Stacking Faults of the Hydrous Carbonate-Containing Brucite (Hcb) Phase in Hydrated Magnesium Carbonate Cements

• DOI: 10.2139/ssrn.4524819
• Publication Date: 2023-07-28T22:21:18Z
• Authors: Daniel Jansen; Alexander German; Dominique Ectors; Frank Winnefeld
• Keywords: Brucite

Recently, a hydrous carbonate-containing brucite (HCB) with an approximate composition of MgCO3·35Mg(OH)2·H2O was postulated as hydration product binders based on mixtures reactive magnesia and hydromagnesite (Mg5(CO3)4(OH)2∙4H2O). X-ray diffraction showed that the 001 reflection this phase split into two reflections at 20°C, whereas 60°C only one occurred. Rietveld refinement revealed pattern HCB-phase could be fitted well when random displacement (stacking faults) movement layers in x, y z direction were allowed. The presence water and/or carbonate leads to different distances between layers, thus causing splitting reflection. At 60°C, is included structure, leading similar distance all layers. assignment additional appearing 20°C separate, unknown hydrated magnesium carbonate, suggested earlier studies, can excluded.