Geomembrane Thermal Expansion and Contraction 

Q: We are installing geomembrane in extreme weather conditions. We’ve been talking to a client who has a high thermal gradient where temperatures vary in the same day from 55°C to 0°C. He’s been asking us about the thermal expansion and contraction that the geomembrane can present on the field. Is there a number he can expect for various geomembranes? I know that all geomembranes will have an expansion and contraction issue and that it’s almost always related to the thickness. Do you have any studies/research in mind that you can recommend?

A: Yes. GSI has done work on the thermal coefficient of expansion and contraction of geomembranes. Please see: Koerner, G.R., and Koerner, R.M. (1995). “Temperature behavior of field deployed HDPE geomembranes,” from Geosynthetics ’95 Conference IFAI proceedings, Nashville, Tenn. This paper talks about field monitoring and the theoretical calculations from RMK’s Designing With Geosynthetics.

I can tell you the following are all factors affecting the thermal coefficient of expansion and contraction:

• Thickness
• Color
• Scrim reinforcement
• Polymer type
• Formulation
• Fabrication (cast vs. blown)
• Direction (machine vs. traverse); most materials are not isotropic