This paper addresses select durability characteristics of a continuous-filament, nonwoven geotextile commonly used in transportation-related applications. Two samples of the geotextile were exhumed from the base of an unpaved road structure located at an industrial site in east texas. The two samples had been in service for 12 and 13 years, respectively. The samples, together with an unused reference sample manufactured at the same time as the exhumed samples, were subjected to a series of destructive mechanical tests, structural analyses, and examinations via scanning electron microscopy. The mechanical tests included measurements of grab-tensile strength and elongation, burst strength, puncture strength, trapezoid-tearing strength, as well as individual fiber strength and elongation. The exhumed samples retained in excess of 70% of their initial strength and elongation properties. The microstructural analyses included differential scanning calorimetry and infrared spectroscopy. The results of these tests indicated that some polymer degradation had occurred such as might be caused by oxidation. The extent of the oxidation is not considered significant because scanning-electron microscopy does not show any circumferential cracking on the fiber surface, a feature that occurs when fiber oxidation is extensive. Scanning electron microscopy did show some mechanical damage on the surface of the fibers; however, this may be ascribed more to installation damage than to degradation during service. This paper appears in transportation researchrecord no. 1248, Geosynthetics, geomembranes, and silt curtains in transportation facilities.
Abstract