Soil is exposed to pollution as oil in most countries around the world due to leakage or spillage of petroleum materials. Also, increase in vehicles and equipment usage due to the increase in life civilization causes large quantities of waste engine oil that are disposed into the surrounding soil. Previous study on sandy soil by carried out by the authors [1] indicated that . The optimum waste engine oil content is found to be 12% by dry wieght of sand. The present study, laboratory testing program was carriedd out to find the optimum value of waste engine oil that affects the geotechnical properties of clayey soils. On the other hand, waste oils contain different components that may interact soil particles, and change its geotechnical properties. The present study focused on the effect of wate engine oil contamination on the geotechnical properties of both sandy and clayey soils in terms of its engineering and mechanical properties. The clay samples are prepared using kaolin clay and were artificially contaminated by mixing with waste engine oil with ratios in the range of 0% to 20% by dry weight. The results of the non-contaminated kaolin were taken as references for comparison. The results indicated that waste engine oil reduces the optimum moisture content and increases the maximum dry density of the contaminated samples. Also, the relative density decreases with the increasing of waste engine oil content. On the other land, increase of waste engine oil content in the sandy soil has no effect on the angle of internal friction. The optimum percentage is found to be around 8% of waste engine oil content. Finally, a comparison is made between the results obtained for both sandy and clayey soils in terms of the optimum waste engine oil content.
 
 
Special Issue of AEIC 2024 (Civil Engineering  Session)