Improvement of strength characteristics of lateritic sub-grade soil with shredded polyethylene waste

Abstract

This paper presents the results of investigation of the behavior of pavement subgrade soil stabilized with shredded polyethylene waste. Shredded high density polyethylene High Density Polyethylene Waste of maximum size 20 × 25mm was used for the improvement of lateritic soil at various percentages which are; 1%, 2%, 3%, 4%, and 5% respectively. Series of laboratory tests such as, Compaction and California Bearing Ratio (CBR) were conducted to determine the influence of polyethylene waste on the lateritic soil. The results reveal that addition of polyethylene waste to the soil increased the optimum moisture content (OMC) but, reduced the maximum dry density (MDD) from 2338.60kg/m³ to 1941.64kg/m³. A decrease in the dry density of soil sample shows that low comparative energy would be required for the soil to attain its maximum dry density; as a result the cost of compaction is significantly reduced. Improvement in CBR values was also observed for laterite-polyethylene mixture; resulting in maximum CBR value of 13.18% under soaked condition. This value falls within the range of 10% to 25% CBR value specified for sub grade soils by the AASHTO standard and the Nigerian Highway Design Manual, Federal Ministry of Works and Housing. An increase in the California Bearing Ratio value can significantly reduce the total thickness of the pavement; hence, the total cost involved in the project. The strength of Lateritic clay subgrade soils can be improved with the addition of five percent (5%) Shredded high density polyethylene (HDPE) Waste of maximum size 20 × 25mm.

Keywords: Lateritic soil, High density polyethylene (HDPE) waste, Pavement thickness, Sub-grade soil