Effect of the synthesis temperature on the hydration reaction of Fly Ash Belite Cement

Fly Ash-Belite Cement (FABC) is being synthesised in our laboratory by means of a low-energy method which is based on a previous hydrothermal activation of the fly ash pozzolanic reactivity in the presence of lime and water. In the present paper the effect of the synthesis temperature on the hydration reaction of the FABC is presented. The temperatures studied after hydrothermal treatment were 700 degrees C, 800 degrees C and 900 degrees C. Pastes were prepared with FABC (fabricated with two kind of Spanish fly ashes (ASTM Class F) of different granulometry), at a demineralized water to cement ratio of 0.75. The pastes were kept at >90% rh and 21 degrees C+/-2 degrees C during a period of 200 days from mixing. The evolution of the hydration reaction was followed by the combined water content which was evaluated from thermogravimetry (TG) analysis, X-ray diffraction (XRD) and infrared spectroscopy were used to the characterisation of the solid phase.