Structure and phase relations of calcium silicate hydrate and related phases in the system: Calcium oxide-aluminum oxide-silicon oxide-water.

摘要

Portland cement consists of predominantly lime, silica and alumina and is the most widely used building material in the world today. The hydration of portland cement results in the formation of different phases including calcium silicate hydrate (C-S-H) which is the principle binding phase in cement based materials. An understanding of the structure and phase relations of C-S-H is important since it is responsible for the physical and mechanical properties of cement based materials.;Several experiments were designed to study the structure and phase equilibria of C-S-H. A common set of characterization methods was used, when applicable, to study the samples. They include pH measurements, x-ray diffraction analysis, electron microscopy, thermogravimetric analysis, chemical analysis, ;Series of mixtures, with 0, 10 or 20 wt.% Al;Controlled pH hydration experiments were performed on a commercial tricalcium silicate and a laboratory synthesized alite. These were hydrated at different pHs for various lengths of time. Studies showed that two C-S-H phases exist and that a pH of ;Stratlingite was found to be a persistent coexisting phase with the two C-S-H phases. It was synthesized both from phase pure oxides and metakaolinite, calcium aluminate cement, lime and 0.2N sodium hydroxide. They were hydrothermally treated modestly and then studied. Results were compared with other published data.;A study was done on the formation of gel-like phases within the system Al