Integrating Microplastic and Marine Litter into Sustainable Construction Materials

Abstract

Due to the alarming increase of plastics, especially marine litter, global concern is raised, and attempts are made to repurpose the wastes collected to improve the waste management system. This is because unlike organic waste, plastic wastes need more time to decompose and can harm marine life if washed into the sea. While global attempts are made when it comes to plastic recycling, the percentage of plastics that are eligible for reusing does not cover all. Therefore, it is necessary to include different sectors, and specially the construction sector that is continuously growing, in the attempt of plastic repurposing without the need of further processing. Incorporating plastic waste and marine litter in concrete can be an effective approach to reuse plastics, avoiding unnecessary processing. This in return creates a construction material that is viable for structural use and may provide an improvement on traditional concrete. More importantly, plastic wastes have shown a potential of being used as a partial replacement for both fine and coarse aggregates in cement and concrete, which can contribute to the preservation of both sand and gravel sources as they are both depletable natural materials. Further, the plastics replacement will lead to the production of a lightweight concrete that would help in the alleviation of the total cost for materials and handling, and with the reduction of the total self-weight of the building. This research will investigate the effects of different replacement percentages and sizes of plastics in concrete mixes. Replacement percentages adopted in this research are 10 and 15% for both coarse and fine aggregates, then, based on results, optimal replacement percentage is chosen. Then the effects of different plastic particle sizes, raw and shredded, will be investigated. The physical properties of concrete such as density and weight are observed, as well as the mechanical properties such as compressive, flexural, and tensile strengths, and ductility. After conducting the experimental program proposed for this research, which evaluated mechanical and physical properties of plastics incorporated in concrete, it was concluded that 10% replacement of natural aggregates is the optimal percentage compared to 15% replacement. Then it was found that 10% replacement of sand with shredded plastics results in better concrete qualities in comparison with 10% replacement of coarse aggregates with raw plastics, and this was attributed to the even distribution of shredded plastic particles.