Producing of alkali-activated artificial aggregates by pelletization of fly ash, slag, and seashell powder

Abstract

In the construction sector, the material supply chain of aggregates is frequently disturbed due to seasonal unavailability, quarrying issues, and environmental norms. The production of artificial aggregates has gained prominence to conserve natural resources and promote green construction practices. The current study encompasses the production of alkali-activated artificial aggregates through cold-bonding pelletization technique using three different raw materials, including fly ash, ground granulated blast furnace slag, and seashell powder in binary and ternary blending combinations. The cold bonding was achieved by alkali activation of binders with the aid of a sodium-based alkaline solution, which acts as an activator and hydrating liquid. The fresh artificial aggregates were subjected to surface treatment using the same alkaline solution to enhance their characteristics. The mechanical properties of artificial aggregates confirmed their potential as a substitute for conventional aggregates by exhibiting crushing and impact values of 18.19–27.53% and 12.06–18.85%, respectively. The microstructural and mineralogical characteristics depicted dense microstructure and compact matrix. The study concludes that artificial aggregates can effectively replace natural coarse aggregate in making structural concrete with many economic, environmental, and technical advantages.