ADVANCES OF ENVIRONMENT DAMAGE MECHANICS IN MARINE ENGINEERING CONCRETE

Safty and durability of marine engineering concrete structures are important concerns for mechanics researchers. Reinforced concrete is a composite of concrete matrix and reinforced steel bars. Steel bars could be corrosed due to attack by chloride ions in seawater. Also, microcracks’ nucleation and growth may occur in concrete matrix under the action of various chemical and physical factors. Such a corrosion damage leads to the increase of diffution coefficient of chloride ions in concrete and the accelerated corrosion of steel bars, and this eventually reduces the safety and durability of concrete. The damage of marine engineering concrete is induced by chemical factors and physical factors. Chemical factors include carbonization and attack of corrosive ions (such as chloride ions, sulfate ions, and magnesian ions), whereas physical factors include temperature, humidity, wave erosion, and ultraviolet radiation. In this paper, some advances on the research of damage mechanics in marine engineering concrete are inrtoduced. The mechanism of damage in concrete due to environment factors is firstly discussed, and then some theoretical models of damage mechanics are recommended, including the probability model of pit corrosion damage in steel bar, the evolution model of fracture toughness and cracks of concrete matrix under sulfate attack, wave erosion model of concrete structures, etc. Subsequently, the effect of corrosion damage on the diffusion of chloride ions is illustrated, and it is emphasized that the analysis on the diffusion of chloride ions may be uncorrect if the corrosion damage is not taken into account. Finally, some important problems needing to be solved in the future are presented.