Palant O. Concretes and products for tram tracks with high resistance to dynamic, electrical and temperature impacts

The dissertation considers the improvement of materials and parts of the tram track to reduce vibration, electrical impacts, temperature stresses in rails and crack formation in concrete. The specific features of arrangement and operation of the tramway lines were analyzed and disadvantages of conventional tram track structure were identified, including vibration and noise, electric corrosion damages, thermal rail stressing, crack formation in concrete rail seats, derailment of trams, etc. Theoretical and experimental studies were conducted which allowed to identify the influence of leakage currents and excess electric charges on the tram track structure; high vibration damping capacity of polyurethane is promoted by electrostatic repulsion between C=O functional groups with double bonds of the urethane groups, while high electrical resistance is facilitated by high electronegativity of these groups; in heavy concrete, substitution of crushed granite with quartz aggregate, and partial substitution of cement with quartz aggregate results in reduction of the linear temperature expansion coefficient of concrete; also, gluing of liners made of such concrete on the tram rail web reduces thermal stresses in the rails and decreases vibration velocity of the rail seat; and dependence of crack resistance of concrete under dynamic impacts from the coefficients of displacement of coarse and fine aggregate grains and water-cement ratio. The results of the study were implemented during the reconstruction of the tram lines in Kharkiv. The economic effect of UAH 2,317,000 is determined by a prolongation of the period between repairs during which the track is maintained in proper condition, etc.