Effect of Ground Granulated Blast Furnace Slag Particle Size Distribution on Paste Rheology: A Preliminary Model

Ground granulated blast furnace slag is widely combined with Portland cement as a supplementary material, and is also used in alkali-activated binders (geopolymers) and in supersulfated cements, which are potential replacements for Portland cement with significantly reduced carbon dioxide emissions. The rheology of a cementitious material is important in terms of its influence on workability, especially in self leveling concretes. The current research investigates the effects of different particle size distributions of slag particles on paste rheology. Rheological measurements results show a direct relationship between the modal particle size and the yield stress of the paste. An empirical model is introduced to calculate the yield stress value of each paste based on the particle size distribution, and applied to a range of systems at single water to solids ratio. The model gives a very good match with the experimental data.