Assessing the influence of ITZ on the steady - state chloride diffusivity of 1 concrete using a numerical model

a Faculty of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou 310014, PR 5 China 6 b Concrete Durability Group, Department of Civil and Environmental Engineering, Imperial College London, 7 SW7 2AZ, UK 8 9 ABSTRACT 10 11 In this study, the influence of the aggregate-cement paste interfacial transition zone (ITZ) on the steady-state 12 chloride diffusivity of mortars and concretes was examined using a semi-empirical, three-phase composite 13 sphere model. Mortars and concretes were modelled as three-phase composites consisting of the aggregate, bulk 14 cement paste and an inhomogeneous ITZ. The latter was divided into a series of homogenous concentric shell 15 elements of equal thickness. The initial porosity and cement gradients at the ITZ were first estimated from the 16 overall water/cement ratio ( c w / 0 ). The evolution of the porosity, solid hydration products and remnants of 17