RESEARCH OF BUILDING MATERIALS

REGULATION OF ELECTRICAL AND RHEOLOGICAL PROPERTIES OF HETEROGENEOUS SYSTEMS ON THE BASIS OF QUARTZ SAND AND GRAPHITE BY MECHANICAL ACTIVATION OF QUARTZ SAND

Vestnik MGSU 8/2016
  • Lopanov Aleksandr Nikolaevich - Belgorod StateTechnological University named after V.G. Shukhov (BSTU named after V.G. Shoukhov) Doctor of Technical Sciences, Professor, chair, Department of Health and Safety, Belgorod StateTechnological University named after V.G. Shukhov (BSTU named after V.G. Shoukhov), 46 Kostyukova str., Belgorod, 308012, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Fanina Evgeniya Aleksandrovna - Belgorod StateTechnological University named after V.G. Shukhov (BSTU named after V.G. Shoukhov) Candidate of Technical Sciences, Associate Professor, chair, Department of Health and Safety, Belgorod StateTechnological University named after V.G. Shukhov (BSTU named after V.G. Shoukhov), 46 Kostyukova str., Belgorod, 308012, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Guzeeva Oksana Nikolaevna - Belgorod StateTechnological University named after V.G. Shukhov (BSTU named after V.G. Shoukhov) postgraduate student, Department of Health and Safety, Belgorod StateTechnological University named after V.G. Shukhov (BSTU named after V.G. Shoukhov), 46 Kostyukova str., Belgorod, 308012, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 78-87

The authors present the experimental performance of the heat of wetting depending on the number of functional groups on the surface of quartz sand. It is established that in the process of increase of specific surface of fine ground quartz filler naturally there is an increase in the total number of active centers, but their number does not change per unit of surface. The calorimetric method of analysis established that the mechanical activation increases the reactivity centers. This is the result of chemical reactions occurring on the surface, for example, under the influence of water present in the air. The authors observed hydration of surface groups and change in their reactivity. A method of regulation of rheological characteristics of pastes with plasticizing additives in the system ”cement - quartz sand - graphite“ was developed, which was aimed to reduce the ultimate shear stress up to 0.5...1.3 PA and water-composite relationship of a sand mix by 15...25 % while maintaining the viscosity of the paste that provides a uniform application of the composite in screed floors technology possessing electrical conductivity. Polycarboxylate is an efficient plasticizing additive which maintains self-levelling effect of the mixture at optimum water-cement ratio. It was determined that the threshold concentration of electrical current flow in the studied system is 0.15 (wt.), at which the aggregation of contacting graphite particles with the formation of a continuous three-dimensional mesh a conducting current is observed in the structure of the composite. The change in the concentration of the graphite allows ensuring the stability of the electrophysical parameters of the resistive materials and structures based on them. In order to increase the electrical conductivity of graphite dispersions in a model system a plasticizer was added, which reduces water-composite ratio in the formation of pastes. Chemical-based plasticizer has no significant effect on the magnitude of the threshold concentration. The increase in activation time of silica sand leads to the increased resistance of the prototypes and to the reduction of specific electrical conductivity of graphite dispersions in the system under study from 9.8 Om-1·m-1to 0.018 Om-1·m-1. The optimum grind time is 2...5 minutes. Further grinding is impractical due to the deterioration of the electrical characteristics of the samples.

DOI: 10.22227/1997-0935.2016.8.78-87

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