A study was conducted for the Texas Department of Transportation(DOT) by the Texas Transportation Institute (TTI) to address the following issues: (a) the current extent of use of asphalt rubber by the department, (b) the availability of crumb rubber produced from scrap tires and the availability of asphalt rubber in the state of Texas, and (c) the cost-effectiveness of asphalt rubber compared with conventional paving materials on the basis of existing information and the experience of department personnel. Published information was reviewed, phone interviews with knowledgeable department personnel were conducted, and existing laboratory information was evaluated. The Texas DOT currently uses asphalt rubber in four different applications. Listed in order of their volume of asphalt rubber consumption, these are: (a) chip seal or stress-absorbing membrane (SAM) construction, (b) stress-absorbing membrane interlayer (SAMI) construction, (c) crack or joint sealing, and (d) hot-mixed asphalt concrete pavement construction (on a very limited experimental basis). These applications of asphalt rubber are described in detail in the body of this paper. Results of this study indicated that the major obstacle for widespread use of asphalt rubber in Texas is its high cost.
Abstract