Influence of Minor Ions on the Stability and Hydration Rates of β-Dicalcium Silicate |
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Authors: | Young-Min Kim Seong-Hyeon Hong |
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Affiliation: | School of Materials Science and Engineering, Seoul National University, Seoul 151-742, Korea |
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Abstract: | The effects of Al3+, B3+, P5+, Fe3+, S6+, and K+ ions on the stability of the β-phase and its hydration rate were studied in reactive dicalcium silicate (C2S, Ca2SiO4) synthesized using the Pechini process. In particular, the dependences of the phase stability and degree of hydration on the calcination temperature (i.e., particle size) and the concentration of the stabilizing ions were investigated. The phase evolution in doped C2S was determined using XRD, and the degree of hydration was estimated by the peak intensity ratio of the hydrates to the nonhydrates in 29Si MAS NMR spectra. The stabilizing ability of the ions varied significantly, and the B3+ ions were quite effective in stabilizing the β-phase over a wide range of doping concentrations. The hydration results indicated that differently stabilized β-C2S hydrated at different rates, and Al3+- and B3+-doped C2S exhibited increased degree of hydration for all doping concentration ranges investigated. The effect of the doping concentration on degree of hydration was strongly dependent on the stabilizing ions. |
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Keywords: | dicalcium silicate cements dopants/doping hydration |
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