Quantitative evaluation of hydrated cement modified by silica fume using QXRD, 27Al MAS NMR, TG–DSC and selective dissolution techniques

Wei, Yongqi; Yao, Wu; Xing, Xiaoming Li Zhenyu Wen Yi Li Weian Wang Xiangdong; Wu, Manjian

doi:10.1016/j.conbuildmat.2012.06.075

Cited by 100 publications

(31 citation statements)

References 28 publications

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“…It should be also noted that the results in Tables 5 and 6 also include 20% Al 2 O 3 which is used as a standardization. In the XRD results, the unhydrated cement clinkers C 3 S, C 2 S, C 3 A and C 4 AF, as well as the hydration products Ca(OH) 2 and ettringite are all achieved [36]. The mullite and quartz come from the crystalline phase of the unhydrated FA [61].…”

Section: Hydration Process By Xrd Rietveld Analysismentioning

confidence: 91%

“…Twenty percent of Al 2 O 3 (by weight) was mixed with the samples to correct the proportion of the mineral phases. The XRD patterns were refined by the Rietveld method according to the reference [27,[34][35][36], using the software TOPAS (Total Pattern Solution). The crystallographic models for the Rietveld refinement were mostly downloaded from Crystallography Open Database, except the one of Friedel's salt was collected from the reference [37].…”

Section: Xrd Rietveld Analysismentioning

confidence: 99%

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Pozzolanic reaction of fly ash modified by fluidized bed reactor-vapor deposition

He-hua

et al. 2017

Cement and Concrete Research

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Section: Hydration Process By Xrd Rietveld Analysismentioning

confidence: 91%

Section: Xrd Rietveld Analysismentioning

confidence: 99%

Pozzolanic reaction of fly ash modified by fluidized bed reactor-vapor deposition

He-hua

et al. 2017

Cement and Concrete Research

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“…By comparing the peaks for CNCC1 at 56 and 236 days it can also be seen that the XRD peak of CNCC1 at 236 days at 2 of 31 o is slightly higher than at 56 days indicating the formation of more C-S-H and consumption of CH after 236 days. The reduction of C 3 S peak of CNCC1 at 236 days at 2 of 29.4 o compared to the same at 56 days and cement paste is another indication of pozzolanic and hydration reaction [41]. Shaikh et al [42] reported in their XRD results that after 28 days the cement paste containing 2% nano-silica exhibited less calcium hydroxide peaks than the control cement paste.…”

Section: Porosity Of Nanocompositesmentioning

confidence: 91%

Effect of calcined nanoclay on microstructural and mechanical properties of chemically treated hemp fabric-reinforced cement nanocomposites

Hakamy

Shaikh

Low

2015

Construction and Building Materials

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Cement nanocomposites reinforced with hemp fabrics and calcined nanoclay (CNC) have been fabricated and investigated. The treated hemp fabric-reinforced cement composites and nanocomposites were subjected to 3 wetting and drying cycles and then tested at 56 and 236 days. The influences of CNC dispersion on the durability of these composites have been characterized in terms of porosity, flexural strength, stress-midspan deflection curves and microstructural observation of hemp surface. The microstructure of matrix was investigated using X-ray Diffraction. Results indicated that the CNC effectively mitigated the degradation of hemp fibre. The durability and the degradation resistance of hemp fibre were enhanced due to the addition of CNC into the cement matrix and the optimum content of CNC was 1 wt%.

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“…In the one-day material, however, the amount of portlandite was higher in the blended paste. This may very likely have been due to the fact, reported by some authors [16], that nSA can adsorb Ca 2+ ions onto its surface, inducing C 3 S re-dissolution and the concomitant formation of more C-S-H gel and portlandite, as per Equation 1. It further revealed that the water bonded to the C-S-H gel, defined as the total water loss less the loss in the AFt/AFm/CH phases, and carbonate loss of CO 2 were greater in the pastes containing nSA (Figure 11).…”

Section: Effect Of Nsa On Late Age Hydrationmentioning

confidence: 99%

Effect of the addition of nanosilica on white cement hydration at 25°C

Bosque

Martínez-Ramírez

Martín-Pastor³

et al. 2014

MATEC Web of Conferences

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Abstract. The cement industry is keen on reducing natural resource consumption, reusing waste that would otherwise be sent to a rubbish tip and lowering its CO 2 emissions. In pursuit of those objectives, the addition of materials such as silica fume, ceramic waste, rice husk and precipitated or colloidal nanosilica, in the various stages of cement manufacture has become increasingly common. That practice inspired the present study (using isothermal conduction calorimetry, 29 Si and 27 Al MAS NMR, XRD and DTA/TG) of the effect of precipitated amorphous nanosilica (10 wt%) on white portland cement (WPC) hydration. The isothermal conduction calorimetry findings, which were consistent with the NMR and DTA/TG results, showed that adding amorphous nanosilica altered reaction kinetics, expediting alite and belite hydration. The addition also intensified the heat flow attributed to alumina phase hydration and brought the respective peak forward. Although no general consensus has been reached in the literature on the attribution of the third peak appearing on the calorimetric curve for WPC, based on the present findings, the main aluminate hydrate product is monosulfoaluminate. Furthermore, a pre-peak inflection point on the profile of the first exothermal peak on the WPC calorimetric curve was interpreted as the beginning of the pozzolanic reaction, which accelerates alite hydration, consuming portlandite and raising the heat released. C-S-H gel nanostructure was also modified. The results revealed a linear relationship in both the blended and the pure cement pastes between the degree of hydration and the number of Q 1 and Q 2 units in the gel. The presence of Q 2 units was much greater and of Q 1 units slightly lower in the former than in the latter.

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Quantitative evaluation of hydrated cement modified by silica fume using QXRD, 27Al MAS NMR, TG–DSC and selective dissolution techniques

Cited by 100 publications

References 28 publications

Pozzolanic reaction of fly ash modified by fluidized bed reactor-vapor deposition

Pozzolanic reaction of fly ash modified by fluidized bed reactor-vapor deposition

Effect of calcined nanoclay on microstructural and mechanical properties of chemically treated hemp fabric-reinforced cement nanocomposites

Effect of the addition of nanosilica on white cement hydration at 25°C

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