Dynamics Of Water Contained In Cement Pastes Studied By Analysis Of Quasi-elastic Neutron Scattering Spectra

China Spallation Neutron Source(CSNS) as a major national science and technology infrastructure will have been built in 2018. CSNS will provide a platform for the study of physics, medicine, bioscience, chemistry and other disciplines multidisciplinary, and high-tech application. Neutron powder diffraction is the most widely used spectrometer,quasi-elastic neutron scattering(QENS) related information can be acquired through the back scattering spectrometer.QENS is a novel experimental technique to study the dynamics of confined water in cement paste. There are bound water and confined water in cement paste. The fraction of these water vary with the curing time of cement paste, the environment temperature, the weight ratio of water and dry cement, and the kind of additive in cement paste. The dynamics of confined water in cement pastes is an important factor which is related to concrete property in durability and mechanism. It is significant to study the dynamics of confined water in cement paste.In our work, the improved empirical diffusion model(EDM) has been used to the nonlinear least square fitting of the QENS experimental data of cement samples cured for7, 14 and 30 days and C-S-H samples with different water contents from 10% to 30%(by weight), where an energy resolution function of four Gaussian terms instead of one Gaussian term is utilized during the fitting process. Parameters of the dynamics of water in cement samples and C-S-H samples have been deduced.Fitted QENS spectra are very well and the dynamics of water in cement samples and C-S-H samples can be quantitatively explained with these deduced parameters. All this provides a practical and useful method for spectral analysis of QENS on dynamics of water in cement.