The effect of dispersed reinforcement on the macro- and microstructure of dry building mixes using activation

Introduction. Dry building mixes based on hydraulic binders are currently widely used. The use of dry mixes is multifaceted and is mainly associated with the preparation of solutions and fine-grained concrete. These mixes are obtained by regulating rheological and physical-mechanical properties by introducing modifying additives and microfillers in the form of glass microspheres.

Materials and methods. Polymer and basalt fibre were used to regulate the properties of the mix at the microscopic level, thereby creating a strengthened reinforced microstructure of hardened fine-grained concrete. The compositions of dry mixes based on polymer and basalt fibre were selected using a superplasticizer and 10 % coated hollow glass microspheres
of the MS-VP-A9 brand. A dry mix based on the specified composition with the use of superplasticizers, glass microsphe-res, and basalt or polymer fibre is prepared by mixing and grinding in a linear induction rotator, which has an alternating field inductance of 0.2 T and a frequency of 50 Hz. The mixture is processed for 240 seconds. Polymer and basalt fibres were introduced into the dry mix separately, i.e. only one of the two presented types of fibres was used in each composition.

Results. Dry mixes activated in an electromagnetic field were mixed with water in the amount necessary to obtain solutions of equal mobility. The solution was prepared for 4–5 minutes, while the resulting mixtures had increased plasticity and homogeneity with an equal amount of mixing water, in comparison with the control compositions, without the use of basalt or polymer fibres.

Conclusions. The influence of the type and quantity of fibre on the physical and mechanical properties of fine-grained concrete obtained on the basis of dry building mixtures activated by electromagnetic treatment was determined.

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