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The purpose of roads in areas of seasonal frost is to attenuate frost penetration and thus permit the design pavement thickness to be reduced. Early indications from actual use are that polystyrene insulation will meet these requirements. Two 100-ft (32.8-m) sections of street were constructed in Sudbury, Ontario, Canada, in September 1964 using 2-by-4-ft by 2-in. (0.610-by l.220-m by 5.08-cm) sheets of extruded polystyrene insulation in the pavement structure at a depth of 16 in. (0.406 m). In the summer of 1965 two additional insulated road sections were constructed in Ottawa, Ontario, Canada. Two types of insulation and methods were used. Extruded polystyrene boards were placed by hand (the same as at Sudbury) at the desired elevation. Polyurethane was foamed in place by spraying the chemicals on the road bed with a specially constructed self-propelled spraying machine. This paper discusses the relative merits of the different methods of roads and, in a broader context, the protection against freezing of underground utilities, such as water mains and sewers.

This paper is a report of a cooperative research program carried out in 1958 and 1959 by the National Research Council, Canada, and the Ontario Department of Highways to study the performance of some existing roads over muskeg in northern Ontario. Investigation of close to 50 different muskeg areas included classification of the muskeg, determination of the depth and type of fill, depth of the organic deposit, and type of mineral soil substratum. Roads over the muskeg areas were assessed on the basis of performance and surface condition relative to adjacent sections of road on mineral soil terrain. Many peat samples were obtained for laboratory analyses, which included water content, specific gravity, acidity, and ash content. During the second stage of the project an extensive series of field vane tests was carried out in certain selected muskeg areas that were typical for a certain region. Three different sizes of vanes were used. It is shown that road performance is better in muskeg areas with tall tree growth than in areas with little or no tree growth, other factors being equal. No correlation was evident between road condition and type of firm mineral soil substratum. However, an intermediate unstable layer of soft mineral soil is shown to be an important factor in road performance and condition. Although vane testing appears to be a feasible method for determining the shear strength of peat and excellent duplication of results was possible for any particular size of vane, these tests revealed a marked variation in the shear results depending on the vane size. Laboratory test results indicate correlations between moisture content and depth, specific gravity and moisture content, and acidity and carbon content., Reprint from: Highway Research Board Bulletin no. 316, 1962, p. 32-43.