The aim of this work is to clarify the effect of various activation methods on the hydraulic properties of γ-C2S, one
of the main phases in stainless steel slags. Synthetic C2S, sintered at 1450 °C for 20 h, consisted of 88wt.% γ-C2S
and 12wt.% β-C2S. Two activation paths were followed: mechanical activation, by means of high energy milling,
and chemical activation, by means of NaOH and Na2CO3 addition. Results indicated that both mechanically
and chemically activated γ-C2S hydrated at ambient temperature. XRD analysis showed that the amount of
amorphous phase increased during hydration, whereas TGA/DTG data revealedweight loss in the decomposition
region of C–S–H. Analyses by FTIR and SEM also support that C–S–H is one of the main hydration products.
Mortars prepared with mechanically and chemically activated γ-C2S developed mechanical strength, reaching
the values of 9.1MPa and 10.3MPa at 90 days, respectively.