Abstract: Geosynthetics are composite materials manufactured using different types of polymeric fibres, usually employed as anti-reflective cracking systems in asphalt pavements. Materials that compose geosynthetics can be damaged due to mechanical and thermal effects produced during the installation process under hot mix asphalts. In this paper, different polymeric fibres extracted from geosynthetics have been evaluated using nanoindentation tests. The main objective was to evaluate the effect of installation process (dynamic compaction and thermal damage) on the mechanical behaviour of individual polymeric fibres at nano-scale. To do this, elastic modulus (E) and hardness (H) of three different polymeric fibres commonly used in geosynthetics (polypropylene, polyester and polyvinyl-alcohol), in two testing directions and under two different states have been studied. Main conclusions of this work are that mechanical properties of geosynthetics individual fibres can change after installation, producing changes in the behaviour of geosynthetics at macro-scale with consequences in the pavement functionality, and that these changes are different depending on the material that composed the fibres. (C) 2016 Elsevier Ltd. All rights reserved.