Development of a PET - concrete culvert using PET aggregates and stone aggregates

Abstract

The study which is entitled as Development of a PET- Concrete Culvert using PET Aggregates and Stone Aggregates was carried out to investigate the possible applicability of polyethylene terephthalate (PET) waste as a substitution of natural aggregates in the production of concrete culverts. The situation of plastic waste being a significant environmental issue in Uganda has overwhelmed the drainage systems, a reduction in the capacity of landfills, and urban flooding. In the meantime, the escalating price and availability of natural aggregates have raised the price of construction materials which have demanded the need to have sustainable alternatives and cost-effective materials. This research therefore aimed to come up with a PET-concrete culvert, which can be described as partially replacing coarse stone aggregates with PET aggregates, characterize the materials, develop the optimum mix design and test and simulate the structural performance of the culvert using the experimental testing method and using finite element modeling method. In the study, the researcher adopted experimental design approach with the sample being PET agglomerates of recycled beverage bottles (Rwenzori, Pepsi and Coca-Cola) and mineral agglomerates of Namagumba quarry and River Malaba. Laboratory tests were done in the Busitema University and ministry of works and transport laboratories. The water to cement ratio was at its optimum level of 0.45. Culvert structural behavior was simulated and modeled in the COMSOL Multiphysics software. Findings demonstrated that the PET aggregates and mixes with 1.0% replacement with PET had good chemical and physical properties, and a mix with 1.0 percent PET replacement had higher compressive strength of the mix at 28 days than the control samples. The further evidence of the analysis of the finite elements was the increased ductility, deformability, and the ability to absorb energy in the best proportion of PET. The study has found that flexural performance of concrete may be improved and sustainable waste management provided by use of PET aggregates. Nevertheless, PET in excess of 1.0% has a great impact on lowering strength. PET-concrete has been suggested to be used in those types of structures that do not depend on tension like culverts, pavements, and wall panels. Future studies need to be aimed at determining the long-term stability and chemical resistance of PET-modified concrete subjects to different environmental environments.