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Cement Analysis – Solid-state ¹H, ²⁹Si, ²⁷Al NMR

Cement is the most common building material used today, however, its first use dates back to the ancient Romans. Today, the growing attention to environmental protection and resource conservation require finding new solutions to reduce the environmental impact of cement’s production processes.

The performance of construction products in the cement matrix (processability, mechanical strength, durability) are the result of the complex system of reactions that occur when cement reacts with water: cement minerals, mainly silicates and aluminates, undergo chemical transformations that lead to the development of new hydrated minerals which grow and harden over time. Hydration of cement results in a complicated multicomponent (crystalline and amorphous), heterogeneous and non-equilibrium solid-state material matrix, in which reacting interfaces between different components play large roles. ssNMR spectroscopy is an ideal tool for the study of such complicated systems, thanks to the nuclear spin selectivity, where only one nuclear-spin isotope (e.g., ¹H, ²⁷Al, ²⁹Si,…) is independently detected and analyzed at a time, and to the fact that the resonances from these spins reflect the local structure.

Another area in which the study of ssNMR spectroscopy could be extremely useful is that concerning the phenomena of degradation of cementitious materials (carbonation, Chloride attack, Sulfate attack, etc.,). The fact that the building materials are continually subjected to the action of atmospheric agents may cause serious damage to structures resulting in increased maintenance costs and reduction of the life time of the buildings. Multi-nuclear ssNMR analysis involving nuclei such as ¹H, ¹³C, ²⁷Al and ²⁹Si can reveal the level of structural destructions, responsible phases and the preventive actions that would help to avoid concrete degradations.