Durability of Reinforced Concrete Members Considering the Dynamic Interaction of Stress-Corrosion Expansion and Cracking

Abstract

In order to study the whole process of corrosion expansion and cracking of protective coatings of reinforced concrete columns under the coupling condition of load and chloride corrosion environment, the transmission characteristics of chloride salts in loaded concrete columns and the deterioration mechanism of cracking and spalling of protective coatings caused by steel corrosion are studied. The transport characteristics of chloride salts in concrete under the coupling condition of load and erosion environment are studied by means of creep tester. The loadbearing levels of specimens are divided into four groups according to the design values of ultimate load: 0%, 20%, 40% and 60%. The transport of chloride ions in concrete in marine environment is simulated by dry-wet cycling method. The results show that the existence of compressive stress accelerates the chloride ion transport in concrete at the initial stage of loading, and the higher the stress level, the faster the chloride ion transport. With the increase of loading time, the stress hinders the transport process of chloride ion. In the same period, the transmission efficiency in concrete without stress is the highest. In the same period, the chloride ion concentration on the surface gradually decreases with the compressive stress level. The longer the time, the more obvious the downward trend. The peak chloride ion content has little change with the increase of the compressive stress level; at the same compressive stress level, the chloride ion diffusion coefficient is basically unchanged with the increase of the dry-wet cycle; in the same cycle, the chloride ion diffusion coefficient increases with the increase of the stress level, but does not show a linear relationship. Using large-scale finite element DIANA (High-end Nonlinear Finite Element Analysis Software), the whole process of rust expansion and cracking of protective layer of loaded concrete column is numerically analyzed.