High strength one-part alkali-activated slag blends designed by particle packing optimization

[Display omitted] •One-part alkali activated binary and ternary mortar blends are designed by optimizing the particle packing.•Distribution modulus to be chosen based on the mix composition for maximum packing density.•A record high strength of 145 MPa is achieved with ternary blend with slag, silica fume and phyllite dust.•Addition of silica fume resulted in cross-linked C-A-S-H and N-A-S-(H) formation. This paper focuses on the development of high-strength and eco-friendly one-part (i.e., dry-mix) alkali-activated mortar with ground granulated blast furnace slag as the main precursor. In addition to slag, phyllite dust and silica fume were used as co-binders in binary and ternary blends to improve mechanical properties. Particle packing optimization was employed for the mix proportioning to achieve a compact matrix skeleton. The results revealed that a 10% increase in mortar strength was gained after adjusting the particle packing and an additional 20% increment was observed after blending the slag with other mineral admixtures. Ternary blend with all three binders achieved a mortar compressive strength value of 145 MPa (at 28 d age), which is the highest strength reported in one-part alkali-activated materials. Additionally, ternary blends present potential economic benefits because of their ability to replace slag with lower-cost industrial side streams.