Soil stabilisation by waste materials has been recently employed to enhance soil engineering properties. The purpose of this study is to compare the impact of utilising sawdust in its raw form versus sawdust ash as a soil stabiliser. This is to determine if sawdust (SD) can be considered as a substitute for sawdust ash (SDA) in order to reduce incineration and air pollution. To fulfil this aim, the Atterberg limits, modified Proctor test, and Direct Shear test were performed on both stabilised and non-stabilised mixtures of clayey soil. The soil was treated with 2%, 5%, 8%, 12%, 15%, and 20% by soil dry weight of both SD and SDA. The findings show that the use of SD and SDA leads to a reduction in the plasticity index and the maximum dry unit weight of the soil while increasing its optimum moisture content. The bearing capacity of the soil was greatest at 5% for both SD and SDA, with SD exhibiting a greater enhancement (31.89%) than SDA. Therefore, it is recommended to utilise SD instead of SDA for soil stabilisation due to its superior effectiveness and less harmful environmental impact.
Keywords: Sawdust; bearing capacity; compaction; sawdust ash; soil plasticity.