Solid Phases Percolation and Capillary Pores Depercolation in Hydrating Cement Pastes

Abstract

Solid phases percolation and capillary pores depercolation in hydrating cement pastes show great influences on mechanical properties and durability. In this paper, two nondestructive apparatuses, ultrasonic wave measurement and noncontacting electrical resistivity device, were used to in situ continuously track solid phases percolation and capillary pores depercolation evolution in cement pastes, respectively. In parallel with experiments, a hydration model was employed to simulate the early age formation of microstructure. The results show that first percolation (first depercolation) time and fully percolation (fully depercolation) time for solid phases (capillary pores) are identified from velocity (resistivity) curves. On one hand, a correlation is found between the change in connected volume of solid phases simulated with model and the evolution of velocity tested by ultrasonic wave measurement. In contrast, the development of resistivity is a good indicator for evaluating the depercolation of capillary pores.