Investigation of relations between porosity, pore structure, and C1 − diffusion of fly ash and blended cement pastes

Abstract

By-product fly ash from coal combustion influences the properties of cement pastes significantly. A study has been carried out to contribute to understanding the behavior and function of fly ash and other substituents in cement pastes. Comparisons are made with the properties of pastes of as-received portland cement and preliminary comparisons made with granulated blast furnace slag cement and silica fume-cement. Relations between the median pore size, porosity and Cl − diffusion of fly ash-cement pastes, and the implications of observations for diffusion mechanisms and the probable pore structure of the blended cement pastes are discussed. Measurements include non-evaporable water (Wn), porosity and pore structure by mercury porosimetry, Cl − transport by a rapid method under the influence of an applied electric field, and the permeability to water. X-ray diffraction phase characterization has been made before and after Cl − diffusion.