Plastic-fly ash waste composites reinforced with carbon nanotubes for sustainable building and construction applications: A review

Abstract

The building and construction industry is the largest consumer of natural resources and contributes towards high volumes of carbon emission. To achieve sustainability in the industry, waste materials have been applied in construction composites such as bricks and cement/concrete mortar to reduce the dependency on non-renewable resources. This review focuses on the application of waste plastics and coal fly ash in building and construction composites, especially bricks. The properties (e.g., mechanical strength, water resistance and thermal stability) of the waste-derived composites were evaluated to ascertain their applicability in the construction industry. Nanomaterials such as carbon nanotubes (CNTs), which are known to possess high mechanical strength have been identified as suitable filler materials to provide the desired strength to the final products such as bricks. The dispersion of the CNTs in the composite is at a finer scale, compared to conventional fillers. Thus, extremely low contents of CNTs can make a substantial difference in enhancing the properties of the composites. The waste-derived composites enhanced with CNTs are lightweight strong materials that can withstand harsh conditions of weather, fire or earth tremors. Moreover, the environmental concerns on the release of CNTs from the composite are reviewed to ensure their sustainable application.