An NMR Relaxation Method of Characterizing Hydrogen-Bearing Crystalline Solid Phases in Hydrated Cement Paste

• Published in: IEEE transactions on instrumentation and measurement Vol. 71; pp. 1 - 9
• Main Authors: Wu, Zhengxiu, Lu, Rongsheng, Jiang, Xiaowen, Wang, Junnan, Chen, Yi, Feng, Pan, Xie, Zonghai Harry, Ni, Zhonghua, Yi, Hong, Xiao, Dan
• Format: Journal Article
• Language: English
• Published: New York IEEE 2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">T ₁–<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">T ₁ₛ relaxation method; Cement; Cement paste; Correlation; Crystal structure; Crystalline solid phases; Crystallinity; Ettringite; hydrated cement paste; Hydrogen; Magnetization; Matter & antimatter; NMR; Nuclear magnetic resonance; nuclear magnetic resonance (NMR); Phase measurement; Probes; quantitative measurement; regression analysis; Relaxation method (mathematics); Solid phases; Solids
• ISSN: 0018-9456; 1557-9662
• DOI: 10.1109/TIM.2021.3137163

Nuclear magnetic resonance (NMR) relaxometry techniques have been widely used for evaluating hydrated cement paste as non-destructive and quantitative measurements. The important crystalline solid phases, such as Portlandite and Ettringite, are formed in the hydration of cement paste. However, it is challenging to quantify these crystalline solid phases by conventional NMR relaxation methods, due to their short-lived NMR signal lifetimes. A novel method for 2-D NMR <inline-formula> <tex-math notation="LaTeX">T_{1} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">T_{\mathrm {2S}} </tex-math></inline-formula> measurement of hydrated cement paste is proposed in this article. Combining a homebuilt NMR probe with short deadtime and high sensitivity, the <inline-formula> <tex-math notation="LaTeX">T_{1} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">T_{\mathrm {2S}} </tex-math></inline-formula> method can provide a more complete assessment of hydrogen-bearing crystalline solid phases (i.e., Portlandite and Ettringite) in hydrated cement paste. Experimental results demonstrated that the proposed method produced two additional distinct peaks in the <inline-formula> <tex-math notation="LaTeX">T_{1} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">T_{2} </tex-math></inline-formula> correlation map, compared with conventional methodologies. The attribution of the two peaks to Portlandite and Ettringite in hydrated cement paste was confirmed by heating experiments and partial least-square regression (PLSR) method. This technique has enabled detection and quantification of Portlandite and Ettringite in hydrated cement paste.