The Microstructure Study On Calcium-Silicate-Hydrate (C-S-H) By X-ray Scattering

The main product of the reaction of dry portland cement with water is the calcium silicatehydrate （C-S-H）, which accounts for over60percent of composition in the portland cementclinker. To product one ton of Portland cement clinker, approximately0.8tons of CO₂is emittedinto the air, which contributes5%-7%of the total man-made CO₂emissions. In order toreduce CO₂emissions, it is necessary to study the microscopic structure of the C-S-H in Portlandcement.In this thesis, we analyzed the small angle X-ray scattering experimental data of thePortland cement paste, combining with the atomic structure of C-S-H model proposed by otherscholars, the information about the microstructure of the C-S-H was provided.Firstly, the scattering structure factor could be calculated by the X-ray scattering intensitydata and was fitted by the nonlinear curve fitting, in order to determine the spacing of the thecalcium silicon layer in the C-S-H. Next，based on the scattering structure factor above, thereduced pair distribution function was obtained by Fourier transformation. By Gaussian fittingof the reduced distribution function obtained above, the distance of each atom pair in the C-S-Hwas obtained. Finally, according to the results about the distance of each atoms in the C-S-H ofevery Portland paste sample, the results could be found that the additive and the aging time had alittle influence on the distance of each atoms in the C-S-H.During all the data analysis, massive analyses were taken by the pair distribution functionanalysis （PDF） method, and the results were credible. All of these could provide a reference forthose who interested in studying on the microstructure analysis.