Hydration
Reactions and Mechanical Strength Developments
of Iron-Rich Sulfobelite Eco-cements
- Publication date
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Abstract
Belite calcium sulfoaluminate (BCSA)
cements are low-CO<sub>2</sub> building materials. However, their
hydration behavior and its effect
on mechanical properties have still to be clarified. Here, we report
a full multitechnique study of the hydration behavior up to 120 days
of nonactivated and activated BCSA laboratory-prepared clinkers, with
β- or α<sub>H</sub>-belite as main phase, respectively.
The effects of the amount of gypsum added were also studied. The hydration
and crystallization processes are reported and discussed in detail.
Finally, shrinkage/expansion data are also given. The optimum amount
of gypsum was close to 10 wt %. Our study has demonstrated that β-belite
reacts at a higher pace than α′<sub>H</sub>-belite, irrespective
of the gypsum content. The hydration mechanism of belite determines
the development of the mechanical strengths. These are much higher
for activated BCSA cement, ∼65 MPa at 120 days, against ∼20
MPa for nonactivated BCSA cement, with the latter having larger amounts
of stratlingite
