Strengthening rectangular columns using recycled PET bottle strips

Consumption of plastic is steadily increasing, making disposal through landfilling, incineration, and open-or closed-loop recycling challenging. The majority of these plastic waste is Polyethylene Terephthalate (PET) bottles, widely used for single-use beverage and liquid containers. This study focuses on using Recycled PET (RPET) bottles as confining material on rectangular concrete columns. This method uses RPET strips that are produced by stripping parts of the RPET bottle which are then wrapped around externally on concrete columns. It can easily be adapted in rural areas with low skilled workers, unlike the conventional methods which makes use of expensive materials and require trained workers. Production of twenty-seven rectangular unreinforced concrete specimens with a size of 100 mm × 100 mm × 300 mm are made. The RPET strips are varied having width of 10 mm and 20 mm, and clear spacing between strips of 10 mm and 25 mm by using two available PET bottles in the industry. A fastening system is proposed, instead of using industrial adhesives, in placing and tying the RPET strips to the rectangular column. Results show a 19% to 70% increase in ultimate compressive strength for rectangular columns which are externally reinforced by RPET. A significant increase in axial strain from the stress-strain diagram is experienced. The proposed method is practical and effective in strengthening concrete structures. The findings suggest that test for long-term durability should be implemented. Life cycle analysis as well as further studies on the scalability of this viable PET waste management solution should be conducted.