Note on structural strength of asphalt rubber concrete developed through the stone mastic asphalt concept
One serious environmental problem related to the transportation field is the stockpiling of old rubber tires. Several huge fires of old tires have already occurred in Canada and the United States and have caused considerable air and possibly soil pollution. Therefore it is of paramount importance to develop techniques to recycle this potentially valuable material, such as by incorporating it into asphalt concrete. The focus of current research at the Centre for Surface Transportation Technology has been to develop a high-performance rubber asphalt concrete based on the stone mastic asphalt (SMA) concept which will be flexible enough (yet strong enough) to resist differential frost heave along roadways better than standard hot-mixed asphalt. Results indicate that a special mix has been successfully developed based on the SMA aggregate concept in which all components, including 0%, 5%, 10%, 15%, and 20% of small rubber crumbs content (based on bitumen weight), are properly sized and designed. Key words: stone mastic asphalt, crumb rubber, laboratory testing, mix design.