Innovative geotextiles with moisture management for resilient roadway

AUTHORS: S.I.S. Teh, and C.J. Jong

Roadway can be built on the ground, embankment or viaduct structure, depending on design considerations such as final road levels, area prone to flooding, etc. For roadways on ground, the road structure is ultimately supported by underlying subgrade soils which is often under unsaturated condition. Moisture can migrate into the roadways structure through capillary rise action and rainfall infiltration. In general, an increase in moisture content of road structural layers and subgrade results in reduction of shear strength and resilient modulus. Wicking geotextile is a relatively new innovation in the geosynthetics industry. The wicking yarns have higher absorbency than surrounding soils due to higher matric suction. Unlike other conventional geosynthetics products, the wicking geotextile not only has good separation, filtration and mechanical stabilization functions, but it has moisture management ability to wick capillary water from soils due to its hydrophilic nature, thus reducing moisture content and improving soil shear strength, and ultimately prolonging the service lifespan of roadways. Several applications of wicking geotextiles in mitigating roadway problems including excessive moisture, freeze-thaw cycle in seasonal countries, cyclical heave and shrink in expansive clayey subgrade will be discussed. Several completed projects in Asia Pacific will also be elaborated.