This presentation describes four different applications of geosynthetics in the reconstruction of roads in northern Minnesota. Installations are on paved and unpaved low volume county roads, medium volume paved county roads, and a state trunk highway. County road projects use geotextiles for separation and strengthening of weak, lake deposited, subgrade soils; including a unique project at the Northwest Angle (the chimney of Minnesota) where geotextiles were used to provide a passable road during spring breakup. The state trunk highway project consists of geocell, geogrid, and geotextile sections constructed in sequence to determine which is the most cost effective. Most installations will have been in place in excess of 5 years by 2001. Maintenance benefits to date include reduced longitudinal and transverse cracking of pavements, reduced or eliminated frost heave, reduced blading and regraveling of aggregate surfaced roads. Design benefits include reduced base course thickness requirements and improved constructability of roadbed over soft subgrades. Construction techniques used allowed for ease of placement and efficient contractor operations. Rules of thumb have been developed through practical experience to determine when and where to use geotextiles.
