Characterizing pore volume, sizes, and connectivity in pervious concretes for permeability prediction

Methods of characterizing the pore structure features in a cement-based material with open pore structure, called pervious concrete, and the use of these pore structure features in permeability prediction is the focus of this paper. Porosity of several pervious concrete mixtures is determined using volumetric and area fraction methods whereas stereology and mathematical morphology based methods are used to extract the characteristic pore sizes. The characteristic pore sizes determined using several methods relate well to each other. A Weibull probability distribution function is found to adequately model the pore size distribution in pervious concretes. The values of porosity and the morphologically determined pore sizes, along with the pore phase connectivity represented using an electrical conductivity ratio, are used in a Katz-Thompson type relationship to predict the permeability of pervious concretes. It is shown in this paper that maximization of water transport behavior of pervious concretes is best achieved by increasing the pore connectivity factor.