ABSTRACT

The theoretical framework for the description and analysis of fluid transport processes in concretes developed in Chapter 2 uses a macroscale approach to describe liquid flow in terms of potentials which can be defined and measured without reference to the microstructure. Without deviating from this method of analysis it is useful to consider aspects of the microstructure of concrete that deserve attention when assessing their liquid barrier performance. In this chapter we consider the effects of the coarse aggre­ gates on liquid movement in concretes. We also present a general analysis to describe the movement of liquids through a concrete consisting of a series of discrete layers. Finally we consider the influence of moisture content and porosity on the diffusion of organic vapours through concrete.