The Effects of Shredded Polyethylene Terephthalate (PET) Waste as Partial Substitute for Conventional Fine Aggregates on the Engineering Properties of Concrete

Abstract

This work assesses the possibility of using shredded PET waste as partial replacement of conventional fine aggregate in concrete at 0 %, 5 %, 10 %, 15 % and 20 % replacements. The workability, density, water resistance and compressive strength of PET-modified concrete were investigated and compared with a control mix concrete containing 0% PET. These properties were determined according to the recommended British standard codes. Concrete was produced using a mix ratio of 1:2:4 and water-cement ratio of 0.5 which served as the control mix. The slump test results show decreasing slump with addition of PET flakes, with 20% PET content having the least slump of 30mm, implying that addition of PET increases the harshness of concrete. Also, it follows that density of concrete reduces with increasing PET content, with 20% PET showing the lowest density of 2334.81kg/m3. However, water absorption test shows decrease in water resistance with addition of PET flakes  but 5 % PET gave highest water absorption capacity of 2.15%. On the other hand, compressive strength test assessed at curing ages of 7, 14 and 28 days shows that strength reduces with addition of PET at each curing duration and also, increases with curing duration. Concrete with PET content not higher than 5% yielded compressive strength of 23.6 N/mm2 at 28 days of curing which is very suitable for structural applications. The study suggests that PET wastes instead of creating environmental problems should be used in concrete production to promote green and sustainable construction.

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