Introduction

1 Introduction

The ecological situation in our country and all over the world requires paying attention to the recycling of large-tonnage industrial waste. One of the ways of recycling is the use of waste as a secondary raw material in the construction industry [1-7]. In the cement industry, the waste of metallurgical production - granulated blast-furnace slag (GBFS) [8-9] is used as a raw material component and active mineral additive. It is known that products made of slag-based cements have a number of advantages over the plain Portland cement. These include: low exothermic reaction, increased corrosion and heat resistance, workability of concrete mix, protection of finished structures from weathering and cracking, - which generally increases the durability of structures [10-13]. Due to the slow set of strength at the initial time of hardening, this kind of cement was not widely used in civil engineering. To solve this problem, it was proposed to use hardening accelerators, complex additives, and superplasticizers in slag cements [14-17]. In work [17], electrolytes, in particular, the system of additives “Relaxol-Leader” based on the technogenic mixture of sodium thiocyanate and thiosulfate, which allows increasing the strength of slag Portland cement by 50 - 88%, were used as accelerators for hardening of slag Portland cement (SPC).

The authors of works [18-19] considered the preparation of cements and cement compositions with finely ground steel-smelting slags that, during combined hydration with cement, form hydration products in the form of submicrocrystalline hydrate phases that compact the structure of the cement stone and further bind the individual grains of the composition, which leads to the hardening of its structure.

Due to the fact that the scales of formation of blast-furnace slags are twice as high as the formation of steel-smelting slags, the present paper considers the use of GBFS as a finely dispersed component involved in the structure formation of the cement matrix.

The use of finely dispersed particles, including GBFS, in cement is accompanied with a number of problems, which include:

- difficulty of introducing them into the cement;

- uneven distribution in the volume of the binder;

- instability of the results of physical and mechanical tests of cement stone.

To solve these problems, studies were carried out to determine the optimal conditions for the introduction and distribution of finely ground GBFS (FGS) in the volume of the cement matrix, which contributes to the obtaining of stable characteristics of the cement stone.

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