Test on effect of temperature on area of thermal expansion of HDPE geomembrane

Abstract

Thermal expansion of High Density Polyethylene geomembrane usually results in wrinkles in HDPE geomembrane in seepage control system of the landfill site. In order to analyze the effect of temperature on the thermal expansion of HDPE geomembrane, the area of thermal expansion of HDPE geomembrane under different environmental temperature and different heating time was measured. Test results show that the area of HDPE geomembrane changes with increasing of environmental temperature and heating time. Under same temperature, the area of HDPE geomembrane increases with increasing of heating time. The increase rate of area of thermal expansion decreases nonlinearly with the increasing of heating time. A fast increase rate of area of thermal expansion is observed during 30 min in incipient stages of heating time, the area of thermal expansion accounts for 34 % of the total area of thermal expansion. At the same heating time, the difference of increase ratio of area of thermal expansion of HDPE geomembrane, between 60 and 40 ºC, increases nonlinearly with the increasing of heating time. The difference of increase ratio of area of thermal expansion increases rapidly during 30 min in incipient stages of heating time. Increase ratio of area of thermal expansion of HDPE geomembrane at 60 ºC is from 2.5 to 3.9 times that of at 40 ºC.