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.
