This document describes the efforts to date for incorporating fly ash and silica fume into the NIST 3-D Portland cement hydration and microstructure development model [1]. A series of fly ashes (from the U.S. and France) have been imaged using a combination of SEM backscattered electron and X-ray signals to distinguish the major phases present (silica, an aluminosilicate, calcium chloride, tricalcium aluminate, a calcium aluminosilicate, anhydrite, and inert material). Computational programs for distributing the cement and fly ash phases amongst a size distribution of three-dimensional particles have been developed. The fly ash components may be distributed randomly amongst a subset of the particles, or as individual monophase particles. Reactions have been established for these starting materials and the phases of ordinary Portland cement based on information available in the literature [2,3]. Volume stoichiometries and heats of reaction have been postulated for these reactions, which then have been included in a new version of the NIST 3-D microstructural model. Some validation against adiabatic heat release curves has been performed for one of the French fly ashes. The basic procedures are thus in place for modelling the hydration behavior of a variety of blended cements (and concretes), but further validation and adjustment of some constants (reactions rates, etc.) is still needed. A suggested approach for performing this validation is also presented.
The new version of the hydration model and the auxiliary programs provided in Appendix B are available via anonymous ftp from ftp.nist.gov (129.6.13.25). The user can log in as ``anonymous'' and supply their e-mail address as the password. The new programs can be found in the /ftp/pub/bfrl/bentz/CEMHYD3D/flyash subdirectory. The programs have been developed and executed on a UNIX-based computer system and should require no more than 16 Mbytes of memory for execution. In addition, a postscript version of this documentation can be found in the /ftp/pub/bfrl/bentz/CEMHYD3D/flyash/manual subdirectory. Complete documentation for the 3-D cement hydration and microstructure development program has been published previously [1] (also available in the /ftp/pub/bfrl/bentz/CEMHYD3D/manual subdirectory) and should be consulted along with this update.