Fleury Mateus Porto, Nascimento Lucas Deroide do, Valentin Clever Aparecido, Lins da Silva Jefferson, Luz Marta Pereira da
São Carlos School of Engineering (EESC), University of São Paulo (USP), São Carlos 13566-590, Brazil.
Eletrobras, Furnas Centrais Elétricas S.A., Aparecida de Goiânia 74923-650, Brazil.
Polymers (Basel). 2021 Feb 28;13(5):752. doi: 10.3390/polym13050752.
At the beginning of this century, due to well-established Brazilian recycling processes, geosynthetics' manufacturers started to use recycled poly(ethylene) terephthalate (PET) yarns/filaments (from PET bottles) in geotextile production. Despite the fact that recycled products cannot act as reinforcement functions, geosynthetics are constantly under sustained tensile load and experiences evolutions of the axial strain (creep behaviour). Thus, this study aims to assess the influence of the structure of (needle-punched) non-woven geotextiles manufactured using recycled PET yarns on their creep behaviour. Two geotextiles with different fibre/filament production processes were investigated (short-staple fibres-GTXnwS-and continuous filaments-GTXnwC). Unconfined in-isolated conventional and accelerated (using the stepped isothermal method) creep tests were performed at 5%, 10%, 20%, 40% and 60% of geotextiles' ultimate tensile strength. The geotextiles investigated provided similar creep behaviour to geotextiles manufactured with virgin PET material. The standard deviation of the axial strain tends to increase as the load level applied increase. The structure of the GTXnwS harms its tensile -strain behaviour, promoting axial deformation under sustained loads, at least 50% higher than GTXnwC for the same load level applied. The influence of the load level and geotextile structure in the initial axial strain is pointed out. Long-term predictions based on creep tests performed using the stepped isothermal method have proven to be conservative and they must be restricted for quality control of the investigated geotextiles.
本世纪初，由于巴西成熟的回收工艺，土工合成材料制造商开始在土工布生产中使用回收的聚对苯二甲酸乙二酯（PET）纱线/长丝（来自PET瓶）。尽管回收产品不能起到增强作用，但土工合成材料始终承受持续的拉伸载荷，并经历轴向应变的演变（蠕变行为）。因此，本研究旨在评估使用回收PET纱线制造的（针刺）非织造土工布结构对其蠕变行为的影响。研究了两种采用不同纤维/长丝生产工艺的土工布（短纤维-GTXnwS-和连续长丝-GTXnwC）。在土工布极限抗拉强度的5%、10%、20%、40%和60%下进行了无侧限常规和加速（采用阶梯等温法）蠕变试验。所研究的土工布的蠕变行为与用原生PET材料制造的土工布相似。轴向应变的标准偏差往往随着施加的载荷水平增加而增大。GTXnwS的结构损害了其拉伸应变行为，在持续载荷下会促进轴向变形，在相同载荷水平下，其轴向变形比GTXnwC至少高50%。指出了载荷水平和土工布结构对初始轴向应变的影响。基于采用阶梯等温法进行的蠕变试验的长期预测已被证明是保守的，并且必须限制用于所研究土工布的质量控制。
