Upcycling Agricultural and Plastic Waste for Sustainable Construction: A review

The production of conventional construction materials such as concrete, cement, and bricks, has contributed significantly to the high environmental footprint associated with the construction industry. Moreover, there is a global push to deviate from the linear take-use-dispose model to a circular economy model, which incorporates upcycling and reuse of materials. This paper reviews the application of agricultural and plastic wastes, in construction, exploring the performance of the resulting component using five key parameters: compressive strength, tensile strength, flexural strength, density, and thermal conductivity. The study showed that the compressive, tensile, and flexural strengths can be increased slightly by increasing waste content, however, this only occurs in a narrow range after which an increase in waste content reduces the mechanical strength. This reduced strength can be attributed to a weaker bond resulting from the increased waste content. It also suggests that components may not directly benefit from the mechanical properties of waste materials. The waste materials resulted in a lower density which has implications for lightweight applications. Similarly, both waste materials were observed to improve the thermal insulation properties which is an advantage for improving thermal comfort in buildings. Despite the reduction in mechanical strength, it was observed that components with waste materials can be used for non-structural elements, thereby reducing the quantity and cost of new materials to be used. The application of these wastes in construction offers a pathway to reducing the environmental impact of construction, avoiding reliance on landfills for waste disposal, and reducing construction costs.