Reply to Zhou et al.'s “A discussion of the paper “Dynamic microstructural evaluation of hardened cement paste during first drying monitored by 1H NMR relaxometry””

The Relative Humidity Range for the Development of Irreversible Shrinkage in Hardened Cement Paste

“…The mass reduction in the re-humidifying process can be explained by the hypothesized inequivalent condition associated with the dynamic microstructural change. In previous experiments using 1 H NMR relaxometry, it was confirmed that layered C-S-H agglomeration structures contain gel pore spaces and interlayer spaces (McDonald et al 2007), and that the slit size in the pore structure dynamically changes according to the drying state (Maruyama et al , 2020. Due to the narrowing of gel pores in the higher relative humidity range above 80% RH followed by the narrowing of the interlayer spaces below 80% RH, the moisture transport changes dramatically, as confirmed by previous studies [refer to Figs.…”

“…Below 30% RH, there was no change in S H2O . When the strain data, BET surface area change after long-term drying, and recent data of 1 H NMR relaxometry results (Maruyama et al , 2020) are compared, a new view of C-S-H alteration is obtained. Based on the 1 H NMR relaxometry, above and equal to 80% RH, T 2 (a decay constant for transverse components of magnetization decay process) of interlayer space in C-S-H will not be changed during the drying.…”

Microstructural Analysis of Cement Paste Blended with Blast Furnace Slag Using 1h Nmr Relaxometry

“…Muller et al [30] reported T 2 surf to be 75 μs and used the diameter of water molecule, 0.28 nm for ε thereby giving λ = 3.73 × 10 − 3 nm/μs. Recently, Maruyama et al [23] reported λ = 2.7 × 10 − 3 nm/μs based on the BET surface area and regression analysis and Naber et al [25] reported T 2 surf to be 310 μs and thereby λ = 9.0 × 10 − 4 nm/μs. Former studies have reported much higher values of surface relaxivity in the range of 7.5 × 10 − 3 to 2.8 × 10 − 2 nm/μs [18,19,27].…”

“…Therefore, 1 H NMR relaxometry serves as a well-suited tool to probe the full range of pores in the cement paste, spanning several orders of magnitude. The technique has been applied to monitor the hydration of cement [7][8][9][10][11][12][13][14][15][16][17], to measure the surface area and to determine the pore size distribution [9,[18][19][20][21][22][23][24][25][26]. The water population in the various pores has been quantified [27,28] and further used to determine the solid and bulk density of C-S-H [29][30][31][32].…”

Distribution and Dynamics of Water in the Blended Pastes Unraveled by Thermoporometry and Dielectric Properties

“…The moisture distribution in hcp under different RH levels is a complex problem since the volume of nanosized pores show dynamical changes during the drying process. There was a debate about whether the volume of gel pores would be largely increased by drying under 85 % RH [23,24], in which the different criteria for classification of gel pores also elevated the contradiction in understanding the dynamic process. The concept of gel pores in hcp was originally proposed by T.C.…”