Full-Depth In-Place Recycling and Road Strengthening Systems for Low-Volume Roads: Highway No. 19 Case Study

Abstract

The province of Saskatchewan has the highest number of public roads per capita in Canada, totaling approximately 198,700 km. The Saskatchewan Department of Highways and Transportation manages approximately 26,100 km of these public roads. As with most public road agencies, the department has limited resources for managing this relatively large network of low-volume roads and therefore continually strives to research and implement more cost-effective and technically feasible solutions. Of particular concern are approximately 7,500 km of thin membrane surface (TMS) roads that are undergoing accelerated damage as truck traffic and loading increase. Although conventional TMS upgrading strategies are normally effective, there are potentially significant benefits to be gained with implementation of more cost-effective methods of road strengthening. Systems include granular soil strengthening and applications of different cement products, lime, various grades of fly ash, geotextiles, geogrids, natural and manufactured fibers, emulsified bitumen, tall oil, lignin, foamed bitumen, and synthetic ionic and cationic chemicals. Since 1999, in conjunction with Pavement Scientific International and in cooperation with the University of Saskatchewan and product suppliers, the department has constructed pilot projects on Highway No. 19 to identify, develop, and implement more cost-effective strengthening systems. The primary research objective is to investigate alternative road construction systems that will improve the load-carrying capacity and environmental durability of Saskatchewan TMS roads. Improved mechanistic engineering methods played a part in this initiative, and pilot project performance was monitored.