Billy Connor

Poor air quality in Alaska’s remote communities due to road dust is one of the top environmental concerns of residents in these communities. Most communities are disconnected from the road network, with community roads that are predominantly unpaved. In Alaska, high costs limit widespread paving of roads, leaving communities to rely on alternative dust control strategies. The goals for this study were to assess the magnitude and impact of the dust problem in rural Alaska and use a diversity of experience, including regulatory, research, engineering, and cultural, to develop a road-dust management approach for rural Alaska. The plan incorporates different levels of dust management: institutional controls, road watering, chemical dust suppressants, and road surface stabilization. Geographical zones where use of each different dust management level will be most appropriate are identified based on rainfall frequency. Approximately 50% of Alaska’s communities can manage road dust with institutional controls and road watering. Many of the road-dust management ideas presented are transferable to other global regions that experience similar economic and community access challenges as Alaska.

A number of completed or ongoing studies on different aspects of warm-mix asphalt (WMA) have being conducted in the United States, indicating pavement professionals’ strong interest in exploring the application of this innovative technology. In the summer of 2008, a field trial project using Sasobit-modified WMA was established in the southeastern region of Alaska, which was Alaska’s first experience with a WMA technology. In line with this field experimental feature project, this paper presents a systematic laboratory study of both Sasobit-modified WMA binders and mixes. Engineering properties of Sasobit-modified WMA binders and mixes were experimentally evaluated, and the effects of Sasobit addition on the WMA’s performance in terms of low temperature behavior, rutting resistance, and moisture susceptibility were investigated. Research results identified a number of engineering benefits of Sasobit-modified WMAs over conventional HMA. Sasobit-modified WMAs reduced mixing and compaction temperatures, impr...

The construction of the Alaska Highway has been hailed as a major engineering project of the 20^th Century, a century of massive infrastructure development in the United States. The construction was completed in two phases: a pioneer road followed by the construction of an all weather road. While numerous text and film documentaries focus on the soldiers and construction workers and the hardships faced, the project hinged on the efforts of the surveyors and professional engineers who selected routes and designed the roadway without the benefit of detailed reconnaissance, soils data, and hydraulic information. Surveyors and engineers performed their tasks admirably in a hostile environment with the sound of bulldozers at their backs.

The Yukon River Bridge in interior Alaska is recognized as an outstanding civil engineering design. The structure is a six-span 884.4-m steel bridge on a 6 percent grade. Two 155.9-cm wide by 414.0-cm deep steel box girders support an orthotropic steel deck. The structure carries the oil pipeline, vehicles, tourism busses and heavy trucks. In addition to highway traffic and the oil pipeline, there is potential for the structure to carry a future gas line. Weather can vary from harsh winter temperatures combined with snow and ice to mild summer temperatures. This structure was designed in the early 70's with a temporary 127-mm two-layer timber deck-wearing surface. Since then, timber running planks have been replaced three times with similar timbers (1981, 1992, and 1999). In 1992, in addition to running planks, timber deck planks were replaced and the steel deck was cleaned and coated against corrosion. A successful wearing surface for this bridge must be cost effective, lightweight, abrasion resistant and provide traction; especially during winter months. A wearing surface selection criterion is discussed and wearing surfaces on similar bridges are examined. Two examples illustrate a design procedure for selecting a wearing surface on this structure; design charts are used. The design charts account for truckloads and temperature change. No charts are available for traction or abrasion.

Recently published research has proven the feasibility of the theory of using geosynthetic materials to reinforce unpaved roadways over thermokarst terrain that includes complete voids. The research developed the theory to design geosynthetic bridges, and full‐scale tests substantiated the theory. The present study consists of four additional field‐test sections studied over a period of two summers. As in the previous tests, the tests consisted of making a trench, placing a geosynthetic across it, and constructing a roadway section over the trench and geosynthetic. The trenches were wider than in previous tests; some of the trenches extended diagonally across the road and some of the test sections were paved. From these tests, criteria were developed to design paved roads over thermokarst terrain.

Geosynthetics can be used to support road embankments over voids. This report briefly summarizes a mathematical model developed to design such a system and presents the results of a series of field tests performed to verify the mathematical model. The theoretical model is easy to use, but it involves an iterative solution, so it is best suited to computer solution. Use of the mathematical model indicates that voids on the order of 3 m or more can be supported on commercially available geosynthetics. The field tests had voids up to 1.8 m wide. Performance of the embankment surface under traffic loading was basically the same over the voids and between the voids, indicating that paving the surface may be a viable option.