Bituminous surface treatment and its effectiveness as a municipal road surface—Faro, Yukon

• Published in: Canadian Journal of Civil Engineering
• Main Author: Cotterill, Robert
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1984
• Subjects: General Environmental Science; Civil and Structural Engineering; Yukon; Canada; Faro; Whitehorse; Alaska
• Online Access: http://dx.doi.org/10.1139/l84-007; http://www.nrcresearchpress.com/doi/pdf/10.1139/l84-007

The use of bituminous surface treatment (BST) as a road surface is a technique commonly accepted and understood by most provincial and territorial highways departments, but for the average engineer or municipality, it may be nothing more than the squirting of some oil on a road surface and covering this oil with some gravel.The topic of BST construction brings with it many different approaches, applications, and techniques. In the Yukon, Alaska, and western Canada, the two basic techniques used are: rapid setting emulsions and chip aggregates or high float emulsions and well-graded aggregates.Before the right approach is arrived at, an analysis of the expected traffic volumes, the condition of the sub-base, the quality and quantity of aggregate available, the types of emulsions available, and the cost of installing either of the techniques should be undertaken.In 1981, the town of Faro hired a local Whitehorse contractor to single surface treat 4.5 km of local roads, the final result being a combination of pot holes, ravelling, and streaking. A detailed investigation was undertaken to determine why the problems were experienced and to ascertain whether BST should be used on municipal streets in the future.The research indicated that the general design principles were correct but that an overabundance of gravel being specified, coupled with numerous errors in construction, produced an inferior product.A second treatment of approximately 1.5 km of road was undertaken in 1982 by a more experienced applicator, namely, the Yukon Government Highways forces, and many of the problems experienced in 1981 were overcome.The purpose of this paper is to present both the problems experienced in Faro and what approaches, applications, and techniques should be followed to minimize the possibility of these problems occurring in the future. Key words: aggregate, asphalt emulsion, tack coat, sub-base, bituminous, soil cement, streaking, pneumatic.