INFLUENCE OF MECHANOMAGNETIC ACTIVATION OF SOLUTIONS CaCl2 AND Na2S2O3 ON PHASE STRUCTURE OF CEMENT STONE

Abstract

The mechanism of the joint influence of the magnetic field and hydrodynamic cavitation on the properties of CaCl2 and Na2S2O3 solutions used for mixing cement pastes is considered. Hydrodynamic cavitation leads to the formation of reactive oxygen forms, HCO3– anions, carbon dioxide nanobubbles, and initiates the interaction of new forms with impurity metal cations dissolved in water. After mechanomagnetic treatment of the solutions, particles of a solid phase with sizes of 5...10 and 10...100 nm were found in them. The observed increase in the ξ- potential indicates the stabilization of such dispersed systems with the preservation of nanoscale fractions in them (up to 3 days). At the same time, the progress of reactions under the conditions of tightness that occur after cement paste has been mixed. The effect of activating factors in tap water is more pronounced than in distilled water, which is explained by the process of hydration of the carbonate ion and the formation of fine nucleation centers. Using X-ray phase analysis, it was found that, along with calcite, aragonite crystallizes in the resulting cement stone, which is practically absent in the control sample. In addition, the analysis of diffraction patterns taken on the modified samples reveals the inclusion of a carbonate ion. Obviously, optimization of the pore space in the cement stone is achieved both by clogging the pores with fine calcium carbonate, and by forming small pores during crystallization of ettringite-like phases. It is established that the resulting cement stone is characterized by increased strength (by 9-30%) and frost resistance (up to 55%) compared to that obtained by the traditional method.