Document Type : Research Paper


1 Civil Engineering Dept., University of Technology-Iraq, Alsina’a street, 10066 Baghdad, Iraq.

2 Civil Engineering department- university of technology, Baghdad, Iraq.

3 Civil Engineering Department ,University of Technology, Baghdad, Iraq


This paper investigates the impact of the plant fly ash (dry tree leaves) addition on the geotechnical properties of the landfill soil, where an engineering laboratory landfill simulating a real landfill was manufactured. Two percentages of plant fly ash (10% and 15%) were used to reduce or prevent the penetration of heavy metals resulting from the decomposition of landfill waste into the soil and conducting laboratory tests such as the Atterberg test, specific gravity test, compaction test, permeability test, SEM test, and heavy metals analysis. The results of laboratory tests indicate a decrease in the plastic limit and the liquid limit with the addition of plant fly ash, as well as a decrease in the specific gravity and a decrease in dry unit weight with an increase in the need for water content when adding plant fly ash. In contrast, the permeability increased with the addition of plant fly ash. In the most important laboratory test, which is the chemical analysis of soil metals, the soil improved with plant fly ash gave results indicating a lower level of metals pollution at depths of (10 cm, 20 cm, and 30 cm) of soil layer compared to natural soil. The analysis was conducted on 7 basic pollutants (cadmium, copper, iron, Manganese, Zinc, Chromium, and lead), where the percentage of pollutants decreased in improved soil compared to natural soil under the same conditions by (50%, 74%, 62%, 68%, 60%, 68%, and 55%) respectively.

Graphical Abstract


  • Using the addition of plant fly ash (dry tree leaves) on the geotechnical properties of the landfill soil.
  • Two percentages of plant fly ash (10% and 15%) were used.
  •  The soil improved with plant fly ash gave results indicating a lower level of heavy metal pollution.
  • The results indicated a decrease in the plastic and liquid limits with the addition of plant fly ash, and a decrease in the specific gravity and dry unit weight.


Main Subjects

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