Plugin O. Influence of the direct current on a concrete of flooded constructions and buildings, located nearby the electrified railway tracks

The thesis is devoted to experimentally theoretical research of influence of pulsating unidirectional leakage direct current of different voltage on an electro-corrosion of concrete of different strength and on a mortar of a concrete, reinforced-concrete and stone constructions located nearby the electrified by a direct current railway sections. It is established that the wear of buildings and constructions on a railway sections, electrified by a direct current, considerably higher, than on sections, electrified by an alternating current or non-electrified. Researches of sizes of potentials on rails, on a surface of ground and constructions of buildings at passing of trains with electric traction, and also at their absence were realized. Established, that these potentials appear synchronously with passing of trains with electric traction, their sizes and, consequently, damage degree of building structures and constructions, depend on their distance to the nearest electrified track, state of coverage and soil between them, state of foundation under rails, presences of basements and earthed equipment. As a result of a long-term exploitation a surface of a soil near a railway sections, in particular, on an embankment and at its foundation, is polarized near rails is a positive potential, at a foundation of embankment - negative. The mechanism of this polarization is disclosed. The long-term experimental researches of influence of the pulsating unidirectional direct electric field of different voltage on concretes of different composition and strength with the help of an original method and equipment were done. Theoretical notions of dissolution mechanism of a portlandite under the action of this electric field are developed. In accordance with that mechanism the investigated electric field is caused by a simultaneous dissolution all of portlandite blocks, so that the total duration of dissolution approximately equals the duration of a dissolution of a one block. The equation for the dissolution rate of the portlandite in a cement stone is deduced. Physico-chemical researches of concretes of different compositions confirmed the correctness of the theoretical notions of a mechanism of electro-corrosion of concrete. And also they proved that a concrete of an optimum composition has a high electro-corrosion resistance. Complex methods of protection of concrete, reinforced-concrete and stone constructions from an electro-corrosion are developed and applied.