MOISTURE INFLUENTIAL DEPTH IN CONCRETE: CONCEPT AND MODELLING
The transport of external agents as chloride into concrete is intimately linked tomoisture (water) movement. Drying-wetting cycles are identified as the most favorableconditions for chloride penetration and the subsequent steel corrosion processes. Under suchcycles,chloride ions migrate into concrete material by both mechanisms of convection anddiffusion. The depth of convection zone of chloride transport can be measured by moistureinfluential depth in concrete. In the present paper,the moisture transports during drying andwetting are modeled respectively by diffusion and absorption processes. An analyticalapproach is adopted to investigate the influential depth. To help the analysis,the concept ofequilibrium time ratio is proposed for drying-wetting cycles by the balance between waterloss and intake. Measured by this time ratio,drying-wetting cycles are classified into drying-dominated,wetting-dominated and equilibrium ones. The corresponding moisture influentialdepths are expressed explicitly in terms of environmental factors and material transportproperties. With the available concrete sorptivity data,the equilibrium time ratio andinfluential depth are calculated and discussed in depth.
concrete chloride drying-wetting cycles influential depth service life
Kefei LI Chunqiu LI Zhaoyuan CHEN
Key Laboratory of Structural Engineering and Vibration of China Education Ministry,Civil Engineering Department,Tsinghua University,Beiiing,PR China
国际会议
The International Conference on Durability of Concrete Structures(2008年混凝土结构耐久性国际学术会议)
杭州
英文
473-479
2008-11-01（万方平台首次上网日期，不代表论文的发表时间）