Use of cold-bonded blast furnace slag aggregate in the production of self-compacting concretes

This study addresses an experimental program carried out to investigate the properties of self-compacting concretes (SCCs) in whichnatural coarse aggregates had been substituted by artificial slag aggregates (ASA). For this, a powder mixture of 90% ground granulated blast furnace slag and 10% portland cement by weight were pelletized in a tilted pan through cold-bonded agglomeration process. The hardened ASAwere tested for specific gravity, water absorption, and crushing strength. Thereafter, they were partially used in producing SCCsin which ASA replaced the natural coarse aggregates in the volume fractions of 0%, 20%,40%,60%,80%, and 100%. Therefore, a total of six mixes with a water/binder ratio of 0.32 were designed and cast using both natural and/or ASA coarse aggregates.Fresh properties of SCCs were observed through slump flow time, flow diameter, V-funnel flow time, and L-Box filling height ratio.Hardened properties of SCCs were measured at 28 and 56 days for compressive strength, splitting tensile strength, chloride ion permeability, gas permeability, andsorptivity. Test results indicated that utilizing of ASA enhance the fresh properties of SCCs, alsoreduce the amount of superplasticizerto achieve a constant slump flow diameter. Moreover, SCCs incorporating ASA displayed better performance than the control mixture in terms of compressive strength, chloride ion penetration, gas permeability, and sorptivity,only the splitting tensile strength had slightly decreasing tendency.Keywords: Artificial aggregate,cold bonding process,ground granulated blast furnace slag, self compacting concrete, transport properties.