α-C2SH synthesis in the mixtures with CaO/SiO2 = 1.5 and application as a precursor for binder material

Abstract

The hydration and strength properties of the binder material created on α-C2SH basis were determined. The binder material was prepared by mixing α-C2SH (C/S = 1.5; 16 h, 200 oC) and quartz sand (1:1 by mass) in a homogeniser for 30 min. Later on, sample was ground in a vibrating cup mill at 950 rpm for 4 min and burned at 450 oC for 30 min under air atmosphere. It was determined that calorimetric curve of created binder material differs from the one of ordinary cements as it involves only the three exothermic reactions and the amount of total cumulative heat grows with the increasing hydration time. As expected, the tendency of strength increment was observed after 7-28 days of hardening: compressive strength increased to 15.5 and 24.0 MPa, respectively. The products of synthesis and hardening were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and simultaneous thermal analysis (STA).