Optimization of Particle Packing Density of Industrial Wastes Incorporated Concrete

Growing urbanization and industrialization increase the demand for concrete. A massive amount of natural stone is extracted to meet this demand, rapidly depleting natural resources. One of the steelmaking byproducts, electric arc furnace (EAF) steel slag, could be a sustainable substitute for natural stone. This study aimed to replace natural stone 100% with EAF slag. The concrete was proportioned according to the Modified Andreasen model to ensure the optimal gradation of the particles. Moreover, a wet particle packing density optimization was performed to identify the optimum water content at which the packing density maximizes. Two more industrial wastes/byproducts, viz., fly ash and silica fume, were utilized as supplemental cementitious materials to substitute a portion of cement to investigate their influence on particle packing density and concrete properties. The replacement levels for fly ash were 15 and 30%, while for silica fume, they were 5 and 10%. The workability, strength, water absorption, voids and density tests of the produced concrete revealed that using EAF slag as a coarse aggregate gives promising concrete characteristics. The incorporation of fly ash and silica fume as partial cement substitutes increased the particle packing density of the concrete mixture. However, the silica-fume-based concrete showed better strength characteristics, while the fly-ash-based concrete gave lower reactivity at 28 days.