Properties of concrete containing polyethylene terephthalate and artificial lightweight aggregates: a case study

The use of waste materials in construction and building materials has captured the attention of scholars in recent years. The artificial lightweight aggregates (ALWAs) produced by using the waste materials are a suitable alternative to the natural aggregates. This work proposes a multicriteria decision model to select the ALWAs through an experimental process. The integrated mechanical (crushing test), environmental (life cycle assessment), and economic (life cycle costing) analysis was carried out for ALWAs to choose the most suitable aggregate. Three samples of the aggregate were developed by using cement (5%, 10%, and 15%), industrial waste-like fly ash (80%) (obtained from municipal waste incineration plant), ground-granulated blast furnace slag (5%, 10%, and 15%), and marble sludge (70%). Through the implementation of the analytic hierarchy process model, preferred scenarios are environmental, economic and mechanical performance were applied to the ALWAs samples. According to the outcomes, using the ALWA with 80% FA, 5% ground-granulated blast furnace slag, and 15% ordinary portland cement (OPC) is the most suitable solution. A case study explored the use of single and double-step cold bonding pelletization processes to produce ALWAs. The composition of the aggregates was similar to that reported in the previous study, but the pellet composition differed. These ALWAs were used to create light concrete (LC), and a portion of the ALWAs was replaced with recycled polyethylene terephthalate (PET). LC made solely with ALWAs exhibited lower compressive strength and thermal performance compared to the reference concrete. However, the addition of PET further reduced the mechanical performance, while enhancing thermal conductivity. This type of concrete utilizes industrial waste, reduces cement usage, and improves economic and environmental performance.