Use of recycled plastic in self-compacting concrete: A comprehensive review on fresh and mechanical properties

Due to manufacturing processes, municipal solid wastes and service industries, huge amount of waste materials are generated. Recently, a considerable growth in the plastic consumption across the globe can be observed. This has caused enormous quantities of plastic-related waste. Producing new materials such as mortar or concrete from recycling of plastic waste (PW) seems to be one of the best solution for disposing of PW since it is considered to be environmentally and economically advantageous. In modern constructions, self-compacting concrete (SCC) is employed as a main cementitious material, which functions complex formworks without mechanical vibrations with high segregation resistance and greater deformability. Reuse of recycled plastic (RP) in SCC mixes can provide an environmentally friendly and sustainable construction material. Therefore, it has been an ongoing topic for several researches, and a large number of studies investigating the properties of SCC comprising waste and RP materials have been conducted. In this study, the current and most recent literatures considering plastic recycling method and the influence of plastic materials on the fresh and mechanical properties of SCC are summarized. So that a comprehensive review can be provided in which the reviewed studies are categorized into sub groups based on whether they dealt with SCC containing plastic aggregates (PAs) or plastic fibers (PFs). Furthermore, the effect of RP on the fresh and mechanical properties of various self-compacting composites like self-compacting mortar (SCM), self-compacting high strength concrete (SCHSC) and self-compacting light weight concrete (SCLC) have been reviewed to illustrate the differences with normal SCC. The empirical relationships among various mechanical properties were also developed. Based on the obtained results from previous studies, recycled plastic self-compacting concrete (RPSCC) can be used for structural applications due to its satisfactory fresh and mechanical properties. Moreover, this type of concrete is environmentally friendly and sustainable product due to replacing the natural aggregates (NA) with plastic materials.