外文資料翻譯--溫度和相對(duì)濕度對(duì)沿印度海岸的鋼筋混凝土構(gòu)件腐蝕起始時(shí)間的影響-wenkub
2023-05-19 04:35:07 本頁(yè)面
【正文】 de concentration and variable diffusion coefficient is used. Corrosion is initiated when the chloride concentration on steel reinforcement exceeds a threshold value. The various input parameters considered in the model are surface chloride concentration (Cs), chloride threshold value (Cth), Concrete cover (X), reference diffusion coefficient (Dref ), age (t), reference age (tref ), diffusion decay index (m) and monthly temperature and relative humidity correction factors f(T) and f(h) respectively。 diffusion。 sensitivity. 1. Introduction Reinforced concrete structures are most widely used across the world. Reinforced concrete (RC) structures deteriorate with time in a corrosive environment affecting aesthetic, functional and structural aspects in service. The rate of deterioration depends on factors such 5 as planning, design, construction, operation/use, and maintenance. Degradation of concrete is related to its durability aspect and to its corrosion of reinforcing steel. The corrosion of the steel reinforcement leads to concrete fracture through cracking, delamination and spalling of concrete cover, reduction of concrete and reinforcement cross sections, loss of bond between the steel reinforcement and concrete, and reduction in strength and ductility, which leads to irrecoverable losses and collapse of structures. Hence, the safety and serviceability of concrete structures in service needs to be considered. Carbonation, sulfate and chloride attack, and steel corrosion may cause the degradation of reinforced concrete members/buildings. The chlorideinduced (peration of chloride ions in to concrete) corrosion of the steel reinforcement is identified as one of the main cause of deterioration of different concrete structures (. bridges, offshore structures and parking garages). The sources of chlorides are the seawater, deicing salts, and air in marine environment. Reinforcement corrosion starts (in presence of moisture and oxygen) once the concentration of chloride ions at the reinforcing steel surface exceeds a threshold value (critical chloride content). Most corrosion initiation models are based on assumption of a Fickian process of diffusion for predicating the time and space variations of chloride content in concrete and on the concept of chloride threshold to define corrosion resistance of reinforcing steel to chloride attack. Therefore, the governing parameters of this diffusion based corrosion initiation model are
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