X-Ray Phase Analysis of High-Aluminate Cements under Conditions of early Compression

Abstract

Study of the structure of cementitious composites under conditions of early-age compression is essential for development of measures to improve their response to mechanical and physical impact at the earliest stage of hardening. The article considers the influence of early-age compression on the structure of high-aluminate cement which has been studied using X-ray phase analysis. Concrete mixes with different water-cement ratio have been designated as targets for research. It has been established that the age of the cement to the moment of load application impacts on composition of formed hydrates, as well as on amorphousness of the structure of high-alumina cement stone. Compression at a very early age leads to an increase in the number of peaks related to hexagonal hydroaluminates and aluminum hydroxide. Load impact results in various recrystallization behaviors. Transformation of hexagonal hydroaluminates into cubical ones is proceeding faster with growth of water-cement ratio in the samples under compression. This is illustrated by an increase of a number of related peaks in X-ray patterns. Notation: C=CaO; A=Al2O3; H=H2O; S=SiO2; M=MgO.

Specifics of Structure Formation of Cement Stone with Silica Raw Material - A Substrate of Photocatalytic Composite Material

“…Despite the initial inertness of titanium oxide, PCM, due to the presence of a silica part, can be active towards the components of the hydrating cement. In order to further use PCM in the composition of cement composites, it is necessary to study its effect on phase-forming processes, which, in turn, affect the system at various stages and contribute to the formation of the final characteristics of finished products [16][17][18].…”