Nuclear magnetic resonance study of hydration of synthetic white cement: continuous quantitative monitoring of water and Ca(OH)₂ during hydration

Abstract

The solidification of synthetic white cement is monitored by nuclear magnetic resonance. Proton signals in several different environments are resolved and the time evolution of their dynamics and relative numbers is presented. The amounts of liquid water (the water which has not yet entered the solid structure to become crystalline water) and Ca(OH)2 crystallites are monitored precisely during hydration. The technique gives a quantitative insight into the hydration process as well as the growth (and decay) pattern of various cement paste components.

Monitoring of Hydration of White Cement Paste with Proton NMR Spin–Spin Relaxation

“…2 During this period slow growth of CH platelets and ettringite occurs. 1,2 These hydration products can be identified in Figs. 2 and 3 as a solid-phase signal with combined proton fractions of 3% (crosses) and shortest T 2 .…”

“…The average surface-to-volume ratio of these pores increases, resulting in the observed decrease in the observed T 2 of this component magnetization. 1 At later hydration times ( տ 25 h) we assign this component (squares) to water in nanopores. At the same time, with increasing amount of C-S-H formed, more C-S-H interlayer spaces become available, increasing the amount of interlayer water and the corresponding proton magnetization contributing to the solidlike signal.…”

“…For example, NMR resolves protons in various states of mobility, such as in bulklike pore water, semi-liquid-like gels (namely calcium-silicate-hydrate (C-S-H) gels), and those confined in solid phases such as hydroxyl groups in calcium hydroxide (CH) and crystalline water in ettringite. 1 The parameters of interest can be monitored in a continuous fashion, limited only by the duration of a single experiment. This allows us to track the progress of the different proton groups and hence the different hydration products as the cement sets.…”

The1HT 1 study of the influence of clay addition on Portland cement hydration

“…In stage I the component (a) represents the water protons in fresh liquid paste while in later stages it is associated to water in macropores [5]. The components (b) and (c) refer to the protons of water in capillaries and gel pores, respectively [3,5].…”

“…The components (b) and (c) refer to the protons of water in capillaries and gel pores, respectively [3,5].…”