The present study examined the effect of the activation properties of granulated blast furnace slag
according to the type of alkaline activator, the specific surface area of blast furnace slag, and the amount of
ordinary Portland cement substituted on the compressive strength of the cement containing blast furnace
slag. For activators, Na2SiO3, Na2CO3, NaOH, and Na2SO4 were used. Na2SiO3, Na2CO3, and Na2SO4 were
converted into Na2O, to which 1 wt.%, 3 wt.%, 5 wt.%, and 7 wt.% were added, and subjected to
experimentation, with the W/S (water/solid) ratio = 0.5. The principal hydration products were C-S-H,
C4AH13, Aft (ettringite), and Al(OH)3. Na2CO3 exhibited the largest slag hydration rate. Consequently,
the present study used Na2CO3 as the alkaline activator. The compressive strength of blast furnace slag
cement mortar was then measured according to the amount of Na2CO3 added (2.5 wt.% and 5.0 wt.%), the
specific surface area of blast furnace slag (4,000 cm2/g, 6,000 cm2/g, and 8,000 cm2/g), and the substitution
rate (30 wt.%, 50 wt.%, and 70 wt.%) of the blast furnace slag in terms of ordinary Portland cement. The
results are as follows: at the ages of 1 day and 3 days, respectively, the early strength increased as the
specific surface area of blast furnace slag and the amount of alkaline activator added increased; at the age of
7 or more days, the compressive strength increased as the amount of alkaline activator added decreased and
as the specific surface area of blast furnace slag increased.
INFLUENCE OF SPECIFIC SURFACE AREA AND CALCIUM SULFATE OF BLAST-FURNACE SLAG ON ADDITION EFFECT OF CALCIUM HYDROXIDE POWDER TO THE CEMENT CONTAINING BLAST FURNACE SLAG