Inelastic neutron scattering study of the hydration of tricalcium silicate

Inelastic neutron scattering is applied for the first time to monitor direc tly the concentration of calcium hydroxide formed during the hydration of t ricalcium silicate. Results taken between 10 and 40 degrees C show that the onset of calcium hydroxide formation is delayed at lower temperatures but that the final quantity formed appears to be converging to a temperature-in dependent value. At 20 degrees C, the 28 day value is 1.3 moles per mole of tricalcium silicate. Combining these results with previous measurements of the free water index made using quasielastic neutron scattering reveals th at the hydrogen content of the C-S-H gel decreases significantly at increas ed curing temperature.