Virtual Booth

PET plastic waste is a major environmental problem because it is non-biodegradable and
accumulates in landfills. Meanwhile, concrete production depletes natural aggregates like
sand and gravel. This study investigates using recycled PET bottles as a partial aggregate
replacement to create sustainable concrete, focusing on how it affects workability, density,
and compressive strength. This study aims to determine the effect of PET plastic on
concrete workability and evaluate its compressive strength. By comparing normal concrete
with PET-modified concrete, the research seeks to identify the optimum PET replacement
percentage, ultimately promoting sustainable construction through plastic recycling. The
materials used in this research consist of cement, fine aggregate (sand), coarse aggregate
(gravel), water, and plastic bottles (PET). Waste PET plastic bottles were collected from
recycling sources and surrounding areas, and the bottles were cleaned and dried to remove
impurities before use. The PET bottles were shredded into small particles to act as partial
aggregate replacement material, and these shredded plastic particles were mixed with
conventional concrete materials. Concrete specimens were prepared using different
percentages of PET replacement, which included control concrete (0%), 5% PET
replacement, and 10% PET replacement. Finally, concrete cubes were cast into standard
moulds, and the specimens were cured for 28 days before testing. The 28-day curing results
reveal a significant difference in performance between the two replacement levels. The 5%
PET replacement concrete achieved an average compressive strength of approximately 15.6
MPa. However, increasing the plastic content to 10% PET replacement caused the strength
to decrease to approximately 12.2 MPa. This data confirms that higher concentrations of
PET plastic negatively impact the structural capacity of the concrete mix. The results indicate
that while PET plastic reduces compressive strength due to weaker bonding and lower
stiffness, a 5% replacement remains suitable for lightweight, non-structural applications.
Beyond its mechanical properties, utilizing recycled PET bottles significantly enhances
sustainability by reducing landfill waste and preserving natural aggregates, fostering more
eco-friendly construction practices.