Using Wetsuits and Hardhats, CCEE Brings Research into the Field

While one might think of instrument-filled laboratories or computer screens filled with computer code when thinking of university research, faculty and graduate students in the Civil, Construction, and Environmental Engineering Department are often getting their hands dirty in the field. There’s no replacing hands-on field work when research requires measurements of a property or phenomena of interest or to test engineered solutions under real-world conditions. Here we highlight a few recent field-based projects to give an idea of the breadth of work ongoing in the department and the range of settings, questions and partners involved when we’re working ‘in the field.’

Jumping in to Understand Coastal Processes

Dr. Margery Overton conducts research to understand the response of the coast to waves, tides and currents, and the influence human activities have on these ever-evolving systems. The research team uses numerical models in combination with field data to reproduce the hydrodynamics, sediment transport and morphological change of a tidal inlet. Due to the highly dynamic nature of the coastal features and the risks related to shallow water navigation and instrument mooring, field work requires strategic planning of data collection taking into account water and air temperature, tidal levels, wave conditions, bathymetric change, precipitation, presence of harmful aquatic fauna, maritime traffic and touristic activities. For example, graduate student Liliana Velasquez Montoya partook in a field campaign as part of the Hands-On Field Methods Internship at Woods Hole Oceanographic Institution during the summer of 2014.

Doing the dirty work to Improve Health and the Environment

The aptly named “Excrevator” for emptying pit-latrines in developing countries is now in its third year of funding from the Bill and Melinda Gates Foundation. During testing in Durban, South Africa in August 2014, several areas for improvement were identified, including the need to handle the large amounts of trash present in the pits. MS student Tracey Sisco tested several designs for handling trash including shredding mechanisms, shaftless augers, and vacuum assist techniques. Research Associate Tate Rogers (MS ENE 2012) accompanied Excrevator Version 3, incorporating trash handling techniques, to Malawi for field testing in collaboration with Mzuzu University in December 2014. The Malawi tests yielded promising results. Mzuzu University will continue to test and develop Version 3 with the goal of starting a small pit emptying business focused around the Excrevator. NC State will continue to develop and implement new designs for field testing in 2015. Rogers and Dr. Francis de los Reyes will attend the January 2015 Fecal Sludge Management Conference in Hanoi, Vietnam to present their latest results.

Research associate Tate Rogers (MS ENE 2012), and Mzuzu University MS students testing the latest version of the Excrevator on a pit latrine in Mzuzu, Malawi.

Defusing an Explosive Situation

Firing ranges for grenades and mortars used by the US Department of Defense (DoD) for personnel training have been contaminated with explosive residues such as TNT that can leach into ground water. These residues include possible human carcinogens. A major challenge in managing explosive residues is the presence of unexploded ordinance (UXO). UXO greatly increases costs and worker exposure associated with site remediation. Under the supervision of Dr. Robert Borden, graduate studentsJongho Won, Stewart Farling (MSENE 2013), and Della Shaw (MENE 2014) are evaluating a new approach developed in CCEE, and being tested at Ft Bragg, NC, with funding from the US Department of Defense (DoD). The approach involves spraying a mixture of water, lignin and glycerol on firing ranges requiring treatment. Once applied, the lignin and glycerol are intended to enhance biodegradation of TNT in a process similar to that commonly used in wastewater treatment plants. The glycerol and lignin solution can be spray applied from over 100 ft, greatly reducing costs and potential worker exposure to UXO.

In March 2013, the students worked with field crews from Solutions-IES, Inc. to install monitoring and sampling equipment below-ground in trenches within two hand grenade throwing bays. Jongho and Della collected soil samples from the bay for the initial site characterization while the instrumentation was installed. In July 2013, the water, lignin and glycerol mixture was sprayed on the surface of one bay while a second was used as a control. The students are monitoring soil pore water for explosives concentrations and indicators of degradation of the explosives. Initial results indicate that treatment is effective; however, monitoring is ongoing. Once final results are in, DoD will consider whether this treatment should be applied at other military bases globally.

PhD student Jongho Won (on right), Della Shaw (MENE, 2014) (middle), and field crews from Solutions-IES, Inc. assemble monitoring and water sampling equipment at Fort Bragg, NC (March 2013).

Hitting the road: providing economical highway designs

Drs. Roy Borden and Mo Gabr are leading research to improve the design of temporary slopes and excavations in soils in North Carolina’s Piedmont region. Natural steep slopes are often found to be stable even if they are not predicted to be safe using conventional analysis techniques. Suction from capillary action in partly saturated soil, referred to as “matric suction,” may be an overlooked factor that may help stabilize some naturally steep slopes. Graduate students Cheng Wang (PhD 2014),Jungmok Lee, Chien-Ting Tang, and Justin Pescosolido have been monitoring matric suction within soil at a NC Department of Transportation construction site in Greensboro, NC. Field monitoring, combined with laboratory experiments, will lead to improved understanding of unsaturated soil behavior in the Piedmont. Improved understanding of soil behavior will enable improve designs of temporary slopes and excavation support systems, leading to steeper, and more economical, temporary slopes.

Cheng Wang (PhD, 2014) measuring the matric suction of the soil in the field using a tensiometer.

The use of pavement surface treatments (PSTs) is growing as a technique for maintaining acceptable road performance under tight budgetary constraints. A PST consists of a thin protective layer of asphalt to seal an existing pavement surface. Ongoing research conducted under the direction of Drs. Richard Kim and Cassie Castorena include both National Cooperative Highway Research Program (NCHRP) and North Carolina Department of Transportation (NCDOT) funded projects which seek to improve the overall quality and maximize the performance benefits of PSTs. Research efforts include the development of performance-related specifications for chip seal mixtures (funded by NCDOT) and binders (funded by NCHRP). As part of these projects, field sections were constructed and monitored for performance by graduate students Javon Adams and Mohammad Illias. NCDOT-funded research conducted by Dr. Kim and graduate students Adams and Mehdi Mashayekhi has included development of field tests to improve quality control. In addition, a test has been developed by Dr. Castorena and graduate student Mary Rawls for in-situ measurement of emulsion application rates. The rate of emulsion application is critical in determining pavement performance.

CCEE graduate students Mary Rawls and Javon Adams conducting tack lifter field trials at a rural North Carolina field site.

The Road to Cleaner Air

For 15 years, Dr. H. Christopher Frey, collaborators including Drs. Nagui Rouphail and William Rasdorf, and students (both graduate and undergraduate) have conducted field measurements of the real-world activity, energy use, and exhaust emissions of over 200 vehicles, including cars, trucks, construction equipment, snow vehicles, and railroad locomotives. Unlike laboratory measurements, in-use measurements more accurately represent when and where emissions occur and how they can be reduced. Methods for study design, data collection, quality assurance, and data analysis developed at NC State have influenced researchers and practitioners globally. In addition to extensive local data collection, NC State vehicle emissions research teams have been dispatched to Georgia, Florida, New Jersey, New York, Wyoming and internationally to Canada and England.

Portable Emission Measurement System (PEMS) for measuring tailpipe exhaust emissions and a laptop computer for recording engine data installed inside a passenger car.