Investigation on recycling potential of plastic waste as aggregate in green sustainable concrete: an economic approach

Abstract

Plastic waste management is one of the major global challenges at present. Recycling single used plastic waste as partial replacement of natural aggregates in concrete may encounter the issues regarding mismanagement of plastic waste and unsustainable utilisation of natural resources as aggregates. This concept has been explored in many studies and positive results are obtained in terms of viability regarding mechanical properties of the concrete, but still it has not been materialized at a large scale due to the uncertainty regarding its economic viability. The present study therefore focuses on the economic aspects of using Polyethylene (PE) based fine aggregates and Polyethylene Terephthalate (PET) based coarse aggregates as partial replacement (10%, 20%, 30% and 40%) of natural fine and coarse aggregates separately and simultaneously, with special emphasis given on environmental and social cost. A material flow diagram using STAN (subSTance flow ANalysis) is first developed to calculate plastic waste generation. An industrial survey has been conducted to estimate production cost of plastic aggregates, while social cost as Willingness to Pay (WTP) is determined through Contingent Valuation Method (CVM). The result shows that the total cost of concrete decreases with the increase of replacement percentage and cost reduction varies between 0.65% and 5.42% compare to conventional concrete depending on the percentage and type of replacement without compromising mechanical strength. So, alongside being hugely beneficial to environment and society in terms of reduction of leachate and greenhouse gas generation, micro-plastic pollution, requirement of landfill area, mosquito borne diseases, erosion, sedimentation, land loss etc.; the concept of recycling plastic waste as partial replacement of natural aggregates in concrete has been proved to be economically viable and beneficial too. Based on the result, policy makers can make suitable methodology and specifications for successful implementation of this proposed strategy, which may help the society to achieve a sustainable future.