Review on Long-term Stability of HDPE Geomembrane

Anti-seepage performance of high density polyethylene(HDPE) geomembrane at the bottom of landfill will downgrade due to oxidative degradation,which would cause risk of secondary pollution to environment.Therefore long-term stability of HDPE geomembrane worths attention while few studies have been done in China so far.Divided into three stages,the degradation process of HDPE geomembrane is affected by properties of geomembrane,temperature,exposure media and structure of liner.Laboratory methods on long-term stability of HDPE geomembrane were reviewed,corresponding mathematical model was summarized.Suggestions were given according to the existing problem.Aging test is widely used as indoor test,which includes both immersion test and simulation test that can accelerate the aging process of HDPE geomembrane.For the former,sample will be immersed completely into the research media with a more conservative result,while the latter,sample will be tested in the experimental liner structure,and results shall be much closer to reality.Arrhenius model is used as mathematical model,with the accuracy and parameters depending on the aging test.Most results calculated are unilateral for now and improvement of the experimental research will still be a key point for subsequent work.