A neutron scattering study of the role of diffusion in the hydration of tricalcium silicate

Quasi-elastic neutron scattering was used to monitor the temperature-dependant hydration of tricalcium silicate and Portland cement. Results show that for some samples the degree of hydration is in fact higher at lower curing temperatures. To investigate this effect further, we performed a series of experiments in which samples are initially hydrated at one temperature and then the diffusion process limiting the long-term curing is monitored at a different temperature. The results confirm that the higher the initial curing temperature the more impervious are the product layers to later diffusion. In addition, it was found that the intrinsic activation energy for this diffusion process is much greater than the traditional values obtained using samples initially cured at different temperatures. D 2002 Elsevier Science Ltd. All rights reserved.