Performance of Flexible Pavement Systems Containing Geosynthetic Separators

From TRB’s Research-in-Progress Library: Richard Coffman is investigating if geosynthetic separators have prevented plastic “clayey” fines from migrating into the base layer from a prepared subsoil. The in-situ fines content at the site will also be compared with the preplaced quarry obtained fines content to determine if additional fines are created during transportation, placement, and use of the roadway base. Base course drainage, strength, and modulus are important parameters that must be considered in the design of a roadway system. Pavement service life is maintained if the base course is permeable, strong, and rigid. Two recent Mack Blackwell Transportation Center (MBTC) projects have focused primarily on the rigidity of pavement systems. MBTC Project 2027 focused on the strength, permeability, and rigidity of quarry obtained, preplaced, Class 7 base course using laboratory tests; while MBTC Project 3013 is investigating the effects of geosynthetic separators, geosynthetic reinforcement, and base course thickness on pavement system rigidity.