Stabilization of Lateritic Soil Using PET Bottle Shreds and Periwinkle Shell Ash for Subgrade Layer of Road Pavement

Abstract This study investigates the stabilization of lateritic soil with polyethylene terephthalate bottle shreds and periwinkle shell ash for use in the subgrade of road pavements. The main aim is to enhance the engineering properties of lateritic soil to make them suitable for use as a road construction material. The lateritic soil used for this research work was obtained from Iju, Ota, Ogun state, while other materials were PET bottle shreds and periwinkle shell ash. The experimental Laboratory tests in this project are moisture content, specific gravity determination, particle size distribution, Atterberg limits, permeability, unconfined compressive strength, compaction test, and California bearing ratio test. Results show that adding 6% PET bottle shreds optimizes the soil's unconfined compressive strength (UCS) and improves it considerably in compressive strength. Further stabilization with varying percentages of periwinkle shell ash, 2%, 4%, 6%, 8%, and 10%, shows that the mix of 6% PET bottle shreds and 6% periwinkle shell ash produces a CBR value of 19.5%, while the natural soil had a CBR value of 5.5%. Other improvement parameters from this combination also prompted the best suitability for subgrade applications through its permeability and compaction characteristics. This study therefore concludes that the use of PET bottle shreds and periwinkle shell ash as stabilizers can eventually improve the mechanical properties of lateritic soil to a great extent, hence providing a sustainable solution in road pavement construction.