Many Texas Department of Transportation (TxDOT) districts across the state use tire rubber (TR) in asphalt binders on chip seal projects. Traditionally, the test procedure that determines whether the appropriate amount of TR is in the binder has only been performed in the TxDOT Materials and Tests Division lab, requiring a long time to complete. Researchers at University of Texas Center for Transportation Research developed a portable X-Ray Fluorescence (XRF) device that can test for binder TR levels in minutes, allowing the testing to occur in the district labs and even in the field. District personnel are being provided with the device and trained on its use.
For more information on research project 0-7168, check out the TxDOT Research Library project record here: 
library.ctr.utexas.edu/Presto...
For access to all TxDOT research, please visit the TxDOT Research Library at ctr.utexas.edu/library/