Internal temperature change of various types of geomembranes subjected to tensile test

Geomembranes are nowadays commonly used for waterproofing of dams around the world. One characteristic taken into consideration while designing a geomembrane for a site is their tensile strength. Up to now, it is well established that the tensile strength of geomembranes is temperature dependent. For the typical polymers of geomembranes (Bitumen, EPDM, HDPE, PVC, PP), the greater the temperature during the test, the lower the tensile strength and vice versa. To obtain comparable results between different geomembranes and between different laboratories that perform tensile tests on geomembranes, the typical test standards require a constant temperature during the test. However, when a geomembrane specimen is subjected to a tensile force, the phenomenon of heat dissipation due to the deformation of the specimen can locally modify the constant temperature conditions and therefore the behaviour of the specimen subjected to the test. This paper focuses on quantifying the internal temperature change for various types of geomembranes during tensile tests in an attempt to better characterize the tensile strength of geomembranes. For this research, a thermal infrared camera was used to quantify the temperature change during tensile tests. Through numerous laboratory tests, it was found that the internal temperature change during tensile tests is not the same for the various types of geomembranes and is not uniform during the test. The temperature rise is significant for certain geomembranes such as, PVC and HDPE, while it is insignificant for others such as, bitumen. These results suggest that the composition of the geomembranes is the major reason that explains the various observed behaviours.