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36 a. BOMAG Asphalt Manager IC Roller b. AMMANN IC Roller c. Caterpillar IC Roller d. Vibratory Roller Instrumented by TTI for Use on Research Projects Figure 16. Fully equipped rollers measuring the stiffness of the material being compacted. into account more than the Asphalt Manager does in an auto- formity of the mat, and results in accurate, consistent readings. mated fashion. The computer in the ACE system is capable of For impact on the contractor's progress, assuming that the receiving information such as lift thickness, number of passes, roller-mounted devices do what is claimed, they can help mix or soil type, which is used in the calculation of the mate- the contractor's progress and provide information so that the rial's stiffness or modulus. Just as with the Asphalt Manager, contractor can make better decisions in real-time regarding the system is fully integrated into a vibratory roller that is part compaction of pavement layers. of an operational paving train. 1.8 Summary of Process Impact 1.7.3 Summary Table 13 provides a summary of process impact on flexible The true test of this "intelligent compaction" system is pavement construction for different NDT technologies and whether it actually saves time (fewer passes), improves uni- devices regarding their use in QA programs.

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37 Table 13. Process impact of different NDT technologies and devices on QA programs. NDT Technologies Impact Deflection-Based DCP Non-Nuclear Devices Steady- Topics or Ultrasonic Non- State GPR Roller- Issues Gauges Trailer Portable Manual Automated Roller- Vibratory Mounted Mounted Easily used to develop HMA- density or No Yes No Yes No No No Yes Yes modulus Unbound- growth Yes curves? Deflection Penetration Penetration Density Stiffness Resulting Seismic Elastic Dielectric Deflection & Elastic Rate or Rate or & Water or Value Modulus Modulus Values Modulus Index Index Content Density Conversion required to Yes No No No No No Yes No No adjust readings? Requires calibration to specific Yes Yes Yes Yes Yes Yes Yes Yes No materials or soils? Can readily test thin Yes No No No Yes Yes Yes Yes Yes layers (<3 in.) Can readily test thick Yes No Yes Yes Yes Yes Yes No No layers (>12 in.) Readily applicable Yes Yes No Yes Yes Yes No Yes Yes to control? Readily applicable No, only Yes Yes final Yes Yes Yes Yes Yes No to acceptance? structure Additional auxiliary Yes, tow Yes, No No No No Yes No No equipment vehicle vehicle needed? Additional staff No No Yes, No No No No Yes Yes needed? operator Equipment readily available on Yes Yes Yes Yes Yes Yes Yes Yes Yes commercial basis? Software readily available on Yes NA Yes Yes NA NA No; for NA NA commercial Proprietary basis?