Study on the hydration mechanism of a hardened slag-based plugging agent activated by alkalis

Reinforcing Mechanism of Reduced Graphene Oxide on Flexural Strength of Geopolymers: A Synergetic Analysis of Hydration and Chemical Composition

“…As a result, the second peak represents the acceleration stage of the hydration process. It should be noted that the second peak in this study occurs approximately 20,000 s after mixing, whereas the second peak for waterglass-activated geopolymers in other studies was detected after approximately 100,000 s or even later [31][32][33]. According to Zhou et al [30], this difference can be attributed to the different compositions of the alkali activators used.…”

“…In the 29 Si MAS NMR spectra shown in Figure 8a-c, Q n (mAl) notation (n = 0-2, m = 0-n) is used to describe the chemical conditions of Si nuclei, where n indicates the number of adjacent Si connected directly to one tetrahedral Si, and m represents the number of Al substitutions to the adjacent Si. Here, Al can replace Si in a disorderly manner since the particle radius of Si is similar to that of Al in the silicate structure [32]. As shown in the figures, the peak at around −79.0 ppm can be attributed to the Q 1 (0Al) sites, which represent the end-of-chain silicate tetrahedrons of the C-(A)-S-H (C-S-H or C-A-S-H) gels [41].…”

Effect of Natural Zeolite on Pore Structure of Cemented Uranium Tailings Backfill

“…In the FTIR spectrum of the hydration products of the AASP with a natural zeolite content of 0%, the main characteristic peak was located at 964.50 cm −1 . Shi et al [29][30][31][32] reported that the main cementing components of geopolymer and alkali-activated slag may be C-A-S-H or sodium aluminosilicate hydrate (N-A-S-H), and the 960-970 cm −1 peak is generally ascribed to the asymmetric stretching vibration of Si-O in hydrated calcium silicate hydrate, and the calcium ions promote the formation of a C-(A)-S-H structure. According to the main characteristic peaks in the spectrum and the chemical composition of the slag materials, it was concluded that the hydration products were mainly C-(A)-S-H gels.…”

Mechanism for the promotional effect of a novel solidifiable spacer fluid system on the cementation quality of cement sheath/formation interface

“…The figure shows that the filter cake was mainly composed of clay minerals and weighting materials, with the former mainly consisting of Al 2 O 3 , Fe 2 O 3 , and SiO 2 and the latter mainly BaSO 4 . Further analysis revealed that, in addition to the above substances, the filter cake contained C-S-H gel, 20,32,33 which suggested that it underwent the hydration and solidification reactions of inorganic gel precursors. As shown above, the microscopic analysis confirmed that the solidifiable spacer fluid remained on the surface of the filter cake where it was bonded and mixed with the virtual filter cake.…”

“…However, different from MTC technology, it does not need to modify drilling fluid or to provide zonal isolation in long term as cementing fluid, which avoids the brittle fracture of solidified body, instead its high alkalinity and solidification ability to fuse and solidify the virtual filter cake. Based on the results of previous studies, [19][20][21][22] an appropriate formula was designed for the proposed space fluid to have good compatibility with the drilling fluid and cement slurry. Compared with conventional spacer fluids, the proposed spacer fluid could improve the shear strength at the interface by 110%.…”