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Determination of the Neutron Scattering Contrast of Hydrated Portland Cement Paste Using H20/D20

Published

Author(s)

J Thomas, Hamlin M. Jennings, Andrew J. Allen

Abstract

Accurate measurements of the surface area of cement based materials using small-angle neutron scattering (SANS) require determination of the neutron scattering contrast between the C-S-H gel and H6d2^O. Because the C-S-H gel has a poorly understood structure and a variable composition, calculated values of the C-S-H:H2O neutron scattering contrast based on an assumed C-S-H chemical compostion and density are subject to error. The C-S-H:H2O neutron scattering contrast was determined experimentally by measuring the change in apparent surface area as the H2O in a hydrated cement specimen was replaced with D2O, resulting in a new value of 6.78 X 1028 m-4. This new contrast value increases some previously reported SANS surface area values by 21%. The results also confirm that C-S-H interlayer water should be included in the solid phase whereas gel pore water should be excluded.
Citation
Advanced Cement Based Materials

Keywords

C-S-H, Cement, SANS, Surface area

Citation

Thomas, J. , Jennings, H. and Allen, A. (1998), Determination of the Neutron Scattering Contrast of Hydrated Portland Cement Paste Using H<sub>2</sub>0/D<sub>2</sub>0, Advanced Cement Based Materials (Accessed February 22, 2024)
Created May 31, 1998, Updated October 12, 2021