Mechanical and durability assessment of slag based alkali-activated binders incorporating granite dust

Cement concrete is a popularly used construction material that creates a high emission of carbon footprint. To address contemporary issue nowadays, Alkali Activated Binders (AAB) products’ inclusion of industrial wastes has shown a sustainable and environmentally friendly system with appropriate strength and durability. This study explores the production of alkali-activated binder with GGBS as a source material and replacing river sand with granite dust in varying proportions (0%, 10%, 20%, 30%, 40%, and 50%) with the alkali activation of NaOH & Na₂SiO₃ and KOH & K₂SiO₃ subjected to heat and ambient curing conditions. The mechanical and durability properties of AAB are evaluated in this research paper. The compressive strength results reveal that AAB activated with Na and K solutions with replaced fine aggregate would be optimal at 30% for 3, 7, and 28 days. However, the ambient-cured AAB specimens have a superior compressive strength than the heat-cured AAB. Specifically, the compressive strength of sodium-based AABs was 71.5 MPa and 57.9 MPa for ambient and heat curing at 28 days, respectively, whereas potassium-based AABs showed strengths of 55.4 MPa and 45.33 MPa under the same conditions. Furthermore, water absorption, sorptivity, and exposure to acids of AAB are assessed for 28 and 56 days along with the scanning electron microscopic characterization. Water absorption through capillary pores was reduced to 12% for Na-based activators compared to K-based activators. This trend is consistent with the durability properties, as sodium-based specimens demonstrated superior resistance when exposed to sulfuric and hydrochloric acids. Notably the increasing amount of granite dust decreases water absorption and sorptivity. Irrespective of the activator, mass loss and strength loss are found when the AAB is exposed to sulphuric and hydrochloric acids.