Compressive Behaviour of Short Engineered Cementitious Composite Columns Containing Recycled Polyethylene Terephthalate Aggregate

Gough, Tom (2022) Compressive Behaviour of Short Engineered Cementitious Composite Columns Containing Recycled Polyethylene Terephthalate Aggregate. [USQ Project]

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Polyethylene terephthalate (PET) plastic waste is a significant environmental problem. Research has shown that sequestering this waste as a lightweight recycled aggregate in conventional concrete is promising. However, conventional concrete is brittle and has a durability problem.

Engineered cementitious composites (ECC) also known as bendable concrete are a highly durable and ductile fibre-reinforced concrete construction material, typically requiring ultrafine manufactured sand with high cement contents. Consequently, it is costly to produce and has a significant environmental impact. Recycled aggregates can reduce environmental impacts and could help reduce costs.

This study is the first to evaluate the performance of new high fly ash composites utilising locally available natural sand and recycled PET granule aggregates. A control using natural sand was compared to trials volumetrically replacing sand with 10%, 30% and 50% PET granules. A three-step mixing process and a high-shear pan mixer were used to optimise the performance of the composites.

Flexural beams were formed to assess flexural strength and briquette specimens were formed to assess the uniaxial tensile strength of each trial. Cylinder test specimens were formed to evaluate the indirect tensile strength as well as the glass fibre confined and unconfined strength of short columns.

The results indicate that a lightweight strain-hardening composite is achievable using locally available sand and PET granules. Generally, the tensile strain capacity and ultimate strength were reduced as the PET content increased. The compressive strength was reduced by more than 20% with PET granules but an increase in strength with the replacement ratio was observed. The ductility of the columns was increased by 48% with PET granules and a single layer of confinement equalised the ductility between all PET replacement ratios.

Natural sand and recycled PET granules were found to produce a high fly ash ECC with acceptable mechanical properties and short columns with low weight and excellent ductility. Adequate mixing and tailoring of the mixture design would assist researchers to realise the full potential of these new more environmentally friendly engineered composites.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Current – Faculty of Health, Engineering and Sciences - School of Engineering (1 Jan 2022 -)
Supervisors: Lokuge, Weena
Qualification: Bachelor of Engineering (Honours) (Civil)
Date Deposited: 20 Jun 2023 23:51
Last Modified: 20 Jun 2023 23:51
Uncontrolled Keywords: Engineered cementitious composites (ECC); bendable concrete; behaviour

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