Effect of nano-silica on the efflorescence of waste based alkali-activated inorganic binder

Wang, Jinbang; Zhou, Tongtong; Xu, Da; Zhou, Zhen; Du, Peng; Xie, Ning; Cheng, Xin; Liu, Yu

doi:10.1016/j.conbuildmat.2018.02.006

Cited by 55 publications

(24 citation statements)

References 62 publications

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“…The first peak appears immediately after the mixing was complete, corresponding to the wetting and initial dissolution of the slag particles [27]. Most of the decomposition reaction happens in this period.…”

Section: Hydration Processmentioning

confidence: 98%

“…In theory, three distinct Al environments, namely Al(IV), Al(V), and Al(VI), can be observed in the 27 Al MAS NMR spectra of the geopolymer pastes. The peaks at approximately 74.0 ppm and 68.0 ppm, q 2 (I) and q 2 (II), are assigned to the tetrahedral Al(IV) incorporated in the C-A-S-H gels under bridging conditions [45]; the peak in the range from 30.0 to 40.0 ppm is attributed to the presence of Al(V); the peak with lower intensity in the range from 0 to 20.0 ppm is generally considered octahedral Al(VI) in AFm and/or hydrotalcite phases [46].…”

Section: Nmr Analysismentioning

confidence: 99%

“…For the 29 Si MAS experiments, the pulse width, relaxation delay, and the number of scans were 0.1 µs, 20 s, and 1000, respectively. Solid-state 27 Al MAS NMR spectra were collected at 156.4 MHz on the same instrument. The pulse width, relaxation delay, and the number of scans were 0.1 µs, 5 s, and 32, respectively.…”

Section: Nuclear Magnetic Resonance (Nmr) Testmentioning

confidence: 99%

“…The pulse width, relaxation delay, and the number of scans were 0.1 µs, 5 s, and 32, respectively. The 29 Si and 27 Al chemical shifts were referenced to the external samples of tetramethylsilane (TMS) and AlCl 3 •6H 2 O solution with a concentration of 1.0 mol/L, respectively.…”

Section: Nuclear Magnetic Resonance (Nmr) Testmentioning

confidence: 99%

“…29 Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra for (a) M0, (b) R3, (c) R4, and27 Al MAS NMR spectra for (d) M0, (e) R3, (f) R4.…”

mentioning

confidence: 99%

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

Long

Luo

et al. 2019

Nanomaterials

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With the development of nanotechnology, reduced graphene oxide (rGO) has been used to improve the flexural strength of geopolymers. However, the reinforcing mechanism of rGO nanosheets on the flexural strength of geopolymers remains unclear. Here, this reinforcing mechanism was investigated from the perspectives of hydration and chemical composition. The effect of the reduction degree on rGO-reinforced geopolymers was also studied using isothermal calorimetry (IC), X-ray diffraction (XRD), and nuclear magnetic resonance (NMR) tests. Results show that the hydration degree and flexural strength of geopolymers effectively increase due to rGO addition. After alkali reduction at a temperature of 60 °C, rGO nanosheets have maximum reinforcement on the flexural strength of geopolymers with an increment of 51.2%. It is attributed to the promotion of slag hydration, as well as the simultaneous formation of calcium silicate hydrate with low Ca/Si ratio (C-S-H(I)) and calcium aluminosilicate hydrate (C-A-S-H) phases due to the inhibiting effect of rGO nanosheets on Al substitution on the end-of-chain silicates of C-S-H and C-A-S-H gels. In addition, different reduction degrees have almost no effect on the chemical composition of rGO-reinforced geopolymers, while excessive reduction impairs the improving effect of rGO nanosheets on the hydration process and flexural strength of geopolymers due to significant structural defects.

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Section: Hydration Processmentioning

confidence: 98%

Section: Nmr Analysismentioning

confidence: 99%

Section: Nuclear Magnetic Resonance (Nmr) Testmentioning

confidence: 99%

Section: Nuclear Magnetic Resonance (Nmr) Testmentioning

confidence: 99%

“…29 Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra for (a) M0, (b) R3, (c) R4, and27 Al MAS NMR spectra for (d) M0, (e) R3, (f) R4.…”

mentioning

confidence: 99%

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