Utilization of Post-Consumer Plastic Water Bottles as an Admixture for Improving the Soil Subgrade

Post-consumer plastic water bottles are foremost source behind the adverse effects on animals and the ambient environment as majority of quantity are dumped without being recycled or reused owing to a lack of awareness or infrastructure. This study explored the possible reuse of such post-consumer plastic water bottles as an admixture for altering the soil subgrade properties. The extent of replacement and sizes of waste material are the key aspects for improving the geotechnical parameters. So, this study focused on investigating the impact of plastic waste content and size through standard compaction, California Bearing Ratio (soaked and unsoaked), expansion ratio, and resilient modulus on stabilized soil subgrade. The series of experiments were conducted by varying the plastic waste content with 0%, 0.2%, 0.4%, 0.8%, and 1% of dry soil and two different sizes of waste strips with aspect ratios 2 and 4. It was discovered that adding plastic waste noticeably improves the behavior of stabilized soil subgrade under extreme conditions. Among the various combinations, laboratory test result of mix with 0.4% plastic content and strips with width 5 mm and length 10 mm shows the significant improvement in strength properties. Thus, this research provides an important approach to use waste plastic bottles for the construction of subgrade in order to lessen harmful impact of waste plastic bottles on living organisms and environment.