Evaluation of the Mechanical Performance of Concrete Reinforced with PET Fibers: A Sustainable Approach

Most of the bottles manufactured with PET polymer (polyethylene terephthalate) are used in beverage packaging and, after use, are turned into garbage, causing environmental problems. The concept of recycling and reuse of these materials for use in civil construction can become an interesting solution for the reduction of urban solid waste that would be destined to the formation of large volumes in sanitary landfills. Seeking to minimize this problem, this work used discarded PET bottles, ground into fibers, to prepare a concrete-based composite. The behavior of concrete composites with the addition of PET fibers in different compositions 7.5 kg/m³, 10 kg/m³ and 12.5 kg/m³ was evaluated. The choice of these concentrations aimed to study the addition of a reasonable amount of PET, characterizing greater reuse of a recycled material, seeking to provide a reinforcement effect in the cementitious matrix. The samples were subjected to mechanical tests of axial compression and diametral compression in a duly calibrated hydraulic press. For the axial compression test, the composite with 10 kg/m³ showed better mechanical performance. Probably at this content, the fibers were better distributed in the concrete for axial compression, resisting more to the fracture point, surpassing the composite of 12.5 kg/m³ by 24% in resistance to compression. For the axial compression test, the composite with 10 kg/m³ showed better mechanical performance, because in this composition there was an ideal amount for the homogenization of the PET fibers in the concrete, achieving a greater reinforcement effect. For the permeability test, the composites prepared with higher percentages of PET showed a lower percentage of permeability (44% lower than the content of 7.5 kg/m³), absorbing less water in this composition, in an axial position. This can be attributed to the fact that the distributed PET fibers act as an impermeable barrier, offering greater resistance to water absorption in the material.