Civil Engineering Department, University of Technology, 10066, Baghdad, Iraq



Soft clay soil is one of the problematic soil which is widespread in Iraq especially in middle and south of Iraq and has a low bearing capacity. This study investigates some of the mechanical properties of soft clay soil after adding the environmental waste material, egg shells. This study compares eggshell ash (ESA), eggshell powder (ESP), and limestone (L), which can be used as a stabilizer for soft clay while preserving natural limestone from consumption. ESP can be used as a replacement for limestone due to some similarities in chemical composition between it and limestone components. Soft clay soil brought from southern Iraq, which is used for this study and mixed with different percentages of ESA (2 - 6%), ESP (4 - 20%), and L (4 - 24%) by dry weight of soil. Lab tests such as specific gravity, Atterberg limits, compaction, and triaxial tests were used to evaluate the amendment samples and compare them with the reference one. The experimental results indicated that ESA increased the qualities of consistency, strength, and plasticity. It was found that the activity of the natural soil without any additives was decreased from 0.60 to 0.20 at 6% of ESA, while the activity dropped to 0.23 at 20% of ESP and 0.25 at 30% of L. Thus, it can be concluded that ESA was an effective stabilizer for improving the mechanical properties of soft soil samples.


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