Hamlin Jennings is Professor of Civil Engineering and Chair of the Department of Civil and Environmental Engineering. He has been with Northwestern since 1987. His research is presently focused on determining the structure of C-S-H and how it is influenced by chemistry and applied load, and to finally resolve the mechanisms of its formation (a question first posed by Le Chatelier over 100 years ago). Sensitive neutron scattering techniques are providing new information that along with completing thermodynamic data and constructing the phase diagram is providing a more complete understanding of the how the microstructure of cement-based materials develops. The microstructures of these and other materials are analyzed using an image analysis program that was developed over the last ten years to determine the principle deformations throughout the microstructure at the scale of a pixel due to forces such a drying and external load. A materials science approach is used to establish a basis for designing improved cement based materials.