Segmented fractal pore structure covering nano- and micro-ranges in cementing composites produced with GGBS

Abstract

Ground granulated blast-furnace slag (GGBS) is a massively produced waste in iron-making process. In present work, the pore size range of GGBS blended cementing composites is finely segmented to reveal the scale-dependent fractal nature of pore surface. Results indicate that structural complexity and irregularity of C-S-H gels can be improved by GGBS. It is proved that an increase in the pore surface area helps to improve the complexity (fractal dimension, Ds) of the pore wall. Linear growth of Ds with specific surface area exists in almost all pore ranges, especially in mesopore ranges. Fractal dimension in gel pore range shows the highest value, while the value in pore range of 1–10 μm is almost the lowest. The macro region above 1 μm, which is an aggregation of hydrated packing grains, shows a permanent-existing fractal behavior. The capillary pores between 10 nm and 1 μm exhibits drifting non-fractal behavior, from micron-scale to nano-scale with curing time.