Micro-mechanical properties of geotextile fibers: measurement and characterization at cold environmental conditions

Abstract

One of the most important properties of a fabric (geotextile) and also one of the focus areas of the current research study is its tensile strength, and thus, mechanical properties (modulus, resilience, strength, toughness). To this end, the mechanical properties of the geotextiles must properly be evaluated at the "macro-scale" as well as at the "micro-scale" as they are fibrous synthetic materials including polymeric fibers as well as significant volume of void space. As being a polymer, the mechanical behavior of the geotextile micro-fibers is highly dependent on the ambient conditions including particularly the temperature. In light of this, the tensile behavior of geotextile single micro-fibers was characterized by performing micro-mechanical tensile tests at "micro-scale" level at different cold temperature conditions using Dynamic Thermo-Mechanical Analyzer (DMA) to measure the developed "micro-scale" tensile stress-strain behavior of geotextile micro-fibers. The results examined from the influence of micro-mechanical properties of polymeric fibers on the observed temperature dependent stress-strain curve were used to determine the modulus of elasticity (E), modulus of resilience (UR), ultimate tensile strength (τmax), amount of plastic strain (εp), toughness (UT), rupture strength (τR) for the polypropylene (PP) micro-fiber of needle-punched nonwoven (NPNW) geotextile and the variation in those important mechanical properties with a change in ambient temperature conditions. The experimental results show that the mechanical properties of the PP fibers do not remain constant within the common range of cold temperatures (-10 °C-21 °C) found in typical civil engineering applications such that the temperature change was found to be an important factor affecting the PP fiber micro-mechanical properties such as modulus, strength, toughness and plastic elongation. Therefore, the test results provide an index of behavior at "micro-scale" level for the polymeric geotextile single fibers at cold temperature conditions.