Features of the Formation of the Microstructure of Granular Aggregates on Different Binding Compositions

Abstract

This work includes a study of the microstructure of granular aggregates prepared on various binding compositions. The presented work includes three parts devoted to the analysis of the microstructures of granular aggregates taking into account the change in the percentage of the mineral filler in binding compositions. The article deals with the main aspects of the formation of the structure of granular aggregates during the hydration of Portland cement (PC 500-D0-N) and a binder composition (PC 500-D0-N + 10 % quartz sand) prepared in a vortex jet mill. The main regularities of the influence and dispersion of quartz mineral filler (fractions ≤0.16; ≤0.315; ≤0.63 mm) on structure formation during the hydration of binding components differing in the composition and particle dispersion are revealed. The paper analyzes physical and mechanical tests of the most promising samples with a study of their microstructure features. The study of the sample microstructures reveals the general regularities of the growth of crystalline phases of different densities. It is established that the introduction of 1 0% mineral fine-dispersed filler, in the form of quartz sand, contributes to the formation of sub-microcrystalline hydrate phases, which are centers of hydration, additionally binding individual grains of granular aggregates and compacting the structure of the overall system. In all samples, the formation of a block-rhythmic structure is observed, with the presence of individual block-aggregates. There is an overgrowth of microscopic pores with small crystalline neoplasms of calcium hydrosilicates. It is revealed that the structure of granular aggregates prepared on the basis of binder composition No. 1 (BK-1) has higher density than on Portland cement PC 500-D0-N.