Experimental Investigation on Fresh and Mechanical Properties of Waste Plastic Aggregate-Based Concrete

Utilizing waste plastics as substitutes for natural aggregates in cement concrete composites offers a promising solution to various environmental pollution issues. This research aims to explore and contrast the effects of integrating waste polyethylene terephthalate (WPET) as coarse aggregate replacements in M30 grade concrete. Evaluations encompassed both fresh and hardened concrete, examining aspects such as density, workability, compressive strength at 28 days, split tensile strength, flexural strength, and ultrasonic pulse velocity. Nine concrete mixtures incorporating WPET were formulated, varying the substitution levels from 0 to 40% along with 5% gap, while maintaining a constant water-cement ratio of 0.37. The application of super-plasticizers notably enhanced the workability of WPET-infused concrete. Density measurements indicated a reduction with increasing WPET content, suggesting potential for lightweight concrete formulations. However, compressive strength exhibited a decreasing trend with higher proportions of WPET in the mix. Similarly, flexural strength and split tensile strength experienced declines as WPET replacement ratios rose. Furthermore, ultrasonic pulse velocity demonstrated a negative correlation with compressive strength as WPET content increased. Additionally, cost comparisons and optimization of mix proportions were conducted using factor response optimizer, guided by concrete composite desirability of 0.9784.