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Three-dimensional computer simulation of portland cement hydration and microstructure development
A three-dimensional computer model for the simulation of portland cement hydration and microstructure development has been developed. Starting with a measured particle-size distribution and a set of scanning electron microscopy images, a three-dimensional representation of a cement of interest is reconstructed, matching the phase volume fractions and surface-area fractions of the two-dimensional images. A set of cellular-automata rules is then applied to the starting microstructure to model the chemical reactions for all of the major phases during the evolving hydration process. The dissolution cycles used in the model have been calibrated to real time using a single set of parameters for two cements at three different water-to-cement ratios. Based on this calibration, there is excellent agreement between the model predictions and experimental measurements for degree of hydration, heat release, and chemical shrinkage. The degree-of-hydration predictions have been successfully applied to predicting the compressive strength development of mortar cubes for the two cements. The effects of temperature have been examined by performing hydration experiments at 15, 25, and 35 deg C and applying a maturity-type relationship to determine a single degree of hydration-equivalent time curve that can be compared to the model predictions. Finally, the computer model has been further extended to simulate hydration under sealed conditions, where self-desiccation limits the achievable hydration. Future efforts will concentrate on the incorperation of mineral admixtures, such as silica fume and fly ash.
Three-dimensional computer simulation of portland cement hydration and microstructure development
A three-dimensional computer model for the simulation of portland cement hydration and microstructure development has been developed. Starting with a measured particle-size distribution and a set of scanning electron microscopy images, a three-dimensional representation of a cement of interest is reconstructed, matching the phase volume fractions and surface-area fractions of the two-dimensional images. A set of cellular-automata rules is then applied to the starting microstructure to model the chemical reactions for all of the major phases during the evolving hydration process. The dissolution cycles used in the model have been calibrated to real time using a single set of parameters for two cements at three different water-to-cement ratios. Based on this calibration, there is excellent agreement between the model predictions and experimental measurements for degree of hydration, heat release, and chemical shrinkage. The degree-of-hydration predictions have been successfully applied to predicting the compressive strength development of mortar cubes for the two cements. The effects of temperature have been examined by performing hydration experiments at 15, 25, and 35 deg C and applying a maturity-type relationship to determine a single degree of hydration-equivalent time curve that can be compared to the model predictions. Finally, the computer model has been further extended to simulate hydration under sealed conditions, where self-desiccation limits the achievable hydration. Future efforts will concentrate on the incorperation of mineral admixtures, such as silica fume and fly ash.
Three-dimensional computer simulation of portland cement hydration and microstructure development
Dreidimensionale Computersimulation der Portlandzement-Hydratation und der Mikrostrukturentwicklung
Bentz, D.P. (Autor:in)
Journal of the American Ceramic Society ; 80 ; 3-21
1997
19 Seiten, 18 Bilder, 9 Tabellen, 67 Quellen
Aufsatz (Zeitschrift)
Englisch
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