Stabilization of High Plasticity Clay and Silty Sand by Inclusion of Discrete Fibrillated Polypropylene Fibers (Fibergrids) (trade name) for Use in Pavement Subgrades,

The U.S. Army Engineer Waterways Experiment Station WES and Synthetic Industries, Chattanooga, TN, in a joint research effort investigated the advantages of adding discrete fibrillated polypropylene fibers to a silty sand and a high plasticity clay for enhancement of engineering properties. The investigation centered on the use of the materials in pavement layers however, other applications such as slope stabilization have been successfully completed by Synthetic Industries. Various combinations of fibers with raw soils and chemically stabilized soils were placed in test track sections and subjected to trafficking of a single-axle dual-wheel vehicle. Progressive damage due to trafficking was monitored, and various field and laboratory tests were conducted to determine performance of the test sections. Performance of fiber-reinforced sections was determined based on comparison with the performance of sections without fiber added. The trafficking tests showed a definite improvement in strength and durability for the soil materials with fiber added. Uniaxial laboratory tests also reflected improvement in modulus, peak strength, and strain energy density with addition of fibers. Fiber reinforcement, Pavement subgrades, Soil stabilization.