Activation of slag: a comparative study of cement lime, calcium sulfate, GGBS fineness and temperature

摘要

In the precast industry very early age strength development is crucial for productivity, and it is for this reason that industry has been reluctant to embrace the use of ground granulated blast-furnace slag (GGBS) as a supplementary cementitious material, despite its lower carbon dioxide (CO2) emissions. This paper explores the replacement of different base cements (CEM II A-L and CEM I (42.5 R)) with slags of different fineness in mixes containing a novel accelerating admixture at different curing temperatures (20, 35, 45 and 55 degrees C for 16 h); results are also compared with cement-slag mortars containing lime (Ca(OH)(2); 6%) and calcium sulfate (CaSO4; 3%) for activating the early age strength. These studies are conducted for a 30% replacement of cement with slag, to establish the benefits offered for very early age strength attainment in the precast concrete industry.