UNDERSTANDING OF REACTIONAL SEQUENCES AND LIMITING STAGES DURING TRICALCIUM ALUMINATE HYDRATION WITH AND WITHOUT GYPSUM.

International audience; The tricalcium aluminate reacts very quickly with water to form calcium hydroaluminates while the addition of calcium sulphate, leads to the formation of ettringite, with a slower process. The systematic study of the systems: “C3A” and “C3A-sulphate” by isothermal microcalorimetry and a follow up of ionic concentrations of diluted system suspensions made it possible to understand the sequence of the reactions and the limiting stages in both systems. In all cases, as it is in contact with the solution, the C3A dissolves what leads to the instantaneous precipitation of a certain quantity of calcium hydroaluminate. In case of only C3A hydration, there is then a decrease…