Avaliação da adição de polietileno tereftalato (PET) no controle da expansão dos solos.

Abstract

Growing industrialization and technological advances have resulted in an increase in environmental pollution due to the production of waste and inadequate disposal. Most of these residues are plastic products, mainly Polyethylene Terephthalate (PET). As the current capacity of recycling programs to absorb waste PET materials in an environmentally sound manner is limited, a sustainable option is to incorporate them into civil construction to stabilize expansive soils. From a geotechnical point of view, these are unsaturated soils that present volumetric variations resulting from the seasonal effects of humidity, causing problems, above all, due to the increase in tensions in the structures, which can reduce the useful life of buildings and even endanger human life. Polyethylene terephthalate (PET) was selected in this study to verify its possible use as an additive to reduce soil expansion, alone and in conjunction with lime. For addition to the soil, micronized PET was used with percentages of 5% and 10% in dry mass and hydrated lime with percentages of 0%, 2%, 4% and 6% in dry mass. Mixtures compacted with soillimePET were prepared at three different dry unit weights (14 kN/m³, 15 kN/m³ and 16 kN/m³) and compared with the control mixtures of pure soil and soillime obtained by Tenório (2019) and Silvani et al. (2020). The soillimePET mixtures were submitted to the unidirectional expansion test following the methodology A of ASTM D4546 (1996). The results showed that the PET content, lime content, porosity and dry specific weight are significant in changing the behavior of compacted mixtures when compared to Tenório (2019) and Silvani et al. (2020), helping to control the expansion of soils. It was also observed that the methodology porosity/volume content of binder adjusted by an exponent (/Liv)a is valid for the study, since it was possible to establish a unique relationship between the expansion and the parameter (/Liv)0,26 with a correlation coefficient (R²) of 80% and 69% for 5% and 10% PET respectively.