Role of potential-determining ions and water molecules in the structure formation of cement compositions

Abstract

The paper is concerned with dealing with an urgent problem of present-day construction materials science and engineering such as increasing the strength of cement stone when using finely dispersed fillers. It has been found that the physical and mechanical properties of Portland cement-based materials largely depend on the strength of the cement matrix modified by finely dispersed fillers, in particular, on the electric surface properties of all components and pore walls (equilibrium electric surface potential and double electric layer with potential-determining ions and counter-ions and at the interface between the solid phase and water). Studies were conducted to determine the values of equilibrium electric surface potentials of perlite and glass hollow microspheres. The system-forming hierarchical structure of water acting as a matrix or a crystal-forming platform for the synthesis of spatial structures during the formation of a crystalline cage on the surface of micro-fillers was substantiated. The assembly elements of these systematized structures were investigated using electron microscopy. It should be noted that when water films are supersaturated with ions during cement hydration, crystals nucleate and grow on the surface of micro-fillers, which leads to self-compaction and hardening of the cement matrix at the microlevel.