SI-29 SOLID-STATE NMR-STUDY OF TRICALCIUM SILICATE AND CEMENT HYDRATION AT HIGH-TEMPERATURE

Si-29 high resolution solid state NMR has been used to follow the hydr ation kinetics of class G Portland cement and of its major component : tricalcium silicate Ca3SiO5 (C3S). Samples were hydrothermally synthe tized at temperatures between 60 and 120-degrees-C; hydration was stop ped at selected reaction times, from 30 minutes to 14 days, by the ace ton-ether method of water-removing. Si-29 NMR spectra of hydrates clea rly show that, in silicate chains, the ratio between the silicon atoms of end groups and those of middle groups depends not only on the time of hydration, but also on the synthesis temperature.