Two-step precipitation preparation and self-setting properties of tricalcium silicate

Tricalcium silicate (Ca3SiO5) powders were synthesized by a novel precipitation method with Ca(NO3)2·4H2O, Na2SiO3·9H2O and Na2CO3 as the starting materials. Pure Ca3SiO5 was obtained at 1400 °C for 8 h. The characteristics of tricalcium silicate powders prepared by this method were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and laser particle size analyzer, and compared with the powders prepared by the sol–gel method reported in a previous study. The effects of the size of the powder on the self-setting properties of Ca3SiO5 were also investigated. The result showed that the size of Ca3SiO5 powders prepared by the two-step precipitation method was 1–10 μm and less than that of Ca3SiO5 powders prepared by sol–gel method. The results showed that the reduction of the particle size accelerated the setting and hardening of the cement and resulted in a significant increase of the compressive strength of the cement.