FORMATION OF MICRO-DISPERSION STRUCTURES OF CONSTRUCTION MATERIALS

Abstract

When using inorganic binders, the processes of their interaction with water or aqueous solutions of salts are most characteristic. In order for the corresponding interaction processes to proceed sufficiently intensively, a high reactivity of binders to water or aqueous solutions of salts is necessary. This is achieved, in particular, due to the large specific surface area of the finely ground binder, the creation of a favourable temperature and humidity regime, addition of additional ingredients, if necessary, etc. When using organic binders, the most characteristic processes during structure formation and hardening are micellization, solvation, diffusion in films, polymerization and evaporation of liquid hydrocarbons. The aim of the research is the chemical interaction of cement with water, the rate of change of the pH of the cement paste, the processes of hydrolysis and hydration of Portland cement. The research objectives are the processes of hydrolysis and hydration of Portland cement, hydrated neoplasms and their concentration in an aqueous alkaline medium. The processes of hydrolysis and hydration of Portland cement, as well as other binders relate to heterogeneous, exothermic ones and occur, as a rule, in non-isothermal conditions, therefore, the main chemical reactions accompanied by a change in pH are associated with the simultaneous occurrence of heat transfer and mass transfer, i.e. with phase changes. The occurrence of a phase from supersaturated solutions underlies the formation of condensation-crystallization structures during hardening of mineral binders. The raw materials in powder form are mixed with water until a paste is obtained, which after a while hardens. Clinker minerals do not interact with water at the same speed. Calcium aluminates interact with water faster than the others. Thus, with the help of additives of surface-active substances, thermal regime, by changing the nature of compaction, it seems possible to directionally control the formation of the structure taking into account the chemical and mineralogical composition of the cement used.