INVESTIGATION OF ETTRINGITE BINDER HYDRATION AT EARLY AGE FOR GLASS FIBER REINFORCED CONCRETE APPLICATION

摘要

In the context of sustainable development, reducing the thickness of architectural or structural elements is an alternative way to decrease raw material consumption and carbon dioxide emissions. The development of Glass Fiber Composite based on mineral ettringite binder is proposed to achieve this goal. These materials are based on reactions between calcium aluminate cement (CAC) and calcium sulfate (C$). The macroscopic properties (dimensional variations and mechanical properties) are extremely dependent on the nature of raw materials used and on the mass ratio between them. In this study mechanical properties are established. In order to explain the various behaviors observed, a study by infrared spectroscopy is used to follow the hydration of an ettringite binder at early age. This investigation is realized with continuous and in-situ recording. The kinetics of raw materials consumption and hydrates formation are well defined. The aim hydrates formed are ettringite and aluminum hydroxide. The influence of the ratio between CAC and C$, and on the kind of C$ used (anhydrite or plaster) are observed. These results obtained by in-situ infrared spectroscopy are confirmed by thermal analysis.