ABSTRACT
The use of directional dependency, anisotropy, of the modulus and deformation characteristics is introduced in this paper to evaluate the effectiveness of sand-geofiber stabilization for rapid road and airfield construction. An advanced triaxial testing machine named University of Illinois FastCell (UI-FastCell) is used for determining the anisotropic resilient moduli of two geofiber reinforced sands (poorly and uniformly graded sands) prepared using three 51-mm geofibers, fibrillated, monofilament, and tape. The use of different geofiber types and the varying amounts of clay and silt fines present in the sand mixtures significantly affected the recorded horizontal and vertical moduli and the ratio of the two moduli. Monofilament type geofiber stabilization was found to be the most effective for improving modulus and deformation characteristics giving the highest vertical moduli and the lowest deformations especially when mixed with 10 to 20% clay. Without the added plastic fines, control (no geofiber) samples often gave the best performances thereby indicating no improvement by geofibers.
