The Wall Effect Of Elliptical Particle Distribution And Prediction Of The Chloride Diffusivity Of Concrete

With the continuous development of computer techniques, the studyon the quantitative relationship between the macroscopic physicalproperties and mesostructure of concrete by numerical modeling methodshas become an important topic. The macroscopic physical properties ofconcrete are dependent on its mesostructure, such as the aggregate sizedistribution, aggregate shape, and interfacial transition zone (ITZ), whichare all the important parameters for the optimal design of concretematerials. The chloride diffusivity of concrete is particularly important tothe durability assessment and design of concrete structures and materials.The determination of the chloride diffusivity of concrete is a challengingtopic from theory to practice.The intention of this thesis is to study the wall effect of ellipticalparticle distribution and to predict the chloride diffusivity of concrete. For agiven area fraction and aspect ratio, the wall effect of elliptical particle distribution is simulated. For aggregate particles, the effects of themaximum aggregate diameter and aspect ratio on the thickness of theboundary layer are evaluated in a quantitative manner. For cement particles,the ITZ thickness is expressed as a function of the maximum cementdiameter and water/cement ratio. A prediction method is presented for thechloride diffusivity of concrete with inhomogeneous ITZ. The validity ofthe method is verified with experimental results obtained from the literature.The effects of the aggregate gradation, maximum aggregate diameter, andITZ thickness on the chloride diffusivity of concrete are analyzed.