Aproveitamento de resíduos de garrafas de PET para reforço de um solo argiloso

Abstract

The production and consumption of products disposed in polyethylene terephthalate (PET) packaging has been growing very significantly over the last few decades due to population growth, which, in turn, increases the demand and consumption of industrialized products. As a result, the generation of non-degradable waste grows every day, and represents a major environmental problem, as plastic packaging has a long decomposition time, requiring large spaces to be disposed of in landfills, in addition to which they are often discarded. inappropriately in nature. Therefore, it is known that the reuse of waste tends to minimize environmental impacts, preserving natural resources, and contributing to environmental sustainability actions. On the other hand, in Geotechnics, problems are often encountered in the execution of works when the properties of the soil available at the site do not meet the criteria required for the project. That is, when the natural soil does not fit the technical specifications for a given application, it is necessary to employ some technique to improve its properties. In this context, the use of recyclable materials, including polymeric ones, has been increasing in geotechnical engineering for soil reinforcement. Given this scenario, this research proposes the use of PET bottle waste as an alternative solution to improve the shear strength of a clay matrix soil. For this, the effects of the inclusion of PET, in micronized and fillet forms, in different contents and lengths, on the mechanical behavior of a clayey soil were evaluated, based on the results of unconfined compressive strength, direct shear and triaxial compression consolidated undrained (CU). In addition to these, their effects on the hydraulic conductivity of the mixtures in relation to the matrix were also analyzed. The results obtained for all resistance tests showed that both the micronized PET and the PET fillet added an improvement in the resistance of the mixtures in relation to the pure soil. It was found that the two types of PET contributed more significantly with increases in the cohesive portion of the matrix, and the PET fillet predominantly promoted a greater increase in the value of cohesion/cohesive intercept of the mixtures in relation to pure soil, when compared to PET micronized. Of the contents and lengths tested, the 5% content for micronized PET, as well as the combination of 0.5% content with a length of 15 mm for the PET fillet were the ones that proved to be the most suitable in providing greater gains in soil resistance. , especially the cohesive. As for hydraulic conductivity, the results obtained showed that PET made the mixtures more permeable when compared to the non-reinforced matrix. Therefore, it is concluded that the use of PET (micronized and fillet) as a reinforcement of a clayey soil is technically viable, because in addition to contributing to resistance, it enables a mitigating action of the serious impacts generated by the residues of this material, since it suggests a nobler destination for this environmental liability, often inappropriately discarded in nature.