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 deg. 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