Combined Use of Natural and Artificial Slag Aggregates in Producing Self-Consolidating Concrete

This study addresses properties of self-consolidating concrete (SCC), in which natural coarse aggregates had been substituted by artificial slag aggregates (ASAs). For this, 90% ground-granulated blast-furnace slag and 10% portland cement by weight were pelletized in a tilted pan through cold-bonded agglomeration process. Then, the hardened coarse aggregates (ASA) were tested for specific gravity, water absorption, and crushing strength. Thereafter, they were partially used in producing SCCs in which ASA replaced the natural coarse aggregates at 0, 20, 40, 60, 80, and 100% by volume. Therefore, six SCCs with 0.32 water-binder ratio (w/b) were designed and cast using both natural and/or ASA. Hardened concrete properties were tested for compressive and splitting tensile strengths, modulus of elasticity, drying shrinkage, freezing-and-thawing resistance, chloride ion permeability, gas permeability, and sorptivity. Test results indicated that SCCs with ASA displayed better performance than the control mixture in terms of durability-related properties. Incorporating ASA in SCCs increased the compressive strength and elastic modulus (up to 60%) but decreased the splitting tensile strength. However, ASA provided gradual reduction in sorptivity coefficient, chloride ion, and gas permeability especially at 60% replacement level and 56 days.