Optimization of fiber-reinforced concrete composite with recycled aggregate and fiber produced with mixed plastic waste

Abstract

The concept of recycling single-type plastic wastes sorted from post-consumer waste streams in concrete materials as a sustainable alternative to natural sand and virgin reinforcement fiber has been widely explored in the literature. However, plastic wastes present in post-consumer waste streams largely vary in terms of polymer types, grades, shapes, and sizes among other cross contaminated waste materials. Hence, adoption of results from past studies which require single-type plastic wastes of high purity for use in concrete remains challenging in practice. Therefore, this study proposes the development of mixed plastic aggregate (MPA) and mixed plastic fiber (MPF) with similar polymer composition to those of mixed plastic wastes in post-consumer waste streams. The Taguchi method with multi-responses utility concept was applied to formulate an optimal high strength mixed plastic fiber-reinforced concrete composite (MPFRCC) mixture incorporating MPA and MPF. Six quality characteristics, such as slump, surface resistivity, compressive strengths at 1, 7 and 28 days and flexural strength at 28 days were characterized based on four three-level design factors, namely polymeric composition of MPA and MPF, MPA replacement level by volume of natural sand (NS), MPF content by volume of total mixture and water/cement ratio. This work demonstrates a promising and effective approach to assimilate the continual generation and accumulation of mixed plastic waste whilst reducing the reliance on consumption of NS and synthetic virgin fiber by the construction industry using recycled MPA and MPF in MPFRCC for building and infrastructural applications.