Current Asphalt Rubber Developments in Alberta

Asphalt rubber involves the use of rubber crumb from recycled tires in various hot-mix pavement and seal applications. The use of asphalt rubber has been around for over 50 years, yet its supported use in North America tends to be concentrated in a small number of U.S. states. The U.S. ISTEA legislation in 1991 led to the requirement for evaluating rubber in asphalt applications as a condition for federal funding. Although that U.S. legislation was repealed it did result in numerous trial sections throughout the U.S. which are now reaching an age where performance can be evaluated and the experience used to more closely consider life cycle costs. The use of asphalt-rubber in Canada has typically been trial sections, which have not performed adequately to provide the needed incentive to make asphalt rubber a mainstream product. In 2001 the Tire Recycling Management Association of Alberta (TRMA) and Alberta Transportation established a steering committee to once again examine the potential for using asphalt rubber in pavements in Alberta. Alberta Transportation and the Tire Recycling Management Association of Alberta, in conjunction with the cities of Calgary and Edmonton and Strathcona County, initiated a project to look at the feasibility of adopting asphalt rubber pavement technology in Alberta. Asphalt rubber has been used successfully in numerous states including Arizona, California, Texas and Florida in highway and street pavement rehabilitation for several decades. Four asphalt rubber trial sections were successfully constructed in Alberta in 2002 using the technology as currently used in Arizona. This paper provides a brief overview of the various methods used to incorporate recycled tire rubber into asphalt concrete pavements and seals and a short synopsis of the experience of agencies with the asphalt rubber wet process in pavement applications. Processes which used crumb-rubber as a part of the aggregate are described. Additionally, a summary of the current methods considered the most successful and a review of current Alberta work is presented Work undertaken in 2002 in Alberta includes the construction of four trial projects in four different road jurisdictions. This paper describes the phases and factors that contributed to the completion of the Alberta trial projects.