Determination of the Neutron Scattering Contrast of Hydrated Portland Cement Paste Using H20/D20
J Thomas, Hamlin M. Jennings, Andrew J. Allen
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.
, Jennings, H.
and Allen, A.
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 May 28, 2023)