Framework to characterize nonlinear flow through pervious concrete

Abstract

Pervious concretes have been increasingly used since they allow for better water flow. Flow through pervious concrete is usually assessed with Darcy's law, which presupposes linearity between flow rate and hydraulic gradient. However, some researchers reported this does not always hold, especially at faster flows. In such cases, Forchheimer's law may be used. In this paper, criteria for delimiting flow regimes was applied to evaluate hydraulic behavior. Forty-two specimens had their porosities measured and were tested in a constant head permeameter. Although low to moderate hydraulic gradients were applied, resulting flows already showed to be non-Darcian. A dimensionless permeability parameter engendered by the mentioned approach was able to adequately and unequivocally grade the flow resistance offered by each specimen. Correlations between this parameter and porosity were obtained and bestowed rich interpretations of how heterogeneity in pervious concretes impacts flow behavior. This may be key for designing better pervious concretes.