The kinetics of cement hydration has been studied by H1-NMR, through the analysis of the Free Induction Decay (FID) combined with quasi-continuous T1 relaxation time distributions analysis, operating a sort of 2D T1-T2 correlation analysis on a somewhat more physical than mathematical basis. The analysis allowed us to distinguish two solid components, SS (Solid-Short) with T1 of a few milliseconds and SL (Solid-Long) with T1 of the order of a second, ascribable to H1 of anisotropically bound groups in the C-S-H gel, and to H1 nuclei of the Portlandite crystals and possibly to crystal water in Ettringite crystals, respectively. A liquid-like component LS (Liquid-Short) with very short T2 (about 80 us) and T1 a few milliseconds, both quite stable during hydration, was isolated and interpreted as water confined in the interlayer spaces of the gel. Amounts of LS and SS increase together steadily during hydration, and these, divided by LL (Liquid-Long, the signal from the water in the pores), are proportional to 1/T1 for LL, confirming a surface relaxation effect for LL.
Evolution of a short-T2 liquid-like 1H signal during the hydration of White Portland Cement / Villiam Bortolotti; Robert J. S. Brown; Paola Fantazzini; Manuel Mariani. - In: MICROPOROUS AND MESOPOROUS MATERIALS. - ISSN 1387-1811. - STAMPA. - 178:(2013), pp. 108-112. [10.1016/j.micromeso.2013.03.010]
Evolution of a short-T2 liquid-like 1H signal during the hydration of White Portland Cement
BORTOLOTTI, VILLIAM;FANTAZZINI, PAOLA;MARIANI, MANUEL
2013
Abstract
The kinetics of cement hydration has been studied by H1-NMR, through the analysis of the Free Induction Decay (FID) combined with quasi-continuous T1 relaxation time distributions analysis, operating a sort of 2D T1-T2 correlation analysis on a somewhat more physical than mathematical basis. The analysis allowed us to distinguish two solid components, SS (Solid-Short) with T1 of a few milliseconds and SL (Solid-Long) with T1 of the order of a second, ascribable to H1 of anisotropically bound groups in the C-S-H gel, and to H1 nuclei of the Portlandite crystals and possibly to crystal water in Ettringite crystals, respectively. A liquid-like component LS (Liquid-Short) with very short T2 (about 80 us) and T1 a few milliseconds, both quite stable during hydration, was isolated and interpreted as water confined in the interlayer spaces of the gel. Amounts of LS and SS increase together steadily during hydration, and these, divided by LL (Liquid-Long, the signal from the water in the pores), are proportional to 1/T1 for LL, confirming a surface relaxation effect for LL.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
