Feasibility Study of Using Recyclable Polyethylene (PET) Materials as Coarse Aggregate for Concrete Mixtures

The feasibility of using recyclable household plastics, specifically those made of polyethylene, commonly used in water and soda bottles, as a replacement for concrete coarse aggregate, was assessed. A method was developed for cutting polyethylene materials into fibrous strips. These strips were then used as a replacement for the rock coarse aggregate in batches of concrete. Standard 6” x 12” test cylinders were made using the concrete mixture and subject to destructive compressive testing in order to yield the compressive strength of the concrete mix 7, 14, 21, and 28 days after pouring. Three mixtures were tested, one control with no plastics, and two in which 10% of the coarse aggregate volume was replaced with varying levels of plastics. The results of the tests indicated that there was an overall loss of compressive strength in the concrete when the plastic was added. Observations on the mode of failure were also taken, and additional factors affecting the use of plastics in concrete were discussed, including workability and appearance.