We would like to thank the past and present management of the Building and Fire Research Laboratory at NIST for their support of the computational materials science of concrete over the last 20 years. Without this long-term support, this development would not have happened. We would also like to thank the Center for Advanced Cement-Based Materials for their support of this work over the last 11 years. Many individuals have contributed to these developments, and we cannot take space to name them all. However, some key individuals whose ideas and/or encouragement were crucial at various points include: M.F. Thorpe, H.M. Jennings, J.R. Clifton, D.A. Quenard, L.M. Schwartz, and J.F. Young.