Reference: D.P. Bentz, National Institute of Standards and Technology Interagency Report, Technology Administration, U.S. Department of Commerce, NISTIR 7232, June 2005
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This user's manual provides updated documentation and computer program listings for version 3.0 of the three-dimensional cement hydration and microstructure development model (CEMHYD3D) developed at the National Institute of Standards and Technology. Version 2.0 of CEMHYD3D was released in 2000 and since that time, numerous enhancements and improvements have been made to the programs. The online database of available cements has nearly doubled in size from 14 different cements to 27. Two significant updates have been made to the codes used to create starting three-dimensional microstructures: 1) the incorporation of particles of slag, inert fillers, calcium carbonate, etc. into the particle placement program and 2) streamlining of the chemical phase distribution process. Formerly, the user needed to execute three different programs, three times each to distribute the appropriate volumes (and surface areas) of the four major cement clinker phases throughout the cement particles in the initial microstructure. In version 3.0, these three programs have been combined into a single program and all ancillary calculations have been incorporated into the code so that minimal effort is required of the user. Most of the improvements and enhancements to CEMHYD3D for version 3.0 have been made in the programs simulating the hydration and microstructure development. These include: addition of the influences of limestone (and inert fillers) on hydration, incorporation of preliminary reactions for slags, prediction of the concentration of the pore solution during hydration and its concurrent influence on hydration rates, the ability to execute hydration under sealed/saturated conditions by specifying a number of cycles after which resaturation of the (empty) capillary porosity occurs, the ability to precipitate the C-S-H gel in either a random or a "plate" morphology, and the addition of a one-pixel dissolution bias that allows for the acceleration/retardation of the hydration rates of the smallest cement particles in the three-dimensional microstructure. Several example applications utilizing version 3.0 of CEMHYD3D are presented. Complete program listings are provided in the appendices. This manual and all of the computer programs it describes are freely available for downloading via anonymous ftp from NIST (ftp.nist.gov).
Keywords: Building technology; cement hydration; computer modeling; microstructure; simulation.
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