Simulation of connectivity of capillary porosity in hardening cement-based systems made of blended materials

G. Ye, K. van Breugel
Microlab, Faculty of Civil Engineering and Geosciences, Delft University of Technology, The Netherlands

In recent years, the durability of reinforced or prestressed concrete structures has become a main concern. A key parameter in durability predictions is the microstructure of the surface zone of concrete structures, i.e. the “covercrete”, more in particular the connectivity of the pores in the cement paste matrix. In this paper, the connectivity of capillary pores in hardening cement-based system made of blended materials is studied numerically. The blended materials include blast furnace slag and limestone powder. In the numerical simulation, the hydration of the multi-components, i.e. cement particle and filler particle are considered. The stereological aspect, the interaction mechanism on both cement particle and filler particle, the basic rate equation and the influence factors are modeled. The simulated microstructure parameters, like capillary porosity and connectivity of capillary pores were analyzed based on the percolation theory. The simulation results were discussed and validated against experimental measurements. It is concluded that the connectivity of capillary pores can be manipulated by using different blended materials.

Key words: Blended cement, connectivity, numerical simulation