Application of Plastic Waste (Polyethylene and Synthetic Polymers) as a Soil Modifier in Subgrades and Shallow Foundations

Polyethylene terephthalate (PET) is one of if not the most commonly consumed type of plastic in industry and they can be readily spotted as they are used for water, pop bottles, and a few types of packaging. Although alternative recycling solutions can help in the conservation of landfills, they are not a definite solution. In this study, as an alternative solution to the waste problem of PET products, been used to find an alternative solution to further enhance sand properties to make them suitable for construction zones. Despite other studies in this direction, none of them have reached the substantial results that this study has achieved. The reason being is the presence of a novel methodology that creates a remarkable interlocking strength between aggregates using plastics. This method which includes heating both sand and plastic particles up to the melting point of plastics has better effects on unconfined compression and shear strength of sand than plastic strips combined with sand in a solid form. The plastic waste percent used in this study were 2.5, 5, 7.5, and 10 percent of the dry weight of sand in 4 different sample preparation groups (SPM-1, SPM-2, SPM-3, and SPM-4). The results indicated up to 3745kPa compressive strength and 8.6 times improvement in shear strength of sand for SPM-3 in a melted plastic form.