Youngguk Seo is interested in the characteristics of multi-phased transportation materials such as asphalt concrete and cement concrete mixtures that reveal elastic, plastic, viscoelastic, and viscoplastic behaviors under the combination of mechanical and environmental loadings. Focusing on fracture and fatigue failures, Dr. Seo has developed models to predict them better in the field as well as to supplement pavement design guides and pavement management systems. Since 2004, his research has expanded into full-scale field experiments and led multiple national projects at the Korea Expressway Corporation Test Road (KECTR) - a 7.7 km long highway test road - in South Korea. These field studies laid a foundation for calibration and validation of the mechanistic-empirical pavement design. From 2013 to 2014, as a pavement engineer at Turner Fairbank Highway Research Center (TFHRC) of Federal Highway Administration (FHWA), Dr. Seo conducted a performance ranking study on recycled materials such as Recycled Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS) using Accelerated Loading Facilities (ALF). Dr. Seo's research also covers the design and building of sustainable infrastructure, greenhouse gas (GHG) emission quantification during construction and operation of highways, and snow melting using new and renewable energy sources.