Measurement of Proton Spin Diffusivity in Hydrated Cementitious Solids

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nuclear Magnetic Resonance Spectroscopy

Background:

• Studying hydration and crystallization of inorganic oxides is challenging due to disorder and heterogeneity.
• Solid-state nuclear magnetic resonance (NMR) with proton-proton (¹H-¹H) spin diffusion aids in characterizing spatial composition and domain structures in solids.
• Existing ¹H-¹H spin diffusion analyses require measurements on separate, closely related systems.

Purpose of the Study:

• To develop and apply an experimental NMR method for determining proton spin diffusion coefficients in hydrated cementitious materials.
• To overcome limitations of previous methods in analyzing disordered and heterogeneous solid systems.

Main Methods:

• Utilized an experimental NMR technique involving the creation of "holes" in proton magnetization.
• Applied this method to cementitious solids hydrated with oxygen-17 (¹⁷O)-enriched water.
• Performed measurements under quasistatic conditions.

Main Results:

• Determined the proton spin diffusion coefficient for hydrated tricalcium aluminate to be 240 ± 40 nm²/s.
• Determined the proton spin diffusion coefficient for hydrated tricalcium silicate to be 140 ± 20 nm²/s.
• Successfully applied the novel NMR method to quantify spin diffusion in complex hydrated inorganic materials.

Conclusions:

• The developed NMR method is effective for measuring spin diffusion coefficients in disordered cementitious solids.
• This technique provides valuable quantitative data on the spatial distribution of protons in hydrated inorganic oxides.
• The findings contribute to a better understanding of hydration and crystallization processes in cementitious materials.