Caleb Lunsford ’23


Civil and Environmental Engineering

Project Title

Composition and Properties of Alkali-activated Metakaolin

Presentation Link

View Caleb's Presentation

Certificate(s): Architecture and Engineering

Currently, the production and use of concrete and cement accounts for 8% of yearly global carbon emissions. My internship studied alkali-activated metakaolin (AAMK), a potential replacement for traditional ordinary portland cement (OPC). The physical properties and emissions of a batch of AAMK depend greatly on the mix of chemicals used to make the alkaline solution that activates the metakaolin clay. I compiled previous research data and analyzed the AAMK cement mixes that were tested. By comparing the recorded compressive strength with known carbon emissions, I was able to identify potential cements that would have similar or better performance than OPC. With this information, I selected three potential alkali solutions and created cylindrical samples for testing in the lab. While all samples produced less emissions than an OPC sample, the AAMK cement paste was much stickier. This made it difficult to remove all of the air bubbles before the cylinders fully set. These air voids acted as flaws, reducing the compressive strength of the cement below the preferred level. Further tests and adjustments need to be performed to adjust the AAMK cement mixes to remove all air voids before they will be suitable for use.

Internship Year


Project Category

Innovation and a New Energy Future


Sustainable Cements Group, Department of Civil and Environmental Engineering and the Andlinger Center for Energy and the Environment, Princeton University - Princeton, New Jersey


Claire White, Associate Professor of Civil and Environmental Engineering and the Andlinger Center for Energy and the Environment