Effect of reinforcement on the durability of bent reinforced concrete structures under conditions of alternating freezing and thawing

The article studies the influence of the level and type of reinforcement of bending elements of reinforced concrete structures on their bearing capacity under the influence of alternating freezing and thawing. Strength and deformation characteristics for B30 concrete class were taken according to Construction Rules SP 63.13330.2018, and after exposure to alternating freezing and thawing according to Construction Rules SP 52.105.2009. The study of the stress-strain state and the assessment of the bearing capacity were carried out according to a specially developed program, in which the diagrammatic method was implemented. It is shown that the durability of bent reinforced concrete structures depends on the percentage and type of reinforcement. When reinforcing with longitudinal tensile reinforcement equal to 1%, the decrease in the bearing capacity of a reinforced concrete beam after exposure to alternating freezing and thawing will make up 5.5%, and in case of 2.5% reinforcement it will equal to 20.9%. In addition, the nature of fracture will change and the stress in the tensile reinforcement will not reach the design resistance. If it is impossible to limit the percentage of reinforcement of longitudinal tensile reinforcement, it is recommended to use double reinforcement. Installation of working reinforcement in a compressed zone in a volume of 50% of the stretched one with a reinforcement percentage of 2% will reduce the decrease in bearing capacity to 2.2% after exposure to freezing and thawing cycles and not change the nature of destruction.