Dr. Lori Tunstall
The replacement of prematurely deteriorating concrete represents a significant economic and environmental cost each year. One of the best ways we can reduce this impact is to improve the durability of concrete. This talk will focus on my past research in cementitious and pozzolanic materials and my research plan at Georgia Tech. This is a two-fold approach that 1) builds on my existing expertise in frost durability (immediate applications, extension to novel low-CO2 cements), and 2) works to develop novel self-healing bio-cements (low technological readiness, but high-reward). I will also discuss my funding plan and potential cross-collaborative opportunities for advancing 3D-printed concrete, such as incorporating a printed circuit that can assist in structural health monitoring.
Previously, I found that the microstructure of the air void shell plays an essential role in the frost protection of concrete, a feature related to calcium ion interaction with air entraining agents (AEAs). This may explain adverse interactions with other cement additives, since additives that interfere with this calcium interaction are expected to lead to inferior frost protection. I have also developed a new theory to account for air loss in cement systems containing fly ash. Air loss is not due to adsorption onto carbon in the fly ash, but rather adsorption onto the glassy fly ash particles that are caged inside hollow carbon shells and unable to participate in air void formation. My future research plan at Georgia Tech will continue my basic research in the area of durability, with the additional focus of studying the role of Pickering stabilization in air void formation.
My work will also include the development of a self-healing bio-cement using biogenic hydroxyapatite (HAP). One of the most promising advancements in self-healing concrete has come from the incorporation of mineral-producing bacteria to create a biocement which results in the production of calcium carbonate that can heal small cracks. This material advancement would have many useful applications, for instance sewage systems, nuclear waste containment and cement wells for CO2 injection, all of which are harsh environments for which a self-healing failsafe could be particularly beneficial.
Lori E. Tunstall graduated summa cum laude from The College of New Jersey in 2008, earning a B.S. in Civil Engineering and a minor in English. After gaining work experience as a geotechnical engineer and construction estimator, she joined the graduate program at Princeton University, earning a joint Ph.D. in Materials Science and Civil and Environmental Engineering in 2016, studying under Prof. George W. Scherer. Princeton University distinguished Dr. Tunstall with two awards during her graduate program, the Wu Graduate Fellowship in Engineering and Princeton’s Emerging Alumni Scholars Award for 2015 – 2016. She was selected as a part- time resident at Lawrence Livermore National Lab, where she is responsible for technology transfer between the two sites, and received the 2017 Defense Programs Award of Excellence for her contributions in solving a critical manufacturing issue.