Research of the causes of premium destruction of reinforced concrete elements of bridges and pipelines when using chlorine anti-ice materials

Abstract

Factors affecting the speed and volume of destruction of reinforced concrete elements of man-made structures are analyzed. The main causes of damage to bridges include corrosion of concrete and reinforcement due to water ingress from the roadway in the autumn-winter period, as it contains chemicals that are used to combat winter slippage and cause corrosion in addition to carbonization. First, the surface layer of concrete is saturated with salt. During repeated treatments with anti-icing materials, the solution penetrates deeper and deeper into the thickness of the concrete due to capillary absorption. According to the research results, it can be concluded that the most dangerous concentration is 5 % concentration of NaCl. Under the action of the indicated anti-icing material, a steady decrease in compressive strength is observed up to 45 cycles, and then the curve stabilizes. The resistance of cement concrete to the aggressive action of anti-icing materials is unstable. There are periods when the structure of concrete is sufficiently stable and periods in which its stability can significantly decrease. During the operation of such concrete, there is a danger of irreversible loss of strength due to the simultaneous action of anti-icing materials on the concrete, sign-changing temperatures and intense dynamic mechanical loads from the movement of vehicles. The generalization of research results indicates the possibility of increasing the corrosion resistance of concrete by applying a protective layer on its surface, which ensures the formation of a hydrophobic film and prevents the penetration of aggressive solutions into concrete. The impregnating composition penetrates shallowly, but to a sufficient depth to primarily contribute to increased strength. But, as a result of the effect of sign-changing temperatures, microdefects continue to accumulate inside the concrete structure, which ultimately lead to a decrease in its strength.