Estimativa comparativa da meia-vida de geomembranas expostas às condições climáticas de Manaus/AM

Abstract

Polymeric geomembranes are widely used in environmental engineering works, espe- cially in landfill liner systems, leachate ponds, and containment structures. When exposed to environmental conditions, these materials may experience progressive reduction in me- chanical properties due to the combined effects of ultraviolet radiation, temperature, and atmospheric oxygen. In this context, this study aimed to estimate and compare the half- life associated with tensile strength and elongation at break of different types of geomem- branes exposed to the climatic conditions of Manaus, Amazonas, Brazil. The geomem- branes analyzed were HDPE, LLDPE, fPP, EPDM, and European PVC, based on the ex- perimental data presented by Koerner, Hsuan and Koerner (2017), which were adapted to local environmental conditions. The landfill located on the access road at km 13 of BR- 174 was used as a contextual reference due to the presence of an exposed geomembrane observed through historical Google Earth images. However, no field sampling, laboratory testing, or direct characterization of the installed material was performed. Meteorological data for Manaus were obtained from INMET, and the global solar radiation, ultraviolet radiation fraction, and representative air temperature were estimated for the analyzed pe- riod. The methodology consisted of adapting the half-life prediction procedure proposed by Koerner, Hsuan and Koerner (2017), using digitized reference points, equivalent UV energy conversion, and adjusted relationships between temperature and half-life for the climatic conditions of Manaus. The results indicated differences among the analyzed ma- terials and between tensile strength and elongation at break, showing that the critical property may vary according to the type of geomembrane. The estimates obtained for Manaus were close to those reported for Phoenix, Arizona, with differences compatible with the similarity between the adopted UV radiation values. The results should be inter- preted as comparative estimates based on materials reported in the literature, and not as a diagnosis of the remaining service life of the geomembrane installed at the landfill.