PRODUCTION VARIABLES OF FINELY DISPERSED CEMENT SYSTEMS

摘要

This article discusses production variables of finely dispersed cement systems for decorative coatings. The influence of fine grinding and modification on properties of colloidal systems is considered. It is demonstrated that intensive increase in specific surface area occurs in the grinding interval from 10 min to 50 min, then the kinetics of increase in specific surface area becomes slower. It is found that instead of natural sands it is possible to apply screenings of concrete scrap. It is determined that natural sands and screenings of concrete scrap are characterized by good grindability. Grinding variables for sand and screenings of concrete scrap are identical. It is established that particle size distribution of finely ground cement systems varies upon dispergation, and content of finer particle sizes in total bulk of ground substance increases with increase in specific surface area, thus facilitating elimination of stresses in solidified cement stone. It is mentioned that upon increase in filling ratio of cement from 30% to 50% water requirement of finely ground cement mixtures increases. It is established that the use of preliminary regrinding of fillers and subsequent combined grinding of dry constituents makes it possible to obtain homogeneous fine cement mixture with preset particle size distribution. It is demonstrated that combined activation together with modifiers facilitates obtaining of required strength properties of colloidal cement composites, thus providing decorative coatings on the basis of colloidal cement materials.