Управління структурою цементного каменя з тонкомеленими мінеральними добавками

Abstract

Abstract.To select the volumes of additives-fillers introduced into cement that are optimal in terms of the quality and cost of the material obtained, it is necessary to know the mechanisms of their influence on the construction and technical properties of the material. The objects of the study were cement stones based on Portland cement clinker with a filler – fine ground quartz sand. Samples were tested for strength and investigated by drying thermograms to determine the specific surface of the solid phase. Based on the analysis of the results obtained, a mechanism is proposed for the influence of the filler on the properties of the cement stone, which consists in the formation, at a certain concentration of an additive of locally cluster structures in hardening cement paste. This leads to the emergence of special conditions in the microvolumes of hardening cement paste due to the interconnection of the filler grains with the coagulation-crystallization structure of cement hydration products growing on the active surface of the grains. As a result, significant changes in the structure of the formed cement stone with a higher specific surface should occur. In the framework of the proposed model, expressions are obtained for calculating the filler concentrations leading to the maximum strength properties of the material. These results allow to assign concentrations of fine ground filler, providing optimum physical and technical characteristics of concrete.