Optimisation of recycled polyethylene terephthalate plastic bottle fibres in glasscrete

Abstract

Cement and concrete production which accounts for between 5% to 8% global CO2 emission are a growing environmental concern considering their high construction dependence. These coupled with non-biodegradable household and industrial waste such as PET plastic and glass have brought about rapid environmental degradation. Following a global concern for environmental conservation, steady strides have been taken in the field of recycling to reduce the waste foot print and increase sustainability. Glasscrete was then developed which is concrete with a percentage cement replacement with glass powder of <75µm (has pozzolanic properties) that performed 2% better than regular concrete at 28 days. To further this effort, this experimental research considered the glasscrete C20 (at 10% cement replacement) and added PET fibres (of aspect ratio 25) at different percentages of 1%, 2%, 3%, and 4% the weight of cement in a bid to optimise the glasscrete performance and its ability to absorb PET waste. Glasscrete being extremely brittle, benefited from the PET addition and failure was by cracking at all percentage additions. It was found that 1% PET fibre addition to glasscrete was optimum and exhibited the highest compressive and flexural strength in comparison to other percentage additions and regular concrete of the same class. Its durability was also 1.5% better than regular concrete of the same grade. Despite this, a 1% fibre addition decreased the compressive strength of glasscrete by at least 3.5% at 28 days and 6% at 90 days and improves the flexural strength by 5.4% at 28 days and 0.8% at 90 days testing. These findings prove the potential of a green concrete with glass and PET waste as a sustainable solution to environmental conservation efforts and is strongly recommended for practical field application and further research development.