Description
The Nevada Department of Transportation (NDOT) constructed several crumb rubber modified (CRM) asphalt projects during the early 1990’s. Some of the projects were constructed in the region of hot weather while others were constructed in the region of cold weather. The CRM mixtures were designed following normal design procedures recommended by the asphalt rubber industry. On most cases the mix designs were developed by the contractor. NDOT and the Western Region Superpave Center monitored the long term performance of the various projects since their construction.
The long term performance of these projects showed that CRM mixtures used with reduced thickness are not effective under Nevada’s materials, traffic, environmental, and pavement conditions. In order for CRM mixtures to be effective under Nevada’s conditions, they must be built with a thickness equivalent to the conventional HMA mixtures which makes them too expensive to be considered as a rehabilitation alternative for flexible pavements in Nevada.
