Student Spotlight: Rekea' Williams

During the summer of 2019, Rekea' Williams, an undergraduate junior in the Coastal Environmental Science, or CES, program participated in a valuable internship with the U.S. Army Corps of Engineers’ Engineer Research and Development Center, or ERDC, in Vicksburg, Mississippi. There, she performed cutting-edge research and ultimately co-authored a peer reviewed journal publication based on the results. “Impact of Aggregate Mineralogy and Exposure Solution on Alkali-silica Reaction Product Composition and Structure Within Accelerated Test Conditions” was published in the journal Construction and Building Materials in April.

According to Vince Wilson, the CES undergraduate program director, “It’s wonderful to see our undergraduates get published, especially so early in their college careers. Rekea' is a shining example of the quality of students we have here at CC&E who can apply their classroom knowledge to applicable work experiences. That’s the ultimate goal of our CES program.” 

As a freshman, Williams worked in the LSU College of the Coast & Environment’s Sediment Dynamics Lab alongside Kevin Xu, the interim director of the Coastal Studies Institute and associate professor in the Department of Oceanography & Coastal Sciences, and his PhD student, Kelli Moran. There, she prepared and analyzed sediment samples associated with a Coastal Protection and Restoration Authority project investigating how Louisiana’s coasts are shifting over time. These samples were part of a larger project aimed at helping Louisiana weather the future sea level crisis.This experience taught her valuable skills that she was able to apply to her ERDC internship.

At ERDC, Williams worked in the Geotechnical and Structures Laboratory, under the direction of Research and Development Engineer Eftihia Barnes. Williams was part of a team researching damage to concrete structures caused by alkali-silica reaction, or ASR, a chemical reaction between silica-rich aggregates (larger particles in concrete) and alkaline cement paste (smaller particles in concrete) that forms alkali silicate gel. Over time, the gel expands and acts like a wedge, causing concrete to crack. For their research, the team used accelerated aging tests to mimic conditions conducive to ASR gel formation in order to evaluate the resulting damage to different types of concrete. Knowing how ASR gels form and grow, can help develop mitigating strategies than can be used to expand the safety and service life of concrete structures, such as airfields, pavements, and bridges.

Williams assisted in the data collection and analysis by using a Raman Spectroscopy Imaging Microscope to analyze several different mixtures of concrete including Pyrex, Las Placitas, Spratt, and Opal aggregates. According to Dr. Barnes, “This was a challenging task because [Rekea] had to search the surface of each sample using an optical microscope and match the location of previous measurements.”

Ultimately, they found that the structure and composition of ASR gels depends not only on the chemistry of the alkaline solutions they were exposed to, but also on their local environment and the type of aggregate used to make the concrete.

“My summer working at ERDC was awesome because not only was I in a top notch laboratory setting, but I was also able to gain knowledge about the operations of an Army [Department of Defense] facility without being enlisted in service. The type of educational experience I had is rare, and gaining undergraduate research and a published article out of my work makes the experience even more special,” Williams said.

After graduation, Williams plans to continue her education and expand her knowledge to include global coastal environments.

 

*Updated 8/20/2020: A previous version of this article incorrectly attributed Rekea's CPRA work to her time at ERDC. It actually occurred during her time in the Sediment Dynamics Lab. 

 

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