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Today’s geosynthetic products have many useful, creative, and cost-effective applications for rural, low-volume roads. In the management of almost a half-million km (quarter-million mi) of low-volume roads, the U.S. Department of Agriculture, Forest Service (USFS), has developed and adopted many uses for geosynthetics. An overview is presented of many of those uses and their advantages. The USFS gained much of its experience and practice with geosynthetics while constructing a wide variety of Mechanically Stabilized Earth (MSE) retaining walls, including geotextile, timber, modular-block, and tire-faced structures, and reinforced soil slopes. More recently, the USFS has used geosynthetics for MSE bridge abutments and Deep Patch road-shoulder reinforcement. Other typical geosynthetic applications include filtration, drainage, subgrade reinforcement, and erosion control.

In addition, construction delays often force paving past the threshold dates set in HMA paving specifications. This late-season paving has the same detrimental effects on the mat described above. Warmmix asphalt (WMA) seems to offer an alternative by lowering the production, placement, and compaction temperatures of the asphalt concrete. Because WMA is produced at a lower temperature than conventional HMA, it has a slower cooling rate than HMA because of a smaller difference between production and ambient temperatures (1). This difference increases the window of time for effective mat compaction. This attribute is particularly desirable for cold-climate paving and long-distance mix hauling.During the past 6 years, various states have used WMA technology in trial sections and actual paving projects (2-5). In addition, several laboratory studies have assessed and evaluated WMA mixtures and compared their performance with that of conventional mixes (1, 6, 7 ). This paper details a late-season, low-volume roadway paving project that marks the first WMA mixture used in an Alaskan project. Materials and construction information are presented, followed by data for the laboratory and field testing performed on the control and WMA mixtures. Finally, the paper summarizes the experience gained and lessons learned from the project. PROJECT DESCRIPTIONIn 2008, an experimental features in construction project was initiated by the Alaska Department of Transportation and Public Facilities with the cooperation of FHWA to use Alaska's first WMA mixture in an actual construction project. WMA was used in the upgrade of the southern part of the Petersburg-Mitkof Highway, a gravel-surfaced portion of the highway, between mileposts (MP) 17 and 25. This lowvolume roadway on Mitkof Island, in the heart of southeast Alaska's inside passage, links a salmon hatchery (∼MP 17) to a ferry terminal (∼MP 25). Average annual daily traffic consists of 250 vehicles, with 3% trucks.The aim of using WMA was twofold: to minimize the likelihood of construction and weather challenges related to late-season paving and to gain experience with this type of mix technology. The contractor was given the choice of using any WMA technology listed on the FHWA website at that time. The contractor most probably chose the Sasobit organic additive because of its relatively low cost as compared with other WMA technologies and because its use did not require any modifications to the mix plant. Sasobit is a synthetic paraffin wax (long-chain aliphatic hydrocarbon) that reduces binder viscosity at mixing temperatures (8). It is completely soluble in asphalt at above 239°F (its melting point is between 185°F and 239°F). For This paper documents late-season paving of a gravel, low-volume roadway on Mitkof Island in the Tongass National Forest in southeast Alaska. The project was Alaska's first experience with warm-mix asphalt (WMA) technology. In 2008, Sasobit (1.5% by weight of asphalt) was added to a PG 58-28 polymer-modified asphalt at the producer's plant, bargeshippe...

The use and effects of studded tires in Oregon are investigated, updating a 1974 report. Studded-tire use was surveyed, rut measurements collected, studded-tire traffic estimated, and pavement wear and damage analyzed. Studded-tire use in Oregon varies geographically. Half of the vehicles equipped with studs use them on all wheels, representing a significant change from 1974 practices. More than 23 percent of vehicles used studded tires in 1994. Studded-tire pavement wear coefficients were calculated and found to be half those reported previously. The coefficients for rigid and flexible pavements are 0.20 mm (0.008 in.) and 0.86 mm (0.034 in.), respectively, per 100,000 studded tire passes. Studded-tire wear will shorten pavement life on high-volume routes in Oregon. Asphalt pavements experiencing average daily traffic (ADT) volumes of 35,000 and 20 percent studded-tire use will reach the threshold rut in 7 years. Portland cement concrete (PCC) pavements experiencing 120,000 ADT and 20 percent studded-tire use will develop the threshold rut depth of 19 mm in 8 years. These estimates substantially reduce Oregon design life expectations for asphalt and PCC pavements. The estimated Oregon studded-tire damage for 1994 is $37 million for the state highway network, with similar damage for municipal and county roads. Alternatives are discussed to reduce the damage caused by studded tires, including a ban on studs, shortened use period, lightweight studs, user fees, and public education initiatives. Studded tires were introduced in the United States in the early 1960s (1). Since that time, the public has come to associate improved traction and driving safety in winter with the use of studded tires. Numerous references have also indicated that studded-tire use increases the rate of pavement wear for both asphalt and portland cement concrete (PCC) surfaces. The use of studded tires and the extent of pavement rutting attributable to them have been topics of spirited debate in the northern snow states, specifically whether user benefits are worth highway agency costs to repair damage caused by studded tires. For example the Alaska Department of Transportation and Public Facilities (DOT&PF) estimates highway damage from studded-tire use in Alaska to be $5 million annually (D. Esch, unpublished data). The Oregon Department of Transportation (ODOT) recently published a preliminary report (2) that estimates studded-tire damage for 1993 to be $24 million on the state highway system and $18 million on city and county roads, for a total of $42 million in damage statewide. This new ODOT estimate increased by an order of magnitude previous estimates of pavement damage from studded tires. Clearly, there is renewed interest in Oregon to accurately determine the rate of pavement wear from studded tires and whether perceived safety benefits outweigh annual highway damage. BACKGROUND Studded tires were first authorized in Oregon in 1967 (3). Within a few years, excessive pavement wear became apparent. This led to a 64 TRANSPORTATION RESEA...