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CHAPTER 3 SYNTHETIC FE-CONTAINING HYDRATES Fig. 57. From the data of Atkins et al. [117] a significantly higher solubility product (log Ks0 = -27.20 and -28.09) was obtained for C3ASH4 indicating a lower stability. The samples from the study of Atkins et al. [117] had been equilibrated for 10 weeks and 6 months at 25 °C under oversaturation. Jappy et al. [110] determined the solubility at 95 °C under oversaturation for C3AS0.09H5.82, C3AS0.76H4.48 and C3AS1.14H3.72. The calculated solubility products (log Ks0 = -25.02, -27.19 and -29.96) decrease strongly with increasing silica content as shown in Fig. 57. Thus, the solubility products calculated from different studies are significantly dependent on the amount of silica, temperature and the experimental conditions (oversaturation or undersaturation) employed. The values determined in this study at undersaturation experiments (equilibration time 4 months) are similar to the values of Atkins et al. [117] obtained at oversaturation and clearly higher than the values obtained at undersaturation experiments where the solids had been equilibrated for 4 weeks [7, 112] as shown in Fig. 57. This could be related to the longer equilibration time and the amount of silica present in the solids. 127
logKs0 -20 -22 -24 -26 -28 -30 -32 Si 0.8 CHAPTER 3 SYNTHETIC FE-CONTAINING HYDRATES Si 0.84 Si 0.41 Si 0.8 Si 1.0 Si 1.0 Si 0.41 Si 1.0 C 3AH 6 Si 0.41 Si 0.84 Si 0.8 0 10 20 30 40 50 60 70 80 90 100 Temperature [°C] C 3AS 0.41H 5.18 C 3AS 0.84H 4.32 Si 0.8 Si 0.8 Si 0.09 Si 0.76 Si 1.14 Atkins 1992 Jappy 1991 Bennet 1992 this study Matschei 2007 Fig. 57 Comparison of published solubility products of Al-Si-hydrogarnet calculated in this study from the data reported in [7, 110, 112, 117], C3AH6 (dashed line), C3AS0.41H5.18 (solid line), C3AS0.84H4.32 (dotted line). The solubility products calculated from the solution composition determined at 20 °C and 25 °C were also plotted as a function of the silica content. Note that the solubility product of C3AS3 (logKs0= -41.78 and -38.6) was calculated from fG° = -6278.50 kJ/mol (Robie et al [121]) and fG° = -6260.55 kJ/mol (Sverjensky et al. [122] ) using the following equilibration reaction: Ca3Al2Si3O12 + 2H2O ↔ 3Ca 2+ + 2AlO2 - + 3HSiO3 - + OH - The thermodynamic data of water and the dissolved species used in the above reaction were taken from the GEMS thermodynamic database [121-125]. Fig. 58 shows that the solubility product decreases strongly with increasing silica content. This confirms that the 128
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Fe-containing hydrates and their fa
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The measured composition of the liq
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ZUSAMMENFASSUNG Thermodynamische Mo
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konnten die Fe-haltigen Hydrate im
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I owe to thank all the laboratory t
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Table 19 Compositions of Al/Fe-mono
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LIST OF FIGURES Fig. 1 Calculated v
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Fig. 34 Calculated solubility produ
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Fig. 62 Calculated solubility produ
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Table of Contents TABLE OF CONTENTS
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TABLE OF CONTENTS 3. SYNTHETIC FE
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TABLE OF CONTENTS 3.5.4. Solid solu
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1 INTRODUCTION CHAPTER 1 INTRODUCTI
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CHAPTER 1 INTRODUCTION be formed. T
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cm 3 /100 g cement 85 80 75 70 65 6
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CHAPTER 1 INTRODUCTION 1.4 Characte
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CHAPTER 1 INTRODUCTION Fig. 4 Sampl
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CHAPTER 1 INTRODUCTION Identificat
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CHAPTER 2 MATERIALS AND METHODS han
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3CaOAl2O3 + 6H2O → 3CaOAl2O36H2O
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CHAPTER 2 MATERIALS AND METHODS Tab
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CHAPTER 2 MATERIALS AND METHODS 2.2
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CHAPTER 2 MATERIALS AND METHODS fil
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CHAPTER 2 MATERIALS AND METHODS at
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CHAPTER 2 MATERIALS AND METHODS the
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CHAPTER 2 MATERIALS AND METHODS 0 t
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CHAPTER 2 MATERIALS AND METHODS Tab
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CHAPTER 2 MATERIALS AND METHODS 2.3
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CHAPTER 2 MATERIALS AND METHODS The
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CHAPTER 3 SYNTHETIC FE-CONTAINING H
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a). b). CHAPTER 3 SYNTHETIC FE-CONT
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o layer thickness (A) 8.0 7.8 7.6 C
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Phase log KSo CHAPTER 3 SYNTHETIC F
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volume [cm 3 ] 700 600 500 400 300
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Page 182 and 183: (Al+Fe)/Ca (Al+Fe)/Ca 0.8 0.6 0.4 0
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Early reaction CHAPTER 4 FE-CONTAIN
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weight loss in % differentiated rel
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CHAPTER 4 FE-CONTAINING HYDRATES IN
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5. GENERAL CONCLUSION AND OUTLOOK a
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Speciation of iron(III) in hydrated
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5. GENERAL CONCLUSION AND OUTLOOK
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Techniques XRD X-ray diffraction TG
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APPENDIX APPENDIX Appendix A: Addit
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Intensity (arb. Units) P Fe 2O 3 R
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APPENDIX Appendix B7 XRD patterns o
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REFERENCES REFRENCES [1] H.F.W. Tay
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REFRENCES [29] M. Vespa, R. Dähn,
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REFRENCES [54] M. Balonis, B. Lothe
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REFRENCES [81] H.F.W. Taylor, Cryst
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REFRENCES [107] K. Kyritsis, N. Mel
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REFRENCES [134] M. Wilke, F. Farges
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CURRCULUM VITAE Curriculum Vitae Na
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