Silicate Anion Structural Change in Calcium Silicate Hydrate Gel on Dissolution of Hydrated Cement.

Haga, Kazuko; Shibata, Masahito; Hironaga, Michihiko; Tanaka, Satoru; Nagasaki, Shinya

doi:10.3327/jnst.39.540

Cited by 17 publications

(17 citation statements)

References 4 publications

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“…This suggests that the chemical and C/S 0.7 is 3.2 and 18.6 respectively by previous report [44]. It is also reported that Q2/Q1 ratio increase with the progress of leaching [5], the progress of polymerization of silicate by calcium leaching is reported by previous reports [45,46]. Fig.7 plots Q 1 /∑Q i versus the C/S ratio for C-S-H, the values determined in this study and for 1.4nm…”

Section: Nmr Measurementssupporting

confidence: 74%

Deteriorated hardened cement paste structure analyzed by XPS and 29Si NMR techniques

Kurumisawa

Nawa

Owada³

et al. 2013

Cement and Concrete Research

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In this report, X-ray photoelectron spectroscopy (XPS) and 29 Si-MAS-NMR was used for the evaluation of deteriorated hardened cement pastes. The deterioration by ammonium 2 nitrate solution was accompanied by changes in the pore structure as well as by structural changes in the C-S-H in the hardened cement paste. The CaO/SiO2 ratio of the C-S-H decreased with the progress of deterioration, there was also polymerization of the silicate in the C-S-H. It was confirmed that the degree of polymerization of silicate of the C-S-H in hardened cement paste can be determined by XPS. It was also shown that the polymerization depends on the structure of the C-S-H.Keywords: Calcium-Silicate-Hydrate (C-S-H)(B); Degradation(C); 29 Si NMR; X-ray photoelectron spectroscopy; CaO/SiO2 ratio 3

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Section: Nmr Measurementssupporting

confidence: 74%

Deteriorated hardened cement paste structure analyzed by XPS and 29Si NMR techniques

Kurumisawa

Nawa

Owada³

et al. 2013

Cement and Concrete Research

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“…Generally, C-S-H gel, as a primary hydrated mineral in HCP, mainly consists of the dimer and chain of silicate anion, which are presented by the spectrum of Q 1 and Q 2 in terms of the method of 29 Si MAS-NMR [12,13]. After high temperature exposure at 450 and 750 • C in turn, the spectrum of Q 2 and Q 1 gradually disappears instead of the new dimer and monomer of Q 1 N and Q 0 N [4] as shown in Figure 5(a).…”

Section: Initial Setting Time Of Dcpmentioning

confidence: 99%

Rehydration activity of hydrated cement paste exposed to high temperature

Xuan

Shui

2010

Fire and Materials

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SUMMARYSubjected to the wet surrounding, hydrated cement paste (HCP) exposed to high temperature may exhibit rehydration behavior. This paper presents the influence of the dehydration temperature and the initial water/cement ratio on the rehydration activity of dehydrated cement paste (DCP). Original HCPs were prepared with two water/cement ratios of 0.3 and 0.5, respectively, and cured under the fog-spraying standard condition for 30 days. The DCP powders used were obtained by grinding dry HCP less than 75 m and then subjecting to different temperatures, up to 900 • C. The rehydration properties of DCP were evaluated by the required water for standard consistency, the setting time, the rehydrated compressive strength and the microstructure evolution. X-ray diffraction (XRD) was employed to identify the crystalline phases before and after rehydration. Experimental results showed that the coupled rehydration effect from the dehydrated hydration products and the initially unhydrated cement determined the rehydration behavior of DCP. The rehydration of DCP strongly depended on the dehydration temperature and the water/cement ratio of the original HCP.

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“…8). This may indicate the formation of hydraulic products (calcium silicate hydrates and calcium aluminate hydrates) formed by the reaction with lime and pozzolanic fine aggregates [20]. Formation of these compounds provides strong adhesion bonds which make the mortar durable and stiff.…”

Section: Characteristics Of Roman Mortarsmentioning

confidence: 99%

Properties of Roman bricks and mortars used in Serapis temple in the city of Pergamon

Özkaya

Böke

2009

Materials Characterization

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Serapis temple, which was constructed in the Roman period in the city of Pergamon (Bergama/Turkey), is one of the most important monuments of the world heritage. In this study, the characteristics of bricks and mortars used in the temple have been determined in order to define the necessary characteristics of the intervention materials, which will be used in the conservation works of the temple. Several analyses were carried out to determine their basic physical properties, raw material compositions, mineralogical and microstructural properties using X-ray diffraction, Scanning Electron Microscope and a Thermo Gravimetric Analyzer. Analysis results indicated that the mortars are stiff, compact and hydraulic due to the use of natural pozzolanic aggregates. The Roman bricks are of low density, high porosity and were produced from raw materials containing calcium poor clays fired at low temperatures.

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Silicate Anion Structural Change in Calcium Silicate Hydrate Gel on Dissolution of Hydrated Cement.

Cited by 17 publications

References 4 publications

Deteriorated hardened cement paste structure analyzed by XPS and 29Si NMR techniques

Deteriorated hardened cement paste structure analyzed by XPS and 29Si NMR techniques

Rehydration activity of hydrated cement paste exposed to high temperature

Properties of Roman bricks and mortars used in Serapis temple in the city of Pergamon

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