Evaluating wettability of geotextiles with contact angles

Abstract

Geotextiles have been used for drainage purposes in pavements for many years. To drain water out of road sections, the geotextiles need to get wet first. In this study, the wettability of three different types of geotextiles, namely wicking woven (WW) geotextile, non-wicking woven (NWW) geotextile, and nonwoven (NW) geotextile, was investigated in terms of their contact angles dependent on water-geotextile interaction. Contact angle was observed by the VCA Optima XE tensiometer for up to 12 s after a water droplet was dropped at the center of a geotextile's surface. Water droplets of two different sizes (2 μL and 5 μL) were used to demonstrate the droplet size effect on the contact angles of water on undisturbed geotextiles. Test results show that the contact angle decreased to smaller than 90° and the droplet disappeared on the wicking woven geotextile within a few seconds after water dropping, while the contact angle remained larger than or approximately equal to 90° on the other two types of geotextiles within the observation period. This comparison indicates that water penetrated faster into the wicking woven geotextile than other geotextiles. Furthermore, this study investigated the effects of soil particle intrusion and geotextile or fiber deep groove flattening associated with compaction on the wettability of geotextiles.