Wastes from the production of heat-insulating basalt wool as an additive in cement-based materials

Abstract

The building materials science at the present stage is aimed at expanding the components of composites. At the same time, these components acquire special value with the simultaneous disposal of various wastes. One of such materials that have not been studied before are molten spherical basalt particles (beads) formed as waste in the production of heat-insulating materials. The aim of the article was to study the effect of balls on the structure formation of cement materials. The vibration spectra of basalt balls, which differ from the spectra of pure silica, were studied, which makes it possible to form silicates with different contents of aluminum and iron. The revealed features of the particle surface morphology, grain composition and the presence of amorphous silicate phases in this material confirm its effective use as an active mineral additive in cement concretes of normal and autoclaved hardening. The activity of this binder component is confirmed by the fact that after 180 min 15 mg/g calcium hydroxide is absorbed. SEM images confirmed compaction of the microstructure of cement composites containing crushed basalt granules. As a result of the use of this new additive, the compressive strength increases, while the maximum effect is achieved when 5–10% of finely ground basalt balls are introduced into the mixture. Amorphous quartz accelerates the pozzolanic reaction, increasing the packing density of hydration products. These basalt granules are able to accumulate water, which then takes part in the hydration reaction in a dosed manner. The increased water-holding capacity of the created binder creates conditions for the consistent growth of hydrated products and for synthesis with minimal internal stresses and volumetric deformations.