Lori Tunstall (née Ruggiero)

    I am a second-year PhD candidate in the department of Civil and Environmental Engineering. I am working in collaboration with NIST, Massachusetts Institute of Technology, and University of California, Berkeley, to develop a working model of cement paste that incorporates fly ash.

    With one ton of cement releasing about 0.34 tons of carbon dioxide into the atmosphere, cement is a significant contributor to greenhouse gas emissions. It is also the most expensive component of concrete. Alternatively, fly ash is a relatively cheap byproduct that can partially replace cement with many favorable improvements to concrete such as workability, strength, and lower heat of hydration. Although fly ash concrete mixes have economic, environmental, and performance benefits, the fly ash is variable and thus its performance is unpredictable, especially in regards to frost resistance.

    Some sources suggest that inadequate frost resistance in these mixes is due to the carbon contamination in fly ash, which interferes with the efficacy of air entrainment agents (AEAs). Recently, I have been examining this claim through adsorption tests using thermogravimetric analysis and nuclear magnetic resonance for different combinations of four chemically diverse AEAs and three types of fly ash. Once I confirm which fly ash/AEA combinations show adsorption behavior, dynamic mechanical analysis will be used to evaluate the freezing behavior of mortar mixes of each fly ash/AEA combination to determine if there is any correlation between adsorption and freezing behavior.

    My research is supported by ARRA Stimulus Funding through NIST. I am very grateful for the opportunity to study and research among such brilliant scholars and I hope to repay my gratitude someday by contributing to the academic and scientific community in some significant way!

My Photo Albums

In a course-related poster session at Princeton, I presented a poster entitled, Impact of Impurities in Fly Ash on the Durability of Concrete, describing the preliminary steps of my research.

My Publications