My teaching and research focuses on materials used in civil engineering applications. I primarily examine chemical issues in cement-based materials including phase formation in cement clinkering, hydration of portland cement and related systems, and chemical deterioration processes in concrete.
My current research efforts emphasize the interaction of cement-based materials and the environment. This work encompasses the development and characterization of cementitious systems with lower carbon dioxide and energy footprints, as well as the capacity of cementitious materials to produce or remove airborne pollutants. For example, in my laboratory we have designed and tested a calcium sulfoaluminate-belite cement, made from a combination of natural and waste materials, that has similar compressive strength and volume stability to portland cement, but with a lower lime content and burning temperature. We also have a considerable effort underway enhancing the performance of natural supplementary cementitious materials (SCMs) such as calcined clays, zeolites, and pumices to encourage their adoption as partial replacements of portland cement in concrete. Our work on fly ash SCMs is breaking new ground by quantitatively characterizing the compositions of the complex glasses in these waste materials, then linking these compositions to performance in both cement-based materials and geopolymers made from alkali-activated fly ash. Through collaborations with environmental engineers, we are investigating radon emissions from concrete and its constituents, enabling the design of concrete mixtures with the least potential to expose building occupants to hazardous levels of radon. On the other hand, we are also exploring the passive removal of pollutants such as nitrogen oxides and ozone by cement-based renders and photocatalytic stuccos and paints, spanning both laboratory and field work.