High pressure synchrotron X-ray diffraction study of calcium silicate hydrates and alkali-activated inorganic binders

The major objectives of this thesis are as follows: (1) to explore the possible identity of reaction products of alkali-activated inorganic binders and (2) to obtain the bulk moduli of those products by means of synchrotron X-ray diffraction using diamond anvil cells to generate high-pressure.The extensive literature survey suggests that the identity of the geopolymer reaction product may be in a form of disordered single layers consisting of six-membered rings, which is a typical building unit of the ABC-6 family of zeolites framework. Based on the results, alkali-activated fly ashes and slag were selected to be examined by synchrotron X-ray diffraction. The similarities and differences between various binders formed in the samples were investigated particularly for those binders activated by Na-based activators, such as NaOH, sodium silicate or a mixture of these two components at 80°C. The results confirm that the C-S-H (I) phase is a major phase in the alkali-activated slag system and also give support to the suggested identity of Na-based geopolymer (i.e., a disordered form of the ABC-6 family type of zeolite), demonstrated by the detection of a large presence of the hydroxycancrinite phase, one of the ABC-6 family of framework type zeolites, in the samples.The second objective of this thesis was to determine experimentally the bulk moduli of the selected representatives of reaction products of alkali-activated inorganic binders [tobermorites (14A, 11A, and 9A types), synthetic C-S-H (1), alkali-activated slag C-S-H (1) and hydroxycancrinite] using high pressure synchrotron X-ray diffraction.Measurements of the bulk moduli of the materials are as follows: (1) 14 A tobermorite : 84 +/- 3 GPa with K'o = 4 +/- 2 (2) 11 A tobermorite : 118 +/- 4 GPa with K'o = 4 +/- 2 (3) 9 A tobermorite : 88 +/- 6 GPa with K'o = 5 +/- 3 (4) Synthetic C-S-H (I) : 35 +/- 5 GPa (K'o = 4.00, assumed) (5) Alkali-activated slag C-S-H (I) : 33 +/- 3 GPa (K' o = 7 +/- 3, calculated) : 35 +/- 1 GPa (K'o = 4.00, assumed) (6) Hydroxycancrinite : 45 +/- 2 GPa with K'o = 4 +/- 1.