Hydration of Portland cement followed by29Si solid-state NMR spectroscopy

Solid state NMR investigations on the role of organic admixtures on the hydration of cement pastes

“…Several contributions to the hydration and hardening of cement pastes as determined by using 27 Al and 29 Si NMR methods are available in the literature [19][20][21][22][25][26][27][28]. Here, we extend these to organically modified systems to monitor the influence of the organic components on the cement paste at the molecular level.…”

Interaction of TEOS with cementitious materials: Chemical and physical effects

“…4). The intense signal at around -85 ppm with a shoulder at around -79 ppm on the spectrum for the mix were respectively attributed to Q 2 (Si) and Q 1 (Si) units in C-S-H gel chains [40], along with Q 3 (Si) (≈-100 ppm) and Q 4 (Si) (≈-111 ppm) units characteristic of the polymerised consolidant.…”

“…6) exhibited signals denoting: Q 0 or isolated tetrahedra (bands from -67.3 to -76.7 ppm associated with anhydrous alite and belite); Q 1 , chain-end tetrahedra or dimers (signal at -79.2); and Q 2 , mid-chain groups (at ≈-85 ppm), both of whose adjacent tetrahedra contained silicon atoms. According to the literature, the latter two, attributed to the C-S-H gel formed during cement hydration [40,41] overlapped with a third signal at around -81 ppm, associated with Q 2 (1Al) units, i.e., mid-chain groups in which one of the adjacent tetrahedra contained aluminium. For a satisfactory fit to the curve profile, moreover, spectrum deconvolution called for the inclusion of a component at around -82.8 ppm, which might be interpreted to be due to bridging silicons (Q 2 (L) units) [42].…”

Compatibility Investigations on Polymer‐Fiber‐Reinforced Cements Modified with Polymer Latexes

“…[20] Solid-state NMR spectroscopy [21][22][23][24] was applied to monitor the bulk composition of both the hardened cement and the polymer fibers, and its changes during the hydration process, while scanning electron microscopy [25,26] enabled the visualization of the fiber surfaces, and the particle shapes of the hydrated cement phases and the latex. Several contributions to the hydration and hardening of cement pastes, as determined from 1 H, 27 Al and 29 Si NMR spectroscopy [23,24,[27][28][29][30][31][32][33] and scanning electron microscopy, and of polymer-fiber-modified cements [7][8][9] are available in the literature, and are extended to a microscopic level. In particular the 27 Al NMR signals can be correlated to defined crystal structures within the inorganic phase.…”