Skip to main content

Microstructural effects of environmental salinity on unbound granular road pavement material upon drying


Areas of high environmental salinity are predicted to increase over the next 40 years in Australia, due to land use and climatic changes. This presents a risk to road assets as accumulation of salts within roads has been found to cause damage to thin bituminous surfacings. It is in this context that the present study explores the microstructural changes caused by environmental salt crystals accumulating within unbound granular road pavements. Fine-grained specimens were prepared by static compaction, immersed in different solutions, and finally either freeze-dried or oven-dried at 40 °C. The effects of different drying procedures and salinity on soil’s microstructure were explored via mercury intrusion porosimetry and scanning electron microscope observation. Results suggest that a freeze-drying process can significantly modify the microstructure, which should be taken into account when conducting any microstructural analysis on high-salinity soil specimens.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4


  1. Al-Rawas A, Goosen M (2006) Expansive soils: recent advances in characterization and treatment. Taylor & Francis, London

    Book  Google Scholar 

  2. Angeli M, Benavente D, Bigas J-P et al (2007) Modification of the porous network by salt crystallization in experimentally weathered sedimentary stones. Mater Struct 41:1091–1108. doi:10.1617/s11527-007-9308-z

    Article  Google Scholar 

  3. Casini F, Vaunat J, Romero E, Desideri A (2012) Consequences on water retention properties of double-porosity features in a compacted silt. Acta Geotech 7:139–150. doi:10.1007/s11440-012-0159-6

    Article  Google Scholar 

  4. Cuisinier O, Laloui L (2004) Fabric evolution during hydromechanical loading of a compacted silt. Int J Numer Anal Methods Geomech 28:483–499. doi:10.1002/nag.348

    Article  Google Scholar 

  5. de Carteret R, Buzzi O, Fityus S (2010) A review of the effects of salinity on road pavements and bituminous surfacings. In: ARRB conference 24th, pp 1–16

  6. de Carteret R, Buzzi O, Fityus S, Liu X (2013) Effect of naturally occurring salts on tensile and shear strength of sealed granular road pavements. J Mater Civ Eng. doi:10.1061/(ASCE)MT.1943-5533.0000938

    Google Scholar 

  7. Delage P, Pellerin F (1984) Influence de la lyophilisation sur la structure d’une argile sensible du Québec. Clay Miner 19(2):151–160

    Article  Google Scholar 

  8. Delage P, Marcial D, Cui Y, Ruiz X (2006) Ageing effects in a compacted bentonite: a microstructure approach. Géotechnique 56:291–304. doi:10.1680/geot.2006.56.5.291

    Article  Google Scholar 

  9. Hillel D (1998) Environmental soil physics: fundamentals, applications, and environmental considerations. Elsevier Science, Amsterdam, p 160

    Google Scholar 

  10. Koliji A, Laloui L, Cusinier O, Vulliet L (2006) Suction induced effects on the fabric of a structured soil. Transp Porous Media 64:261–278. doi:10.1007/s11242-005-3656-3

    Article  Google Scholar 

  11. Musso G, Romero E, Della Vecchia G (2013) Double-structure effects on the chemo-hydro-mechanical behaviour of a compacted active clay. Géotechnique 63:206–220. doi:10.1680/geot.SIP13.P.011

    Article  Google Scholar 

  12. Obika B (2001) The prevention and repair of salt damage to roads and runways. Botswana Roads Department Guideline, pp 1–24

  13. Obika B, Freer-Hewish RJ, Newill D (1992) Physico-chemical aspects of soluble salt damage of thin bituminous surfacing. In: International conference on the implications of ground chemistry and microbiology for construction

  14. Obika B, Freer-Hewish RJ, Woodbridge M, Newill D (1995) Prevention of salt damage to thin bituminous surfacings: design guidelines. In: Sixth international conference low volume roads. Minneapolis, MN, pp 3–12

  15. Perrott KW (1977) Freeze-drying of soil clays. Geoderma 17:219–224. doi:10.1016/0016-7061(77)90052-0

    Article  Google Scholar 

  16. Romero E, Simms PH (2009) Microstructure investigation in unsaturated soils: a review with special attention to contribution of mercury intrusion porosimetry and environmental scanning electron microscopy. In: Laboratory and field testing of unsaturated soils. Springer, Berlin, pp 93–115

  17. Shackelford CD, Benson CH, Katsumi T et al (2000) Evaluating the hydraulic conductivity of GCLs permeated with non-standard liquids. Geotext Geomembr 18:133–161. doi:10.1016/S0266-1144(99)00024-2

    Article  Google Scholar 

Download references


This work was sponsored by Austroads and the Roads and Maritime Services, NSW. Their financial support is gratefully acknowledged. Staff of the University of Newcastle’s Electron Microscope and X-Ray Unit are also acknowledged for their help and advice in using the XL30 SEM and Oxford EDS, and Dr. Brett Turner for conducting the IC analysis.

Author information

Authors and Affiliations


Corresponding author

Correspondence to O. P. Buzzi.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Liu, X.F., de Carteret, R., Buzzi, O.P. et al. Microstructural effects of environmental salinity on unbound granular road pavement material upon drying. Acta Geotech. 11, 445–451 (2016).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Microstructure
  • MIP
  • Road pavement
  • Salinity
  • Salt crystallization
  • SEM