Laboratory Degradation of a Reinforcement PET-PP Geocomposite Under Accelerated Weathering Conditions

Like other polymeric materials, geosynthetics have a limited resistance to weathering. The exposure to solar radiation and other weathering agents (e.g. air, heat or moisture) can result in undesirable changes in their properties, affecting their performance and reducing their service life. The weathering resistance of geosynthetics can be evaluated by field or laboratory tests, under natural or artificial conditions, respectively. Field tests are usually time-consuming, with laboratory tests being an alternative to simulate (in a short period of time) outdoor weathering. This work evaluates the laboratory degradation of a PET-PP geocomposite [a polypropylene (PP) geotextile reinforced with polyethylene terephthalate (PET) filaments] under different accelerated weathering conditions. The artificial weathering tests were performed in a laboratory weatherometer [fluorescent ultraviolet (UV) lamps type] and included exposure of the geocomposite to UV radiation, water spray and condensation. The geocomposite was tested on both sides (which were structurally different) and both manufacturing directions. The effect of many parameters of the weathering tests (namely, composition of the weathering cycle, UV exposure temperature, UV irradiance, UV radiant exposure and test duration) was evaluated. The degradation suffered by the geocomposite (in the weathering tests) was assessed by monitoring changes in its tensile behaviour. The results, among other findings, showed that UV radiation was mainly responsible for the degradation of the geocomposite in the weathering tests. The effects of UV radiation were enhanced by increasing temperature or using higher UV irradiances. The increase in the total duration (or UV radiant exposure) of the weathering tests also resulted in a more pronounced degradation of the geocomposite.