Savchuk V. Soil-containing materials modified by industrial wastes with increased electrical resistance for railway structures

Thesis for the degree of candidate of technical sciences in specialty 05.23.05 - building materials and products. – Ukrainian State University of Railway Transport, Ministry of Education and Science of Ukraine, Kharkov, 2018. The thesis deals with development of a soil-containing building material with a higher electric resistance and adequate physical and mechanical properties on the basis of soil, industrial slag and activated sludge for foundations of railway facilities in order to prevent leakage and stray currents causing electrocorrosion damages in their structures. The theoretical concepts of the structural formation of a composite material based on soils, industrial slags and activated sludge from biological treatment stations were extended. It has properties of an ionoheneous surface-active material and forms electro heterogeneous contacts with hydrated products of slags and soil particles. The possibility to use activated sludge from biological treatment stations as a solidifying activator for acid and basic slags due to amphoteric character of functional groups of the organic component of activated sludge was grounded. The theoretical models of change in electric properties of multicomponent systems, and soil-containing materials are among them, were carefully studied. These changes are the result of interactions of functional groups of the organic component of activated sludge with ions of a pore solution; it decreases their mobility and worsens ionic conductivity of the material as a whole. A composite material with a higher electric resistance based on soil, metal slags and activated sludge from biological treatment stations was developed. Results of the research were introduced to protect buildings and structures from electrocorrosion caused by leakage and stray currents; they were also adopted in the academic curricula.