Sand-attapulgite clay mixtures as a landfill liner

Amer A. Al-Rawas*, Yahia E.A. Mohamedzein, Abdulaziz S. Al-Shabibi, Salem Al-Katheiri

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


This paper investigates the potential use of sand-attapulgite (palygorskite) mixtures as a landfill liner. The sand and attapulgite clay used in this study were brought from Wahiba (eastern Oman) and Al-Shuwamiyah (southern Oman), respectively. Initially the basic properties of the sand and clay were determined. Then the attapulgite clay was added to the sand at 5, 10, 20 and 30% by dry weight of the sand. The sand-attapulgite clay mixtures were subjected to mineralogical, chemical, microfabric and geotechnical analyses. The X-ray diffraction (XRD) qualitative analysis showed that attapulgite is the major clay mineral. The chemical compounds, exchangeable cations and cation exchange capacity (CEC) for the samples were determined. The CEC for the sand-clay mixtures is low but increases with the increase in clay content. The scanning electron microscope (SEM) examination showed that the addition of clay developed coating between and around the sand grains which results in filling the voids and reducing the hydraulic conductivity of the sand-clay mixtures. The hydraulic conductivity values for the pure clay and sand + 30% clay mixture prepared at 2% above optimum water content are slightly higher than hydraulic conductivity requirements for landfill liners but can be acceptable. The geotechnical study which included grain size distribution, Atterberg limits, specific gravity, compaction, hydraulic conductivity and shear strength tests showed that the sand+30% clay mixture prepared at 2% above optimum water content can be considered to satisfy the requirements for landfill liners. For all sand-clay mixtures no swelling was recorded and the addition of clay to the sand improved the shear strength.

Original languageEnglish
Pages (from-to)1365-1383
Number of pages19
JournalGeotechnical and Geological Engineering
Issue number5
Publication statusPublished - Oct 2006


  • Attapulgite
  • Hydraulic conductivity
  • Landfill liners
  • Shear strength
  • Swelling

ASJC Scopus subject areas

  • Architecture
  • Geotechnical Engineering and Engineering Geology
  • Soil Science
  • Geology


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