Effect of particle size distribution on microstructure and chloride permeability of blended cement with supplementary cementitious materials

Abstract

In order to improve the chloride ion penetration resistance of supplementary cementitious materials (SCMs) in blended cement, this study optimizes the particle size distribution of cementitious components based on the Fuller model. Portland cement (PC), fly ash (FA), and ground granulated blast furnace slag (GGBFS) are successfully divided into four particle size ranges by precision air classifier, which are 0–8, 8–30, 30–50, and 50–80 μm, respectively. The optimum cementitious materials in four ranges based on 28-day compressive strength are determined by nine groups of orthogonal tests. The blended cement with optimal performance is obtained by GGBFS in 0–8 μm, PC in 8–30 μm, GGBFS in 30–50 μm, and FA in 50–80 μm. The results show that the blended cement with SCMs based on Fuller model have superior microstructure and chloride ion penetration resistance, which is due to their smaller pore size, a strong volcanic ash effect, and chloride ion binding ability. In addition, this research presents a novel approach for realizing the application of a large amount of SCMs in blended cement.

Keywords

• supplementary cementitious materials
• particle size distribution
• chloride diffusion coefficient