1. Rick Collins (TxDOT)

2.  Historically segregation thought of as mechanical (gradation) phenomenon  1996 – WSDOT discovered thermal imaging could detect segregation  Cold spots became low density areas  89 percent of locations with t > 25 F failed density uniformity criteria. Thermally segregated locations holding water (courtesy WSDOT)

3.  NCAT (2000) and TTI (2002) similarly found thermal uniformity suitable for detecting segregation  NCAT – low severity segregation when t > 18 F  TTI – when t > 25 F, TxDOT density uniformity requirements not met

4.  Existing methods using handheld IR devices already in place  Pave-IR system developed through research collects full- coverage testing without operator attendance

5.  Moba Corporation refined and now manufactures Pave-IR. This device is commercially available  Thermal profile and results available real time  Desktop software for viewing data files and generating pdf report Thermal Profile View in Operacion Summary Results in Operacion Reviewing Thermal Profile with Desktop Software

6.  In 2010 the use of Pave- IR is now included in TxDOT Special Provision 341-024  Pave-IR automatically processes data and generates report  Currently 12 Pave-IR systems purchased by Contractors and in use in Texas

7.  Sends pulses into pavement – non contact and high speed  Reflections obtained at interfaces of materials with different electrical (dielectric) properties  Traditionally used for thickness estimates and locating subsurface defects and section changes

8.  TxDOT has extensive experience using GPR and an active GPR program  In-house software for data processing  The amplitude of the Surface reflection is related to density of the HMA surface layer

9. Plan Profile View of expected Air Void Distribution

10.  IR serves well as QC with real-time monitoring  GPR serves as a QA check on completed projects IR Bar Installed in a Paver GPR Collecting Data