Effect of artificial aggregate shapes on the porosity, tortuosity and permeability of their packings

• Published in: Powder technology 2022-01, Vol.397, p.117019, Article 117019
• Main Authors: Conzelmann, N.A., Partl, M.N., Clemens, F.J., Müller, C.R., Poulikakos, L.D.
• Format: Article
• Language: English
• Subjects: Aggregate shape; Aggregates; Artificial aggregates; Construction materials; Energy harvesting; Gravel; Non-convex shapes; Packing; Permeability; Porosity; Tortuosity
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2021.11.063

Natural aggregates such as gravel are used in many construction applications for which porous structures are needed, for example to allow water drainage. However, the range of attainable porosities is limited due to the irregular shapes of natural aggregates. Here we investigate artificial aggregates of engineered shapes, which allow structures with porosities exceeding 0.7. In this study packings of a variety of artificial aggregate shapes are examined by both numerical and experimental techniques. We can establish a correlation between the porosity of a packing and the sphericity of the aggregates. Furthermore, we confirm that the Carman-Kozeny correlation can be used to predict accurately the permeability of a packing for a wide range of porosities (0.33–0.78). Establishment of this basic relationship between the porosity and permeability of a packing is critical for the design of artificial aggregates for novel applications such as energy harvesting from pavements. [Display omitted] •Low sphericity non-convex aggregates form highly porous packings.•Tortuosity has negligible influence on permeability.•Simple correlation between packing porosity and permeability established.•Carman-Kozeny equation holds for highly-porous, highly non-spherical packings.