Background: The accumulation of post-consumer polyethylene terephthalate (PET) plastic waste poses a significant environmental burden, while the construction industry simultaneously faces growing pressure to reduce dependence on virgin natural aggregates.

Objective: This study examines the effect of replacing natural fine aggregate with shredded recycled PET plastic aggregate, at replacement levels of 0%, 5%, 10%, 15%, 20%, and 25% by volume, on the compressive strength, workability, and water absorption of structural concrete.

Method: A simulated experimental dataset, modelled on patterns reported in published literature on plastic aggregate concrete, was used to evaluate 7-day and 28-day compressive strength, slump, and water absorption across thirty concrete specimens (five specimens per mix group, six mix groups). Data were analysed using descriptive statistics and one-way analysis of variance (ANOVA) in SPSS (version 27).

Key Results: Compressive strength declined progressively with increasing PET content, with a reduction of approximately 43% at the 25% replacement level relative to the control mix at 28 days. Slump increased by approximately 32%, while water absorption increased by approximately 77% at the highest replacement level. Replacement levels up to 10% retained more than 90% of control strength, suggesting a practical threshold for non-structural and semi-structural applications.