Abstract. The diversity of active mineral admixtures of different origin, mineral composition, dispersion and activity, including by-products in many industrial processes necessitates investigating their properties and characteristics of interaction with gypsum cement compositions. Completed research allowed to define the hydraulic activity of the investigated mineral admixtures and their effect on the rheological and mechanical properties of the composite binder, as well as to determine their optimal content in the mixture. It was shown that the use of the tested active mineral admixtures in optimal amounts allows to obtain stable gypsum cement-pozzolanic system and improve the performance properties of products based on them, resulting in increase of the tensile strength in bending from 2 to 48%, at a compression -from 4 to 49% and can significantly extend the range of use them in the manufacture of a broad spectrum of building products.

The paper shows the effectiveness of the use of a polyfunctional complex modifier for a gypsum-cement-pozzolanic binder (GCPB), which allows reducing the water requirement of the mixture by 35%, increasing the flexural strength of gypsum-cement-pozzolanic composites (GPPC) by 28%, and 25% for compression. The results of experimental studies of the effect of polypropylene fibers on the basic physicomechanical properties of a central processing center are presented. The performed studies have shown high efficiency of polypropylene fibers of the type VSM-II-6 for dispersed reinforcement of the central industrial park. The maximum increases in the values of the flexural strength (by 41.2%) and compression (by 20%) are achieved with their volume content in the amount of 1%. It should be noted that the introduction of the studied fibers with a length of more than 6 mm did not lead to the expected result, which is due to the formation of a heterogeneous structure of the GPPC

Gypsum and gypsum-cement-pozzolanic composites are of significant interest as materials and products for building decoration. The current tendency to reduce the consumption of gypsum-based materials and products in the context of growth and development of the finishing materials market depends on the decrease in their competitiveness compared to peers. This leads to significant interest in improving the quality of products based on gypsum and gypsum-cement-pozzolanic binder. Dispersed reinforcement is one of the ways of improving performance characteristics. The role of the type of reinforcing fibers in the formation of the gypsum-cement-pozzolanic composites structure and properties is studied in article. The influence relations of the cellulose fibers content with varying grinding degrees on the relative flexural and compressive strength of a gypsum-cement-pozzolanic matrix are obtained. It was found that the optimal content of cellulose fibers in the modified gypsum-cement-pozzolanic matrix is 0.5-1% by weight of the binder, the best indicators of flexural and compressive strength are achieved by grinding cellulose fibers to 30°SR. Using scanning electron microscopy, it was found that the microstructure of a disperse-reinforced gypsum-cementpozzolanic matrix is characterized by a uniform cellulose fibers distribution, the predominance of directionally frame reinforcement with a fibers linear orientation in the sheet plane. In this way the right choice of the type, crushing degree and cellulose fibers content can improve the quality and expand the application area of the produced gypsum-cementpozzolanic composites.

There are a lot of different methods of cold weather concreting. One of the weakly efficient methods of artificial concrete heating is electrode heating. The effectiveness of electrode concrete heating can be improved by means of conductive mineral addition to concrete mix that helps to support optimized resistivity of structure, reduce power costs and the period of development of strength in concrete. It is found that contraction of concrete mix modified by floured shungite in the quantity of 1% by mass of cement (5.18 ml) is lower than contraction of the initial unmodified concrete mix (8.15 ml) which shows its hydration processes slowing and demonstrates noneffect of shungite on concrete strength increase during electrode concrete heating. Concrete mix modifying by floured shungite helps to increase concrete temperature compared to initial mix by the value up to 8°C during the period of 0-20 hours of electrode heating, which leads to the structure’s strength development rate increase. Electric resistance decrease of the modified concrete mix that is observable during this process shows us improvement of the effectiveness of electrode concrete heating with shungite.

Abstract. The authors investigated the influence of modifying agents, based on the realization of three-factor plan of the second-order, on physico-mechanical properties and durability of fiber cement boards based on cellulose fibers.