Analysis of water flow in an asphalt pavement surface layer with different thicknesses and different permeability coefficients

Abstract

The deleterious effect of water is a major factor that causes early degradation in hot mix asphalt (HMA) materials. The coefficient of permeability (k) is a parameter used to characterise HMA hydraulic transport properties. This study numerically evaluated the influence of the spatial distribution of k on the flow pattern within an asphalt surface layer with different thicknesses. Initially samples with different heights were prepared in the lab and cut in three parts and the air voids (AV) content and k values in each part were determined. From the experimental relationship between AV and k numerical simulations were conducted to characterise the transient flow inside an asphalt surface layer divided into sublayers in order to represent typical AV vertical distributions observed in the field. The results show that the heterogeneous distribution of k within the HMA layer could produce regions that are more susceptible to moisture damage due to the accumulation of water.

Keywords:

• asphalt mixture
• permeability
• water flow
• numerical simulation

Acknowledgements

The authors would like to express their thanks to the Brazilian National Council for Scientific and Technological Development (CNPq) for its financial support. The authors are also grateful to Insttale Engenharia Ltda. company, Petrobras and MFT for providing the materials used in this research. In addition, our thanks to, the Geotechnical Group of the Departamento de Engenharia Hidráulica e Ambienal - DEHA/UFC for providing the license to use the software.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPQ – Brazil [grant number 130155/2014-4].