Microstructural Modelling of Self-Desiccation During Hydration.
Microstructural Modelling of Self-Desiccation During
Bentz, D. P.; Snyder, K. A.; Stutzman, P. E.
Self-Desiccation and Its Importance in Concrete
Technology. Proceedings. International Research
Seminar. June 10, 1997, Lund, Sweden, 132-140 pp, 1997.
cement hydration; building technology; capillary
porosity; computer models; curing; microstructure;
A three-dimensiond cellular automation-based
microstructural model has been applied to simulate the
process of self-desiccation during the hydration of
cement paste. As hydration occurs, the proper amount of
empty pore space, corresponding to the chemical
shrinkage of the cement paste, is created within the
microstructure. This empty pore space in turn influences
the future kinetics of the hydration process, as less
water-filled space is available for the dissolution and
precipitation of cement phases. Model predictions are
compared with experimental data, including both SEM
images of microstructure and measurements of degree of
hydration based on non-evaporable water content. For
water-to-cement ratios below 0.40, sealed curing
conditions are seen to result in a significant decrease
in the achievable hydration, relative to curing under
saturated conditions. The addition of silica fume is
observed to further increase the self-desiccation and
decrease the achievable degree of hydration. The model
can also be adapted to other curing scenarios, such as
saturated curing until the capillary porosity becomes
disconnected, followed by sealed curing, to assess the
effects of different curing regimens on the hydration
and subsequent performance of cement-based materials.