ultimately be utilized. ZACHRY DEPARTMENT OF CIVIL ENGINEERING //




Dr. Scott Socolofsky Professor 979.845.4517


Oil spills can be catastrophic, impacting human and ecosystem health, the ecosystem and the economy. The severity of an oil spill’s impact depends on the amount and source of oil, what courses of action responders choose, and the physical properties of the oil. Research at Texas A&M University has resulted in stronger prediction models that will play a critical role in assessing the pros and cons of tactics used in future spills. The presence of oil in the ocean affects surface and subsurface organisms and resources linked in a complex way, including humans. Damages include that which we see directly impacting wildlife, such as coating birds or mammals with a layer of oil, and the toxicity of the oil itself, which may be poisonous at high enough concentrations. Oil spill research at Texas A&M seeks to mitigate the effects of future spills, predict the hazard conditions under future spill scenarios, and help with decision support in future spills for the response effort. This research takes into consideration the solubility of oil, something previously ignored in past models, which enhances the accuracy of impact on the ecosystem. “With the Texas A&M Oilspill Calculator, TAMOC, we are able to demonstrate the best choices for a blowout model and help to improve model prediction,” said Dr. Scott Socolofsky, professor in the Zachry Department of Civil Engineering. “Better predictions will save resources during the next major subsea blowout by helping to direct the response.” A blowout occurs any time an operator loses control of the flow rate in an oil well pipeline. Blowouts are most likely to occur during drilling of a new oil well since less is known at that time about the characteristics of the oil reservoir. Only in extreme cases do blowouts result in oil spills, as occurred during the Deepwater Horizon accident. Droplet size is one of the most important parameters to consider when viewing spill magnitude, as droplets are transported differently through the vertical plume and encounter the layered density structure of the ocean. Smaller oil droplets are affected by inner ocean turbulence and can become trapped in a horizontal cloud along with other dissolved components released from the well. Both the small droplets and dissolved constituents are degraded by bacteria in the water column. Larger oil droplets rise to the sea surface because the internal ocean turbulence is not strong enough to keep them in a horizontal cloud. “To truly understand the transport, it is necessary to study the characteristics of the turbulence,” said Chris Lai, Ph.D. student. “I measured these velocities and used equations of fluid mechanics to study them. The outcome is a better understanding of the transport mechanisms.”

While it didn’t set out to prove one way or the other, the model confirmed that subsea dispersant use is likely to be an effective mitigation strategy during the phase of the spill before the blowout is contained. The study relies on an assumption about how the dispersant will act, which is based on laboratory experiments (Brandvik et al., 2013). Based on the predictions from several mainstream models, if dispersants are as effective as they were in laboratory experiments, then mainstream models predict that subsea dispersant injection is an effective mitigation strategy during the early phase of a blowout, while containment equipment is being mobilized and installed. Dispersants used are typically surfactants and acts a lot like soap. It helps the oil to “stick” to the water, allowing it to break up into smaller droplets, which are more easily dispersed in the environment. It is pumped directly into the oil and gas flow at the blowout source, ideally about 6 to 12 feet down-hole in the pipeline. It should be applied as soon as a leak to the water column is detected. Some new wells are likely being constructed with the capability to inject dispersant built into the well. When that is not the case, a remotely operated vehicle must be used to inject the dispersant from a pipeline from a supply ship. When considering trade-offs, one has to remember that an oil spill is already a bad event for the environment. The choice to use dispersants is made whenever they will reduce exposure of toxic oil compounds to people. People usually encounter oil through fumes in the air, oil on the coast or oil on the sea surface. Subsea dispersant injection reduces oil residue in the air, coast and surface. “The EPA’s first line of decision making is to protect human health,” said Socolofsky. “Dispersant injection did do that during the Deepwater Horizon accident and would still be selected today if human health would be protected. An unfortunate trade-off is that the oil still enters the environment, and in the case of subsea dispersant injecting, impacts more of the ocean water column and seafloor than if dispersants were not used.” The group conducted the model intercomparison study, built the model, conducted extensive laboratory experiments and participated in two major field experiments to study natural seeps. Each of these aspects has been published in different papers. The TAMOC model is being used by the U.S. National Oceanographic and Atmospheric Administration (NOAA) in its oil spill model GNOME (General NOAA Operational Modeling Environment). The team is also working with NOAA to predict what might happen for an accidental blowout in the Arctic. ZACHRY DEPARTMENT OF CIVIL ENGINEERING //




Dr. Qi Ying Associate Professor 979.845.9709


Preterm birth is the leading cause of infant death and long-term neurological disease, and 1 in 10 infants born in the United States is affected by preterm birth according to the Centers for Disease Control and Prevention. The increasing public health threat of air pollution may be correlated to an increased risk of preterm birth. Researchers at Texas A&M University, including Dr. Qi Ying, associate professor in the Zachry Department of Civil Engineering, are in collaboration with the National Institute of Child Health and Human Development (NICHD), seeking to improve the understanding of the connection between air pollution exposure and the health of pregnant women and their newborns.

These simulated concentration levels were used to approximate the exposure of about 200,000 women to these pollutants during the full course of their pregnancy. The major conclusion of this study was that mothers with asthma may experience a higher risk for preterm birth after being exposed to traffic related pollutants like carbon monoxide and nitrous oxides during their pregnancy. The risk is particularly associated with exposure in the early months of pregnancy and just before conception.

By developing an advanced air quality model providing solid statistical analyses that clarifies and quantifies this relationship, this research is removing a major obstacle for environmental epidemiologists studying this field.

It has long been suspected that air pollution could increase preterm birth risk, however the high temporal and spatial resolution of the data produced by this new model allowed researchers to more accurately determine the most critical window of time when exposure can influence the risk of preterm birth.

Epidemiologists had been attempting to define this issue using insufficiently representative air pollution data that lacked time and spatial resolution. Most of their studies on the matter relied on inadequate data from central monitors that could neither sufficiently represent the spatial and temporal variation of air pollutants nor monitor a wide enough range of species. To solve this problem, a team of researchers at Texas A&M has developed stateof-the-art improvements to the existing EPA air quality models to predict the concentrations of a large number of gaseous and particulate pollutants at a very high spatial and temporal resolution. That is, models with improved visual clarity and precision in regards to time. The specific model used for this project predicts a wide range of pollutants based on their estimated emission rates from the hundreds of different emission sources and the physical and chemical processes of air pollutants in the atmosphere.

“These findings set the stage for further studies designed to help prevent preterm birth in this at-risk group,” says Mendola.

These models produced by researchers and executed by the supercomputers at Texas A&M will be highly influential in the understanding of the effect of air pollution on public health. The results from these studies, as well as studies that will be made possible with this model, will allow the public, as well as policy makers, to understand and make informed decisions on emissions control. Public policy limiting air pollution through emission control could potentially protect the health of people worldwide in areas of unsatisfactory air quality. The results of this study were published and can be found in the Journal of Allergy and Clinical Immunology.

Ying is a major contributor to this research and serves as the principal investigator (PI) of the air quality modeling aspect of the “Air Quality and Reproductive Health,” project with Dr. Pauline Mendola of the NICHD, who oversees the project as primary PI. “A unique feature of many of our models is the capability to quantitatively determine the contributions of different sources to overall pollutant concentrations,” says Ying. “We applied our model to simulate the concentrations of particulate matter, ozone, nitrogen oxides, sulfur dioxide and carbon monoxide at ground level over the entire continental United States from 2001 to 2009.”





Dr. Marcelo Sanchez Associate Professor 979.862.6604


Dr. Marcelo Sanchez, associate professor in the Zachry Department of Civil Engineering at Texas A&M University, and his team of researchers are paving the way for new engineering applications that will shape the future of energy production and storage. From new possibilities in geothermal and hydrocarbon resources to better storage applications for nuclear energy, the implications of this research are exciting and far reaching. Although soils and rocks are hardly viewed as groundbreaking, exploring the untapped potential of geomaterials like these is the primary goal of Sanchez and his team. The team is studying the behavior of geomaterials under complex conditions involving thermal, hydraulic, mechanical and geochemical actions. Through the team’s research it hopes to make possible both the production of new energy sources and also the safe storage of nuclear waste. This field of study, known as geotechnics, is particularly important because of the increase in future energy demands associated with economic development and population growth worldwide. This type of research plays a crucial role in the continuing development of the design of nuclear waste repositories, advancing the design of geological carbon-dioxide sequestration and enhanced geothermal systems, and assisting energy production from existing and new sources. The interest in these applications is relatively new, so the response of soils and rocks in extreme environments was not well known prior to recent progress in research. The team from Texas A&M has contributed with new experimental evidence and advanced numerical models to expand the previously limited range of existing knowledge in this area. Previous models in this field have disregarded the effect of the material fabric on the analyses involving geomaterials subjected to extreme circumstances. This cannot be considered valid, however, when dealing with complex geomaterials like expansive clays, hydrate bearing sediments and fractured soils and rocks. The research conducted by Sanchez and his team focuses on enhancing the capability of the existing tools by incorporating the details of micro-scale geomaterial into the macroscopic models. By inserting the microscopic details, the researchers have been able to begin bridging the gap between micro-scale geomaterial behaviors and macro-scale engineering problems like storing nuclear waste, producing geothermal energy and more. The numerical models produced at Texas A&M have been recognized for their advanced and vigorous approaches that explicitly consider both the micro- and macro-scale structures in clayed materials.

In addition to these advances, the team has also developed a state-of-the-art model for sediments containing gas hydrates and proposed a novel numerical technique to model pre-existing and evolving cracks in geomaterials. The challenges created by the ever-increasing demand for energy solutions, as well as for resilient and sustainable civil infrastructure, continuously expand the need for more advanced knowledge of soil and rock behaviors. Driven by these societal needs and the engineering applications associated with them, the researchers at Texas A&M painstakingly study the response of geomaterials subjected to unprecedented solicitations. This involves researching high thermal gradients, very large fluid pressures, and significant confinement stresses. Thermal gradients involve heat shocks above 400 degrees Fahrenheit investigated in geothermal and nuclear waste disposal related applications. The fluid pressure studies consist of pressures above 25 mega pascal, which is approximately 247 times regular atmospheric pressure. High confinement applications are vast, from nuclear waste disposal to truly anything located deep in the ground requiring high stress. “Geomechanics is at the core of the modern infrastructure and energy challenges and our group is working hard to keep Texas A&M at the forefront of the research advances,� said Sanchez.

Repository for nuclear waste (Courtesy of ANDRA)

Enhanced geothermal systems

(courtesy of U.S. Department of Energy)





Dr. Huilin Gao Assistant Professor 979.845.2875

Mother Nature can throw out some devastating situations that leave us feeling helpless and unprepared. Living in a diverse ecosystem like Texas, which is prone to extremes of drought and flood, it is important to have comprehensive models that educate key decision makers on important socioeconomic impacts. Dr. Huilin Gao, assistant professor in the Zachry Department of Civil Engineering at Texas A&M University, is researching two interrelated areas of water resource modeling. Her research seeks to understand and predict the effects of climate change, urbanization and reservoir flow regulation on streamflow and future water management. With a fast-growing population and continuous land cover change, it is important to understand the consequent altered streamflow and explore strategies to better manage our limited water resources. Through numerical modeling of these processes and water management, as well as satellite remote sensing of lakes, reservoirs, rivers and coastal water bodies, Gao aims to create a systematic big picture view of Texas’ hydrological processes. The model could be used to assist with mitigating flood and drought affects, especially beneficial to the social-economic development of the State of Texas. Chlorophyll-a, an indicator of algae biomass production resulting from nutrient influx to waterways, can be used for evaluating ecosystem health under environmental stressors. The use of satellite remote sensing to monitor Chlorophyll-a concentrations across the bay will help both coastal management agencies and stakeholders stay well informed of eutrophication and harmful algae bloom conditions. Gao’s research consistently combines multiple disciplines to foster new perspectives into these dynamic processes, which will help close existing knowledge gaps. This approach will also seamlessly link the projected landuse changes on upstream river basins to the forecasting of coastal ecosystem productivity.

“I am working on modeling streamflow and water availability over Texas river basins under various changing scenarios, and investigating the relationship between freshwater inflow and phytoplankton productivity over coastal regions,” said Gao. “From this research, we can set up a prototype for the seasonal forecasting of phytoplankton productivity over the Galveston Bay.” By creating new knowledge and filling in key knowledge gaps, this interdisciplinary study will provide decision makers with a powerful tool to understand the interactions among climate change, urbanization, flow regulation and ecosystem sustainability. The results are especially meaningful for protecting coastal ecosystems and supporting the fishing industry. Through her NSF CAREER grant, Gao has been working with high school teachers through the college of engineering’s Enrichment Experiences in Engineering and Undergraduate Summer Research Grant programs, as well as assisting with water resources activities in the department’s Camp BUILD high school outreach summer camp. Graduate students are funded to carry out research and interact with the teachers, high school students and undergraduates who visit the lab over the summer. “This study makes a priceless contribution in the area of education,” said Gao. “We are really proud of the various educational activities involving high school, undergraduate and graduate students.” The research, Urbanization and Climate Change Effects on Peakflow in the San Antonio River Basin, has been accepted by the Journal of Hydrometeorology.

The team has used a physically-based, fully-distributed hydrological model to investigate how urbanization and climate change will affect the peak streamflow over the San Antonio River Basin. It has also integrated a reservoir module into the hydrological model such that flow regulation options can be explored for promoting water resilience. Furthermore, the team has created a remotely sensed Chlorophyll-a product — which provides better spatial and temporal coverage than the traditional sampling approach — for studying the inflow to Chlorophyll-a relationship across Galveston Bay. 15



Dr. Amy Epps Martin Professor and A.P. & Florence Wiley Faculty Fellow 979.862.1750

Ongoing research at Texas A&M University is looking at increasing the use of recycled materials in asphalt pavements — including recycled asphalt shingles (RAS) and reclaimed asphalt pavement (RAP) — which is the most recycled and reused material in the United States at a rate of more than 99 percent according to the National Asphalt Pavement Association (NAPA). By recycling and reusing RAP and RAS in asphalt pavements, millions of barrels of asphalt binder and millions of tons of natural aggregates are conserved. NAPA reports about $2.8 billion saved in 2013 when utilizing reclaimed and reused asphalt binder materials, versus the use of virgin material.

It is expected that this method and an associated set of guidelines for characterizing binder blends and mixtures will be used throughout the asphalt industry as RAP and RAS usage grows. Moving forward, the research will be exploring the relationship between rheological properties that control cracking performance and chemical properties that evolve with aging. Epps Martin has also incorporated some of the recent research results into civil engineering courses taught at Texas A&M.

Dr. Amy Epps Martin, professor and A.P. & Florence Wiley Faculty Fellow in the Zachry Department of Civil Engineering, is the principal investigator on National Cooperative Highway Research Program sponsored project 9-58 (NCHRP 9-58): the effects of rejuvenating agents on asphalt mixtures with high RAS and RAP binder ratios. Her team at Texas A&M also includes two researchers from the Texas A&M Transportation Institute (TTI), a post-doctoral researcher, a Ph.D. student and two undergraduate students. This $1.5M national research project includes TTI, the University of Nevada, Reno, the University of New Hampshire and a consultant. The project focuses on the effects of rejuvenating agents on asphalt mixtures with high recycled materials content. NCHRP 9-58 is evaluating if higher recycled binder ratios (RBRs) up to 0.5 can be utilized if rejuvenating agents are used. Rejuvenating agents include a variety of materials including some green alternatives such as vegetable and other bio-based oils. “Asphalt mixtures age by oxidation and become brittle and prone to cracking, which is why we add the rejuvenating agents to partially restore their properties,” said Epps Martin. “Through our research, we have defined their effectiveness and its evolution to capture the effects of rejuvenating agents with aging on binder and mixture cracking resistance.” The research team has developed a method for selecting the dosage of the rejuvenating agent to restore the performance grade to a target grade required by the climate and traffic in a specific project location. They have also extended this method to consider a binder performance index called ΔTc that indicates the brittleness or susceptibility to cracking for a specific binder blend that includes a virgin binder, a binder recycled from the RAP and RAS, and the rejuvenating agent.






Dr. Alireza Talebpour Assistant Professor 979.845.0875

You’ve seen them in futuristic science fiction movies for decades, but the reality is that unmanned vehicles are just around the corner, quite literally. Fully automated vehicles are expected to hit the roads as early as 2018. In the meantime, you might catch the Zachry Department of Civil Engineering’s autonomous vehicle research car, donated in full by the Sterling Auto Group in Bryan, cruising around the Texas A&M University campus. This vehicle will be used to investigate interactions and reactions between automated and regular vehicles, and pedestrians to this technology. “Not only will our driving environment change drastically, but we can expect the interaction between automated and regular vehicles to be different from the interaction between regular vehicles,” said Dr. Alireza Talebpour, assistant professor in the Zachry Department of Civil Engineering. “There will be a wealth of possible changes to foresee and acclimate ourselves to before automated vehicles can fully integrate.” The impact of this technology is expected to reach far beyond the transportation systems, impacting our daily lives with changes in driving habits, vehicular movements and safety. Research at the Smart City Lab in the civil engineering department focuses on understanding the interactions between regular vehicles, connected vehicles, automated vehicles and pedestrians on the roads, as well as investigating the effects of these interactions on congestion, safety, emissions, and energy consumption. “How people move in the built environment has determined the design and orientation of buildings, roadways, and most of urban and suburban developments,” said Dr. Robin Autenrieth, department head of civil engineering. “With the introduction of automated and connected vehicles, there could be significant changes to the infrastructure beyond the obvious.” With the introduction of automated vehicles into daily commuting, many scenarios will arise that need to be anticipated. Automated vehicles will be capable of following other vehicles more closely at distances that are considered unsafe for manned vehicles. This close following feature of automated vehicles will also impact the capacity and efficiency of our roads. Less congestion reduces the travel cost, which in turn may increase travelers and impact longevity of the infrastructure.

A major part of this research will focus on pattern recognition and data visualization, collected on the Texas A&M campus. This data will aid in understanding the underlying behavioral patterns necessary for equipping automated vehicles for safety and efficiency. The United States Department of Transportation has identified five levels of automation, where level zero corresponds to no automation and level four corresponds to fully automated vehicles. At level four automation, there is no need for a driver and the vehicle can handle all necessary maneuvers from origin to destination. Unfortunately, the limited understanding of driver behavior in a mixed, regular and automated environment prevents the production of level four automated vehicles. Therefore, the current focus of the technology and car industries, with few exceptions, is on level three. At level three automation, the vehicle can handle nearly all maneuvers from origin to destination; however, the presence of a driver is necessary to take over the driving task and handle unexpected and challenging driving maneuvers. Transition from automated to regular driving is one of the biggest challenges. Research is being conducted on developing a reliable mechanism to provide a safe and efficient transition from automated to regular driving. “This is an exciting time in the transportation and automotive industry with how quickly transportation is changing,” said Michael Gonzalez, sales operations manager at Sterling Auto Group. “To be a part of the future, supporting this research in our backyard, is a great opportunity for our dealership. We look forward to seeing how this develops and the impacts on the university and the community.” In addition to the donation from Sterling Auto Group, the Texas A&M University System and the Texas A&M Engineering Experiment Station (TEES) provided start-up funds for this research area.





Dr. Shankar Chellam J. Walter “Deak” Porter ’22 & James W. “Bud” Porter ’51 Professor 979.458.5914

“A breath of fresh air” is a common saying, used to signify something cleansing and refreshing. But what if that air isn’t as clean as you think? In fact, what one researcher with the Zachry Department of Civil Engineering at Texas A&M University has found in the air may surprise you. Even more surprising are the applications of this finding, and how it can improve our lives.

the common sources of pollution in major metropolitan areas of Texas, the researchers developed unique metal signatures for various industrial and natural sources of aerosols, and then collected samples from different locations and determined whether there were signatures of the various sources in the these samples.

“That Saharan dust pollutes Texas’ air was a completely serendipitous finding while investigating the amount of man-made, locally-sourced pollutants,” said Dr. Shankar Chellam, professor in the civil engineering department and faculty lead for the Aerosols & Water Treatment Lab. “When we think pollution in urban areas like Houston, we are programmed to place full blame on industry when really there are other unexpected, natural factors. This research can be used to adjust and regulate man-made pollutants in order to increase our quality of air.”

Through their efforts, it is now possible to isolate, identify and quantify petroleum refinery, vehicular and desert dust impacts on urban air quality. This was achieved through developing novel analytical techniques to measure platinum, palladium, rhodium and rare earth elements, along with a wide range of other metals in the atmosphere.

The average person breathes over 3,000 gallons of air each day, and breathing contaminated air can lead to a wealth of health issues ranging from irritated eyes to cancer, depending on the fine particles floating around. Reducing air pollution became a priority of the government in 1970 with the creation of the Environmental Protection Agency, which makes it its business to clean up air pollution in the country along with industry, local and state government and environmental groups.

Applications from this research could play a vital role in regulating air quality, impacting large industries all the way down to vehicle users. The findings can be used for the objective measurement of industrial and natural particulate emissions and the development of better science-based policies or regulations. For more information, visit

Ongoing research at Texas A&M joins in this battle against an unseen enemy, choosing to focus on finding the myriad sources of fine particles in ambient air that we breathe. We want to know what the various sources are and what the particles are made of, that way someone else can take the findings and create policies and take action. Key problems the team targets include the long-range transport of mineral dust from the Sahara and Middle East deserts and its impact on air quality in urban areas; particulate matter emissions from light-duty vehicles; and particle releases from petroleum refining operations. “Pollution can be transported all over; it’s a mixed media that spreads and affects all,” said Ayse Bozlaker, a postdoctoral researcher working with Chellam. “We saw the need to quantify pollution caused by natural sources, something we cannot control, thus helping us to regulate man-made pollution and clean up our overall air quality.” Expecting pollution to emanate from oil refineries and motor vehicles, two of





Dr. Stefan Hurlebaus Professor 979.845.9570 22


Infrastructure can deteriorate by being exposed to extreme events, such as earthquakes and hurricanes, or naturally from corrosion and fatigue. Our economy necessitates the demand to maximize the efficiency of existing civil infrastructure components, without compromising safety and reliability. “In order to achieve the goal of high structural reliability and safety, it is necessary to either reduce the impact of extreme loads on the structure or better assess the structural integrity,” said Dr. Stefan Hurlebaus, professor in the Zachry Department of Civil Engineering at Texas A&M University. Hurlebaus’ research focuses on the development of smart structures, complete with integrated sensors that provide health monitoring, and measurable testing that is not harmful to the structure in the process. His work directly impacts the safety and reliability of infrastructure by developing better diagnostic techniques including innovative mitigation measures that prevent failures due to fatigue and fracture, and smart structures preventing damages from extreme events. His research team develops nondestructive testing methods, as well as utilizes methods that are already commercially available to determine if the integrity of a structure is known in sufficient detail. This knowledge allows field workers to identify the appropriate maintenance, rehabilitation or preservation methods to apply to the structure. This can increase the sustainability of a structure, resulting in cost savings. The assessment of structural integrity is done by nondestructive testing which benefits the structure by being a continuous, in-service assessment that allows structures to be operated beyond their design lives. This results in cost-savings by avoiding repair work or replacing the structure altogether. “We have several test structures such as concrete slabs, a bridge girder and a stay cable system that include artificial defects,” said Hurlebaus. “With those results, we are able to identify the best testing technique suitable for a specific type of defect.” The research program operates out of a state-of-the-art sensors laboratory where the team has developed an understanding of wide-ranging physical phenomena, resulting in many significant contributions.




Iman Shafii is a civil engineering Ph.D. student specializing in geotechnical engineering. Shafii received his bachelor’s degree in civil engineering from Sharif University in Iran, and his master’s in geotechnical engineering from Southern Illinois University Edwardsville. After graduating from Illinois, Shafii aspired to study with the most well-known and respected professors in the field of geotechnical engineering, which led him to Texas A&M.

Iman Shafii Ph.D. student



Geotechnical Engineering


Shafii works with Dr. JeanLouis Briaud as a graduate assistant researching erosion resistance of soils for the National Cooperative Highway Research Program. His research will provide information regarding

different types of soil and their resistance to erosion beneath any type of structure and how this may change in different conditions. His research will be useful to a wide variety of organizations, and has the potential to have a wide-reaching impact. “Civil engineering happens everywhere in the world,” he said. “Within any area of it, people are always needed. Something is going to need to be built, repaired, or renewed. Find what you love to do, your main interest, and go for it.” Shafii came to A&M in the fall of 2015 and will graduate with a Ph.D. in geotechnical engineering in May 2018.

Ayu Sari Ph.D. student



Environmental Engineering

Ayu Sari is a civil engineering Ph.D. student specializing in environmental engineering. Sari graduated with a bachelor’s in chemical engineering from the University of Houston and came to Texas A&M for her graduate studies. Sari’s older brother, a chemical engineer with a focus in water, encouraged her to pursue environmental engineering with a focus in wastewater and water treatment. In Indonesia, potable water is hard to come by which inspired Sari to pursue water treatment. Sari came to Texas A&M because she wanted to continue her studies with Dr.

Shankar Chellam, who she also worked with in Houston. While at Texas A&M, Sari has been involved in the North American Membrane Society and the American Institute of Chemical Engineers, and has competed in American Water Works Associations competitions where she qualified for nationals both in 2013 and 2015.

student you want your research and knowledge to be spread around the world.

As a Ph.D. student, Sari has published in peer-reviewed journals three times, and currently has another article in the submission process. Her most notable accomplishments as a student are having her articles published because as a Ph.D.

“You’ll never feel alone with the culture here,” she said. “Everyone is so helpful, especially the faculty of the civil engineering department.”

Above all, Sari values the Aggie Network, saying that as an Aggie you never really leave A&M in spirit even after you graduate. She fondly speaks of the Aggie family she has become a part of.



Graduate Teaching Fellowship Program The Graduate Teaching Fellows (GTF) Program in the Texas A&M University College of Engineering is a competitive program that prepares and encourages doctoral students to pursue academic careers. This program gives students interested in an academic career the opportunity to compete for faculty positions at top tier universities. In order to facilitate the transition from student to teacher, students gain experience from a supervised teaching role while continuing their doctoral research and professional activities. Fellowship recipients prepare and deliver lectures, prepare a syllabus, hold office hours, offer help sessions when needed, prepare homework problems, supervise grading of homework, proctor and grade quizzes, tests, and the final exam, assign grades, and prepare a detailed end-of-semester report to the departmental coordinator and director. This format exposes the nominated students to the expectations of engineering faculty at the assistant professor level, such as teaching excellence and establishing an independent research record. The college chose to expand the program that originated in the Zachry Department of Civil Engineering, offering this opportunity to all engineering Ph.D. candidates. Since the establishment of this program, the civil engineering department has witnessed firsthand the success of many doctoral students in academia after their completion of the teaching fellows program and their graduation from Texas A&M.

Michelle L. Bernhardt, Ph.D. ’08

Bernhardt earned her bachelor’s, master’s, and doctoral degrees from Texas A&M in 2008, 2009 and 2013, respectively. As a Ph.D. candidate, Bernhardt joined the GTF program hoping to gain valuable experience in teaching while being mentored along the way. After finishing her Ph.D., Bernhardt was hired as an assistant professor at the University of Arkansas. She says that this program was one of the most valuable opportunities she had in graduate school in terms of preparing for a career in academia. “I cannot imagine what that first semester would have been like without having some prior experience in the classroom,” said Bernhardt. “The program allowed me to hit the ground running in my new position.” Before the program began, Bernhardt admits she was anxious about entering teaching directly after graduation with no prior experience. After only a few weeks in the GTF program, she was hooked. She attributes her decision to become a professor to the program and its mentors. Bernhardt is now an assistant professor in the Department of Civil Engineering at the University of Arkansas. She conducts research focused on the behavior of granular material and she also currently advises and mentors a postdoctoral researcher, five graduate researchers and two undergraduate researchers. She teaches undergraduate and graduate classes in geotechnical engineering. 26

Amy Kim, Ph.D. ’13

Kim received her Ph.D. from the department in 2013. Prior to attending Texas A&M, Kim received her bachelor’s degree in architectural studies from the University of Illinois at Urbana-Champaign and she earned a master’s degree in civil engineering at Illinois Institute of Technology. Prior to beginning her doctoral program at Texas A&M, Kim worked as a construction engineer for over eight years. In her time in the GTF program Kim was hoping to gain valuable experience and insight into the profession of academia. “It taught me just how much work goes into preparing a valuable and meaningful lecture,” said Kim. “This opportunity solidified my passion for teaching and encouraged me to pursue an academic career.” Kim is now an assistant professor in the Department of Civil and Environmental Engineering at the University of Washington. In addition to teaching multiple undergraduate civil engineering courses, Kim conducts research on reducing energy consumption for the built environment with emerging materials and technologies, construction management issues for transportation projects, long-range strategic issues affecting preservation, maintenance and renewal of highway infrastructure, and developing a comprehensive and scalable scoping process to assist transportation agencies to improve on-time and on-budget delivery of highway projects.

Ph.D. student participates in Federal Administration TEXAS A&M ENGINEERING fellowship program Cassandra Rutherford, Ph.D. ’02

Rutherford was the first student to participate in the GTF program, graduating with her Ph.D. in 2011. She encouraged the department to set up a formal program that allowed students to apply their technical knowledge and build their teaching skills through a faculty-mentored teaching experience. “The program provided me with invaluable experience organizing a course, preparing for lectures and applying classroom teaching techniques with a faculty member who provided high quality teaching assessments,” said Rutherford. She currently holds a position at the University of Illinois at UrbanaChampaign as an assistant professor of geotechnical engineering. In addition to teaching both undergraduate and graduate level courses, her research group investigates the characterization of marine sediments subjected to dynamic loading and the relationship between geohazard triggering mechanisms and sediment properties. Her research contributes to the development of offshore foundations such as wind turbine structures and subsea oil production structures. Rutherford is an American Society of Civil Engineers Excellence in Civil Engineering Education Fellow and an Academy of Excellence in Engineering Education Fellow for the college of engineering at the University of Illinois.

Stacey Tucker-Kulesza, Ph.D. ’08

Tucker-Kulesza graduated from Texas A&M University with a bachelor’s degree in civil engineering in 2008, and also earned her master’s degree and Ph.D. in geotechnical engineering in 2009 and 2013, respectively. She is currently an assistant professor at Kansas State University. Tucker-Kulesza’s research focuses on nondestructive testing and monitoring of deteriorating infrastructure, geophysical testing, and soil erosion potential with a goal of understanding the in situ integrity of both aging infrastructure and natural materials in order to support the global initiative of sustainability. In addition to her ongoing research, she teaches three courses a year: an undergraduate soil mechanics course and two graduate courses in geotechnical engineering. She credits the GTF program with teaching her how to manage the balance between teaching and research, which she found to be immensely helpful when beginning her professional academic career.

Atish Nadkarni, Ph.D. student in the Zachry Department of Civil Engineering at Texas A&M University, was selected to participate in the inaugural Partnership to Enhance General Aviation Safety, Accessibility, and Sustainability (PEGASAS) and the Center of Excellence Fellowship, a program created by the Federal Aviation Administration. The mission of PEGASAS is to enhance general aviation safety, accessibility and sustainability through a world-class network of partnerships. Texas A&M is one of six core members of PEGASAS, and one of only three members that operates its own airport. Nadkarni worked full-time as a graduate research assistant over the summer at the William J. Hughes Technical Center in Atlantic City, New Jersey. The research he participated in considered different combinations of various asphalt-concrete mix designs and types of tar that could be used to best withstand the increased tire pressures of newer aircrafts, such as the Boeing B787 and Airbus A350, that are damaging existing taxiways and runways. During the fellowship, Nadkarni studied at the accelerated pavement testing facility and worked with state of the art equipment like heavy load simulators at the National Airport Pavement and Materials Research Center. He also worked with FAA technical experts to gain insight from their expertise of the equipment and analytical tools used by the FAA. All of this contributed to his research on the effect of material types, binder types and tire pressure on asphalt strains. The research and information

Nadkarni collected will support his doctoral and grant research at Texas A&M. “Having worked in this facility, I am much more confident in approaching professionals in my area with profound knowledge and expertise, and aiming to learn the most that I can from them,” said Nadkarni. Nadkarni is from Goa, India, where he received his bachelor’s degree in civil engineering. He attained his master’s from Arizona State University in 2007. His doctoral research studies rutting and cracking characterization in the modeling of asphalt concrete pavement materials and soils. This involves the concepts of viscoelasticity, viscoplasticity, related theories, and continuum mechanics. The pavements he studies include highways, airport runways and taxiways. Nadkarni currently studies under Dr. Dallas Little, Snead Chair Professor and Regents Professor in the civil engineering department. After earning his Ph. D., Nadkarni hopes to begin a career as a full-time researcher and faculty member at a well-respected research university like Texas A&M. “I try to make the most of this opportunity to study and learn in one of the world’s best universities and civil engineering departments,” said Nadkarni. “The faculty and staff are immensely supportive and this university facilitates new ideas and experimentation with thoughts.” 27

Zachry Department of Civil Engineering


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Fall 2016 Graduate Research Magazine  

2016 research magazine showcasing the graduate program and ongoing research in the Zachry Department of Civil Engineering at Texas A&M Unive...

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