NMR relaxation of molecules confined inside the cement paste pores under partially saturated conditions

The Effect of Silica Fume and Organosilane Addition on the Porosity of Cement Paste

“…As a non-polar liquid, cyclohexane has been used previously in exploring the pore structure of hydrated cement paste [28]. It was shown that it only fills the capillary and inter-C-S-H pores, which can be observed in the T2 distribution at longer times (from 2 ms up to 100 ms in Figure 3).…”

“…One can observe two distinct relaxation components in the early hydration stages that merge in a broader distribution after the acceleration stage of hydration (6 h in the case of the sample in Figure 1). The main component at the beginning of hydration, arising at long relaxation times and with a larger area, slowly shifts towards shorter values as water from the capillary pores becomes chemically bound in C-S-H and physically confined between C-S-H layers, as demonstrated by the decrease in the peak area [28,31]. It is possible to extract the T 2 values of the peak maximum, as there are no significant differences between the peak widths for these samples (see Figure 1).…”

“…The small reduction of the relaxation time by silica fume addition can be explained by the presence of paramagnetic impurities in their structure, which act as relaxation centers for water molecules, additionally contributing to the relaxation mechanism [32]. This enhancement of the relaxation rate by the presence of SF particles is apparent until the intra-and inter-C-S-H contributions to the signal can no longer be neglected [28]. The effect of SF particles on reducing the relaxation rate can be neglected when these latter contributions become dominant and as the SF particles start to react with the newly formed calcium hydroxide (CH).…”

Method Development and Surface Utilization: Monitoring Environment in Urban Society Through Analytical Chemistry

“…Beside the computer modelling, the use of modern instrumentation is also demanding to give specific information from a different point of view. The information gained from the nuclear magnetic resonance (NMR) relaxation of proton nuclei absorbed in cement porous media was reported (Ardelean, 2019; Bede, et al, 2016). Such information is useful in designing of new types of cement-based materials, with lower ecological fingerprint, to be used for urban society development.…”

“…Some case studies in partially filled porous silica glasses were performed using NMR relaxation and diffusion techniques (Mattea et al, 2004). Analysis of cement materials was also done by NMR relaxometry techniques giving thorough understanding of the water behavior inside the pores (Bede et al, 2016). In the future, material's interface becomes important for many purposes.…”