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37 Ultrasonic Tomography Testing at NCAT Pavement Test Track This chapter was prepared by Kyle Hoegh, graduate research assistant, and Dr. Lev Khazanovich both at the University of Minnesota. Introduction This chapter summarizes the initial results of testing with an ultrasound tomography device (MIRA) at the NCAT Pave- ment Test Track (NPTT) in Opelika, Alabama. Testing was conducted on the morning of April 11, 2010, at 10 sections in the passing lane. Ultrasonic measurements were taken to locate the presence and extent of delamination, or the extent of delamination, at two-lift asphalt test sections. MIRA showed various consistent types of signals throughout the different sections. An initial diagnosis is presented in this chapter, including analysis of the intensity-based real-time Synthetic Aperture Focusing Technique SAFT signals as well as sub- sequent SAFT-Full Waveform (SAFT-FW) analysis. This analysis and the conclusions presented are preliminary, while disclosure of the constructed defect locations and forensic analysis can be used to verify or calibrate the actual diagnosis associated with the different types of signals. The use of SAFT B-scans and D-scans, as well as SAFT-FW B-Scans, indicated the following bond conditions based on an initial analysis: ⢠Section 1 is a proper bond between the asphalt lifts. ⢠Section 2 is delamination between asphalt lifts. ⢠Section 4 is slight level of delamination. ⢠Section 5 is significant level of delamination. ⢠Section 6 is very slight delamination. ⢠Sections 3, 7, 8, 9, and 10 are inconclusive when using the current analysis method. ⢠Newly constructed asphalt debonded with asphalt base in the right wheelpaths (RWPs) and left wheelpaths (LWPs) of Sections 9 and 10 as well as in the beginning (190 ft to 200 ft) of the LWP in Section 8. Testing An ongoing SHRP 2 NCAT Pavement Delamination Project was initiated to investigate nondestructive methods of deter- mining delamination between asphalt layers. The principal investigators of the project provided the testing layout where the ultrasonic tomography scans described below were carried out to determine the effectiveness of ultrasonic tomography in detection of delamination in asphalt. An ultrasonic tomogra- phy device, MIRA, was used to conduct a âblind testâ of loca- tions with various levels of fabricated distresses in the passing lane of the NPTT (see Figure 5.1). Each approximately 1-s MIRA scan gives a 2-dimensional (2-D) depth cross section (SAFT B-scan) with the vertical axis indicating the depth of any reflection (caused by any change in acoustic impedance), and the horizontal axis indicating the location along the aperture of the device with 0 being the center of the scan location. Figure 5.2 shows the MIRA device in position to take a SAFT B-scan. The type of SAFT B-scan signal that should be expected from properly bonded two-lift asphalt on an aggregate base is shown in Figure 5.3. This example B-scan was taken in the Section 6 truck lane and indicates a reflection at the asphalt-aggregate base inter- face of approximately 150 mm in depth. It can be observed that even in this properly bonded case, there is low-intensity reflection at shallower depths most likely due to reflections from aggregates and air voids. It is important to note that this amount of shallower reflection should be expected as a baseline for properly bonded cases when considering the delamination analysis. Auburn University personnel identified the general area where testing was needed to verify the capabilities of MIRA in delamination diagnostics (see Figure 5.4 for the approximate measurement zero point). The tested pavement was separated into ten 25-ft. sections for a total of 250 ft of scanning, with Section 1 starting at 15 ft in the longitudinal direction. MIRA scanning was conducted at various locations of the passing C h a p T e r 5
38 lane. MIRA scans were taken with the long portion of the device aperture in transverse and longitudinal orientations at various positions within the 250-ft passing lane section, as described below: ⢠Longitudinal orientation (see Figure 5.2a): Scan is taken with the long portion of the MIRA device parallel with the direction of traffic. In this orientation, the horizontal axis indicates the longitudinal location, with 0 being at the cen- ter of the scan location. ⢠Transverse orientation (see Figure 5.2b): Scan is taken with the long portion of the MIRA device perpendicular to the direction of traffic. In this orientation, the horizontal axis indicates the transverse location, with 0 being at the center of the scan location. Initial analysis Bands of measurements were taken in small step sizes (3 to 6 in.) in the transverse direction, with MIRA oriented longi- tudinally. By stitching these scans together, a profile below the surface in the transverse direction (TV) along the lane width (D-scan_TV) was realized. Similarly, bands of measurements taken in the transverse orientation with multiple small step sizes (~1 ft) in the longitudinal direction were stitched together to give a profile below the surface in both the right and left wheelpaths (D-scan_RWP and D-scan_LWP, respec- tively). These D-scans give an initial diagnosis of the amount of reflection occurring at different depths throughout the scanned section by averaging the intensity of reflection across the aperture of the device. The D-scans taken at each scanned location can be observed in Chapter 7. As mentioned in the description of the B-scan in Fig- ure 5.4, even in the case of properly bonded asphalt on grade, there are some lower intensity reflections at shallower depth due to aggregate and air voids. In addition, separat- ing reflections from the transmitted shear wave from surface wave interference is less coherent near the surface (within 3 in. depth). Because the depth of the interface in question is near this shallower depth, analyzing the direct reflection from the asphalt lift interface is a challenging problem. Real- time analysis of intensity based SAFT B-scans or D-scans is highly dependent on the threshold and gain and insufficient for analysis of direct reflection at this depth without further signal processing. Therefore, use of backwall reflections (reflection at the depth of the newly constructed asphalt Figure 5.3. Example scan indicating properly bonded asphalt on grade. D ire ct io n of tr af fic (a) (b) Figure 5.2. Ultrasonic tomography device (MIRA) in (a) longitudinal and (b) transverse orientations set for transverse and longitudinal step sizes, respectively. Passing Lane Testing Figure 5.1. NPTT blind test location. Passing Lane RWP LWP Oâ point Figure 5.4. Approximate longitudinal zero point location for MIRA testing.
39 section) is valuable for diagnosis. In this case, the D-scan initial analysis of delamination can be based on the clarity of the backwall reflection. When this type of indirect analysis is used, a clear backwall reflection at the depth of the newly constructed asphalt would indicate properly bonded asphalt lifts. A less intense, less coherent backwall reflection, or the lack of a backwall reflection, would indicate locations where there is some sort of delamination or other flaw within the constructed asphalt layers that could be caused by debonding at the asphalt lift interface. The type of analysis detailed above is effective for analysis where there is a consistent backwall reflection at the asphalt thickness depth. Therefore, cases where the asphalt is con- structed over a concrete or aggregate base allow for the analy- sis method described in the previous paragraph because there is a large enough difference in acoustic impedance to cause a consistent backwall reflection as a reference. For the asphalt sections tested at the NPTT, this type of analysis was only effective for diagnosing delamination conditions in Sections 1 and 2 because those sections were located on top of concrete, while the remaining sections were constructed on top of existing asphalt. Figure 5.5 shows the left and right wheelpath D-scans for Section 1. It can be observed that similar types of signals were found in the left and right wheelpaths, indicat- ing similar bond condition throughout the width of the lane. Section 1 scan locations showed a strong backwall reflec- tion, indicating properly bonded asphalt layers. It can also be observed that the backwall reflection is less coherent with less intensity from approximately 40 to 50 ft where Section 2 starts (the full Section 2 D-scans can be observed in Chapter 7). This is most likely due to shadowing of the backwall from delamination or defects in the constructed asphalt. While the analysis described above should be effective for getting an initial idea of the condition of the bond condition between lifts, the analysis is based only on reflection inten- sity. Additional information is available through analysis of the full waveform (including polarity of the reflected shear wave pulse). To use this additional information, a varia- tion of the SAFT algorithm that uses the full waveform was applied. This was carried out with the SAFT-FW algorithm developed at the University of Minnesota, which accounts for the polarity of the reflected wave pulses. Figure 5.6 gives an example scan location from Section 1 (Figures 5.6A and 5.6B) taken approximately at stationing 00+19 ft and Section 2 (Figures 5.6C and 5.6D) taken at approximately 00+42 ft. Similar to the D-scan analysis, the SAFT B-scans shown on the left (Figures 5.6A and 5.6D) have a stronger, more coher- ent backwall reflection in Section 1 as compared to Section 2. Using SAFT-FW scans (Figures 5.6B and 5.6D) adds addi- tional insight. It can be observed that the initial negative polarity (blue) arrival (indicative of a reflection from lower to higher impedance mediums) at the backwall reflection is nonexistent in the SAFT-FW scan of Section 2 (Figure 5.6D), while it is clear in the SAFT-FW scan of Section 1 (Figure 5.6B). Additional analysis of Figure 5.6D shows multiple reflections at smaller intervals than should be expected from a secondary backwall reflection, also indicating the presence of a shallower planar defect consistent with what should be expected from delamination at the asphalt lift. These types of comparisons were also observed in additional SAFT-FW B-scans as seen in Chapter 7. As described above, analysis of asphalt over an asphalt base requires more detailed analysis that does not rely on (a) Section 1 SAFT ~19 ft (b) Section 1 SAFT-FW ~19 ft (c) Section 2 SAFT ~42 ft (d) Section 2 SAFT-FW ~42 ft Figure 5.6. SAFT and SAFT-FW B-scans for representative locations of Section 1 (a and b, respectively) and Section 2 (c and d, respectively). Figure 5.5. Analysis of MIRA D-scans in the left and right wheelpaths of Section 1 and in the start of Section 2 for asphalt over a concrete base.
40 shadowing of the backwall reflection. In this case, if the con- structed layer and asphalt base are properly constructed, the backwall reflection will be absent. If there is debonding of the constructed asphalt layer and asphalt base, the backwall reflection should be present. Both of these processes are inde- pendent of the asphalt lift bond condition, therefore mak- ing analysis of the backwall reflection inconclusive when simple reflection intensity analysis is used. Figure 5.7 shows a D-scan taken along the transverse direction in the passing lane at about 242 ft in Section 10. It can be observed that there is a coherent backwall reflection at the start of the D-scan (in the LWP), then again at approximately two-thirds of the transverse D-scan. It is likely that this type of observation was caused by a poor bond between the constructed asphalt and asphalt base at locations where there is a backwall reflection. While this type of analysis is of little help in examining the asphalt lift bond condition, it did indicate that an improper bond at the asphalt thickness was likely in the LWP and RWP of Sections 9 and 10, as well as in the LWP at the start of Section 8. See Chapter 7 for more indications of debonding between the newly constructed asphalt and the asphalt base. For the other cases where a backwall reflection is largely absent (scans taken in Sections 3 through 7 and most scans taken in Section 8), each B-scan would need to be normalized so that reflections from any possible planar defect could be resolved from the structural noise and surface reflections. Through SAFT-FW normalization and analysis, character- istics of a shallow planar flaw were observed in certain loca- tions. Figure 5.8 shows an SAFT B-scan (Figure 5.8A) and an SAFT-FW B-scan (Figure 5.8B) taken in Section 5, as well as the same scans shown in Figure 5.6 (Figures 5.8C and 5.8D) from Section 2. Although analysis of the SAFT B-scans does not show any similarity between Section 5 and Section 2, a similar trend was observed in the SAFT-FW B-scans (Fig- ures 5.8B and 5.8D, respectively). While reflections at greater depths could not be resolved in Figure 5.8A, SAFT-FW analy- sis indicated multiple reflections at smaller intervals similar to those observed in Section 2 (Figure 5.8D), suggesting the presence of a shallower planar defect. This type of signal was consistently observed in Section 5, indicating the presence of delamination (see Chapter 7). Although less coherent and less frequent, signals that were similar were observed in Section 4, also indicating the presence of slight delamination at the lift (see Chapter 7). Some even less significant and less frequent similar type of signals were observed in Section 6, indicating very slight delamination at the lift. Further investigation of scans at Sections 3, 7, and 8 would be required to determine the presence or extent of delamination, because the methods presented in this chapter did not show a strong or consistent indication of delamination. Conclusions Testing with an ultrasound tomography device (MIRA) at the NPTT in Opelika, Alabama, based on intensity of reflection B-scan and D-scan results showed different types of signals. The similarities between the left and right wheelpaths and coherent changes in their D-scans indicated multiple consistent trends in the asphalt conditions within most sections. The SAFT-FW algorithm was also used to give additional information about the asphalt condition in which real-time SAFT analysis needed further investigation. The results that follow are preliminary and are given on the basis of the current MIRA analysis. Analysis of bond condition of asphalt lifts at 3 in. or less for asphalt constructed on a concrete or aggregate base is more straightforward than analysis for an asphalt base. However, initial analysis of asphalt constructed on asphalt base shows that delamination at greater depths can be observed by ana- lyzing the direct reflection from MIRA SAFT B-scans. (a) Section 5 SAFT-FW ~135 ft (b) Section 5 SAFT-FW ~135 ft (c) Section 1 SAFT ~42 ft (d) Section 1 SAFT-FW ~42 ft Figure 5.8. Sections 5 (top) and 2 (bottom) SAFT B-scans ( left) and SAFT-FW B-scans (right). Figure 5.7. D-scan-TV taken along the transverse direction in the passing lane at about 242 ft in Section 10.
41 Analysis using SAFT-FW allows for a more comprehensive analysis of bond condition of asphalt over a concrete base and also seems to give an indication of severe lift debonding, even for cases where the newly constructed asphalt is fully bonded to the asphalt base. The use of SAFT B-scans and D-scans, as well as SAFT-FW B-scans, indicated the following bond conditions: ⢠Concrete base (Sections 1 and 2): 4 Section 1: Strong backwall reflection, indicating a proper bond between the asphalt lifts. 4 Section 2: Shadowing of backwall reflection in SAFT B-scans and D-scans, as well as multiple reflections at small depth intervals, indicating a significant level of delamination between asphalt lifts in Section 2. ⢠Asphalt base (Sections 3 through 10): 4 Bond between newly constructed asphalt and asphalt base. 4 Sections 3, 4, 5, 6, and 7: Absence of significant back- wall reflection in D-scans and B-scans, indicating good bond between the newly constructed asphalt and the old asphalt. 4 Section 8: Backwall reflection in the LWP from 190 ft to 200 ft indicating debonding in LWP at the beginning of the section. Absence of significant backwall reflection in RWP and transverse direction at 192 ft, indicating good bond between the newly constructed asphalt and the old asphalt in those locations. 4 Sections 9 and 10: Backwall reflection from 225 ft to 250 ft in the RWP and LWP in the longitudinal D-scans as well as at the beginning and at the two-thirds mark of the Section 10 transverse D-scans, indicating debonding in both wheelpaths. No backwall reflection in the major- ity of the transverse direction D-scans, indicating proper bond in locations not located near the wheel paths. Bond between asphalt lifts in the newly constructed asphalt. 4 Section 4: SAFT-FW analysis shows a less coherent and less consistent amount of multiple reflections at small depth intervals, indicating a small level of delamination. 4 Section 5: SAFT-FW analysis shows multiple reflections at small depth intervals, indicating a significant level of delamination. 4 Section 6: Although less coherent than in Section 4, an SAFT-FW analysis shows slight multiple reflections at some locations, indicating very slight delamination. 4 Sections 3, 7, 8, 9, and 10: Little to no indication of mul- tiple reflections in SAFT-FW analysis, indicating either no presence of delamination, or a need for a detailed analysis method for shallow-lift delamination detection of asphalt constructed on an asphalt base. Section 1 131.54mm 25.00us offset 2.01 mm/us128.46mm 25.00us offset 2.01 mm/us130.77mm 25.00us offset 2.01 mm/us135.38mm 25.00us offset 2.01 mm/us140.00mm 25.00us offset 2.01 mm/us 136.15mm 25.00us offset 2.01 mm/us135.38mm 25.00us offset 2.01 mm/us135.38mm 25.00us offset 2.01 mm/us135.38mm 25.00us offset 2.01 mm/us133.08mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 1 into 0 Left Wheel Path Figure 5.10. SAFT-FW B-scans taken from Position 1 (~25 ft) to Position 10 (~15 ft) in the LWP. Figure 5.9. Left (top) and right (bottom) wheelpath D-scans with horizontal axis indicating longitudinal stationing and vertical axis indicating depth below the measurement.
42 138.46mm 25.00us offset 2.01 mm/us138.46mm 25.00us offset 2.01 mm/us137.69mm 25.00us offset 2.01 mm/us136.92mm 25.00us offset 2.01 mm/us135.38mm 25.00us offset 2.01 mm/us 134.62mm 25.00us offset 2.01 mm/us136.15mm 25.00us offset 2.01 mm/us133.08mm 25.00us offset 2.01 mm/us131.54mm 25.00us offset 2.01 mm/us130.00mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 1 Transverse Measurement (17' - 30 khz) Figure 5.13. SAFT-FW B-scans at a center frequency of 30 kHz taken from a location at 17 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Note: Thresh. = threshold. Figure 5.12. SAFT D-scan ( left ) taken at the beginning of Section 1 along the transverse direction along with an example SAFT and SAFT-FW B-scan at Position 6 (right ). 97.69 mm 25.00us offset 2.01 mm/us130.00mm 25.00us offset 2.01 mm/us131.54mm 25.00us offset 2.01 mm/us130.00mm 25.00us offset 2.01 mm/us130.00mm 25.00us offset 2.01 mm/us 131.54mm 25.00us offset 2.01 mm/us133.08mm 25.00us offset 2.01 mm/us137.69mm 25.00us offset 2.01 mm/us133.08mm 25.00us offset 2.01 mm/us135.38mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 1 into 0 Right Wheel Path Figure 5.11. SAFT-FW B-scans taken from Position 1 (~25 ft) to Position 10 (~13 ft) in the RWP.
43 129.23mm 25.00us offset 2.01 mm/us 130.00mm 25.00us offset 2.01 mm/us130.77mm 25.00us offset 2.01 mm/us130.00mm 25.00us offset 2.01 mm/us129.23mm 25.00us offset 2.01 mm/us 126.92mm 25.00us offset 2.01 mm/us128.46mm 25.00us offset 2.01 mm/us125.38mm 25.00us offset 2.01 mm/us123.08mm 25.00us offset 2.01 mm/us123.85mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 1 Transverse Measurement (17' - 50 khz) Figure 5.14. SAFT-FW B-scans at a center frequency of 50 kHz taken from at 17 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Section 2 131.54mm 25.00us offset 2.01 mm/us136.15mm 25.00us offset 2.01 mm/us133.08mm 25.00us offset 2.01 mm/us136.15mm 25.00us offset 2.01 mm/us135.38mm 25.00us offset 2.01 mm/us 138.46mm 25.00us offset 2.01 mm/us131.54mm 25.00us offset 2.01 mm/us124.62mm 25.00us offset 2.01 mm/us127.69mm 25.00us offset 2.01 mm/us120.77mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 2 into 1 Left Wheel Path Figure 5.16. SAFT-FW B-scans taken from Position 1 (~50 ft) to Position 10 (~40 ft) in the LWP. Figure 5.15. Left (top) and right (bottom) wheelpath D-scans with horizontal axis indicating longitudinal stationing and vertical axis indicating depth below the measurement.
44 126.92mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us126.15mm 25.00us offset 2.01 mm/us128.46mm 25.00us offset 2.01 mm/us126.92mm 25.00us offset 2.01 mm/us 126.15mm 25.00us offset 2.01 mm/us257.69mm 25.00us offset 2.01 mm/us126.15mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us123.08mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 2 Transverse Measurement (42' - 30 khz) Figure 5.19. SAFT-FW B-scans at a center frequency of 30 kHz taken from a location at 42 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Note: Thresh. = threshold. Figure 5.18. SAFT D-scan ( left) taken at the beginning of Section 2 along the transverse direction along with an example SAFT and SAFT-FW B-scan at Position 22 (right ). 129.23mm 25.00us offset 2.01 mm/us126.92mm 25.00us offset 2.01 mm/us120.77mm 25.00us offset 2.01 mm/us114.62mm 25.00us offset 2.01 mm/us121.54mm 25.00us offset 2.01 mm/us 125.38mm 25.00us offset 2.01 mm/us118.46mm 25.00us offset 2.01 mm/us109.23mm 25.00us offset 2.01 mm/us107.69mm 25.00us offset 2.01 mm/us106.15mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 2 into 1 Right Wheel Path Figure 5.17. SAFT-FW B-scans taken from Position 1 (~50 ft) to Position 10 (~38 ft) in the RWP.
45 126.92mm 25.00us offset 2.01 mm/us65.38 mm 25.00us offset 2.01 mm/us67.69 mm 25.00us offset 2.01 mm/us75.38 mm 25.00us offset 2.01 mm/us119.23mm 25.00us offset 2.01 mm/us 119.23mm 25.00us offset 2.01 mm/us120.77mm 25.00us offset 2.01 mm/us120.77mm 25.00us offset 2.01 mm/us116.15mm 25.00us offset 2.01 mm/us242.31mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 2 Transverse Measurement (64' - 30 khz) Figure 5.22. SAFT-FW B-scans at a center frequency of 30 kHz taken from a location at 64 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Figure 5.21. SAFT D-scan ( left) taken at the end of Section 2 along the transverse direction along with an example SAFT and SAFT-FW B-scan at Position 18 (right ). 86.15 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us122.31mm 25.00us offset 2.01 mm/us123.08mm 25.00us offset 2.01 mm/us121.54mm 25.00us offset 2.01 mm/us 120.77mm 25.00us offset 2.01 mm/us121.54mm 25.00us offset 2.01 mm/us120.77mm 25.00us offset 2.01 mm/us120.77mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 2 Transverse Measurement (42' - 50 khz) Figure 5.20. SAFT-FW B-scans at a center frequency of 50 kHz taken from a location at 42 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane.
46 121.54mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us314.62mm 25.00us offset 2.01 mm/us67.69 mm 25.00us offset 2.01 mm/us116.92mm 25.00us offset 2.01 mm/us 110.77mm 25.00us offset 2.01 mm/us87.69 mm 25.00us offset 2.01 mm/us113.08mm 25.00us offset 2.01 mm/us113.08mm 25.00us offset 2.01 mm/us113.08mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 2 Transverse Measurement (64' - 50 khz) Figure 5.23. SAFT-FW B-scans at a center frequency of 50 kHz taken from a location at 64 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Section 3 98.46 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us 97.69 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 3 into 2 Left Wheel Path Figure 5.25. SAFT-FW B-scans taken from Position 1 (~75 ft) to Position 10 (~60 ft) in the LWP. Figure 5.24. Left (top) and right (bottom) wheelpath D-scans with horizontal axis indicating longitudinal stationing and vertical axis indicating depth below the measurement.
47 Section 4 50.77 mm 25.00us offset 2.01 mm/us67.69 mm 25.00us offset 2.01 mm/us65.38 mm 25.00us offset 2.01 mm/us92.31 mm 25.00us offset 2.01 mm/us92.31 mm 25.00us offset 2.01 mm/us 128.46mm 25.00us offset 2.01 mm/us130.77mm 25.00us offset 2.01 mm/us90.77 mm 25.00us offset 2.01 mm/us90.77 mm 25.00us offset 2.01 mm/us131.54mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 4 into 3 Left Wheel Path Figure 5.28. SAFT-FW B-scans taken from Position 1 (~100 ft) to Position 10 (~90 ft) in the LWP. Figure 5.27. Left (top) and right (bottom) wheelpath D-scans with horizontal axis indicating longitudinal stationing and vertical axis indicating depth below the measurement. 65.38 mm 25.00us offset 2.01 mm/us51.54 mm 25.00us offset 2.01 mm/us100.00mm 25.00us offset 2.01 mm/us100.77mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us 96.15 mm 25.00us offset 2.01 mm/us97.69 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us113.08mm 25.00us offset 2.01 mm/us97.69 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 3 into 2 Right Wheel Path Figure 5.26. SAFT-FW B-scans taken from Position 1 (~75 ft) to Position 10 (~58 ft) in the RWP.
48 90.77 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us333.85mm 25.00us offset 2.01 mm/us97.69 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us 97.69 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us97.69 mm 25.00us offset 2.01 mm/us97.69 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 4 Transverse Measurement (92' - 30 khz) Figure 5.31. SAFT-FW B-scans at a center frequency of 30 kHz taken from a location at 92 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Note: Thresh. = threshold. Figure 5.30. SAFT D-scan ( left) taken at the beginning of Section 4 along the transverse direction along with an example SAFT and SAFT-FW B-scan at Position 10 (right ). 93.85 mm 25.00us offset 2.01 mm/us96.15 mm 25.00us offset 2.01 mm/us113.08mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us100.77mm 25.00us offset 2.01 mm/us 67.69 mm 25.00us offset 2.01 mm/us97.69 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us97.69 mm 25.00us offset 2.01 mm/us100.77mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 4 into 3 Right Wheel Path Figure 5.29. SAFT-FW B-scans taken from Position 1 (~100 ft) to Position 10 (~88 ft) in the RWP.
49 Section 5 86.15 mm 25.00us offset 2.01 mm/us86.92 mm 25.00us offset 2.01 mm/us87.69 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us 89.23 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us86.92 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 4 Transverse Measurement (92' - 50 khz) Figure 5.32. SAFT-FW B-scans at a center frequency of 50 kHz taken from a location at 92 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. 94.62 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us99.23 mm 25.00us offset 2.01 mm/us96.15 mm 25.00us offset 2.01 mm/us 96.15 mm 25.00us offset 2.01 mm/us96.15 mm 25.00us offset 2.01 mm/us96.92 mm 25.00us offset 2.01 mm/us96.15 mm 25.00us offset 2.01 mm/us92.31 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 5 into 4 Left Wheel Path Figure 5.34. SAFT-FW B-scans taken from Position 1 (~125 ft) to Position 10 (~115 ft) in the LWP. Figure 5.33. Left (top) and right (bottom) wheelpath D-scans with horizontal axis indicating longitudinal stationing and vertical axis indicating depth below the measurement.
50 96.92 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us92.31 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us87.69 mm 25.00us offset 2.01 mm/us 94.62 mm 25.00us offset 2.01 mm/us65.38 mm 25.00us offset 2.01 mm/us67.69 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us67.69 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 5 Transverse Measurement (117' - 30 khz) Figure 5.37. SAFT-FW B-scans at a center frequency of 30 kHz taken from a location at 17 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Note: Thresh. = threshold. Figure 5.36. SAFT D-scan ( left) taken at the beginning of Section 5 along the transverse direction along with an example SAFT and SAFT-FW B-scan at Position 13 (right ). 96.15 mm 25.00us offset 2.01 mm/us100.00mm 25.00us offset 2.01 mm/us51.54 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us88.46 mm 25.00us offset 2.01 mm/us 92.31 mm 25.00us offset 2.01 mm/us90.77 mm 25.00us offset 2.01 mm/us92.31 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 5 into 4 Right Wheel Path Figure 5.35. SAFT-FW B-scans taken from Position 1 (~125 ft) to Position 10 (~113 ft) in the RWP.
51 88.46 mm 25.00us offset 2.01 mm/us87.69 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us 50.77 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 5 Transverse Measurement (117' - 50 khz) Figure 5.38. SAFT-FW B-scans at a center frequency of 50 kHz taken from a location at 17 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Section 6 94.62 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us97.69 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us 90.77 mm 25.00us offset 2.01 mm/us95.38 mm 25.00us offset 2.01 mm/us377.69mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us97.69 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 6 into 5 Left Wheel Path Figure 5.40. SAFT-FW B-scans taken from Position 1 (~150 ft) to Position 10 (~140 ft) in the LWP. Figure 5.39. Left (top) and right (bottom) wheelpath D-scans with horizontal axis indicating longitudinal stationing and vertical axis indicating depth below the measurement.
52 92.31 mm 25.00us offset 2.01 mm/us65.38 mm 25.00us offset 2.01 mm/us92.31 mm 25.00us offset 2.01 mm/us65.38 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us 94.62 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us67.69 mm 25.00us offset 2.01 mm/us95.38 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 6 Transverse Measurement (142' - 30 khz) Figure 5.43. SAFT-FW B-scans at a center frequency of 30 kHz taken from a location at 142 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. 98.46 mm 25.00us offset 2.01 mm/us117.69mm 25.00us offset 2.01 mm/us69.23 mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us102.31mm 25.00us offset 2.01 mm/us 82.31 mm 25.00us offset 2.01 mm/us75.38 mm 25.00us offset 2.01 mm/us70.00 mm 25.00us offset 2.01 mm/us82.31 mm 25.00us offset 2.01 mm/us82.31 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 6 into 5 Right Wheel Path Figure 5.41. SAFT-FW B-scans taken from Position 1 (~150 ft) to Position 10 (~138 ft) in the RWP. Figure 5.42. SAFT D-scan taken at the beginning of Section 6. Note: Thresh. = threshold.
53 86.15 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us87.69 mm 25.00us offset 2.01 mm/us87.69 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us 50.77 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us50.77 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 6 Transverse Measurement (142' - 50 khz) Figure 5.44. SAFT-FW B-scans at a center frequency of 50 kHz taken from a location at 142 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Section 7 97.69 mm 25.00us offset 2.01 mm/us 94.62 mm 25.00us offset 2.01 mm/us 96.15 mm 25.00us offset 2.01 mm/us 98.46 mm 25.00us offset 2.01 mm/us 98.46 mm 25.00us offset 2.01 mm/us 97.69 mm 25.00us offset 2.01 mm/us 92.31 mm 25.00us offset 2.01 mm/us 106.15mm 25.00us offset 2.01 mm/us 96.15 mm 25.00us offset 2.01 mm/us 97.69 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 7 into 6 Left Wheel Path Figure 5.46. SAFT-FW B-scans taken from Position 1 (~175 ft) to Position 10 (~165 ft) in the LWP. Figure 5.45. Left (top) and right (bottom) wheelpath D-scans with horizontal axis indicating longitudinal stationing and vertical axis indicating depth below the measurement.
54 97.69 mm 25.00us offset 2.01 mm/us 98.46 mm 25.00us offset 2.01 mm/us 98.46 mm 25.00us offset 2.01 mm/us 96.15 mm 25.00us offset 2.01 mm/us 94.62 mm 25.00us offset 2.01 mm/us 50.77 mm 25.00us offset 2.01 mm/us 65.38 mm 25.00us offset 2.01 mm/us 65.38 mm 25.00us offset 2.01 mm/us 98.46 mm 25.00us offset 2.01 mm/us 98.46 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 7 Transverse Measurement (167' - 30 khz) Figure 5.49. SAFT-FW B-scans at a center frequency of 30 kHz taken from a location at 17 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Note: Thresh. = threshold. Figure 5.48. SAFT D-scan taken at the beginning of Section 7 along the transverse direction. 92.31 mm 25.00us offset 2.01 mm/us 95.38 mm 25.00us offset 2.01 mm/us 94.62 mm 25.00us offset 2.01 mm/us 94.62 mm 25.00us offset 2.01 mm/us 94.62 mm 25.00us offset 2.01 mm/us 82.31 mm 25.00us offset 2.01 mm/us 101.54mm 25.00us offset 2.01 mm/us 70.00 mm 25.00us offset 2.01 mm/us 75.38 mm 25.00us offset 2.01 mm/us 82.31 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 7 into 6 Right Wheel Path Figure 5.47. SAFT-FW B-scans taken from Position 1 (~175 ft) to Position 10 (~163 ft) in the RWP.
55 87.69 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us87.69 mm 25.00us offset 2.01 mm/us87.69 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us 87.69 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us90.77 mm 25.00us offset 2.01 mm/us90.77 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 7 Transverse Measurement (167' - 50 khz) Figure 5.50. SAFT-FW B-scans at a center frequency of 50 kHz taken from a location at 17 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Section 8 135.38mm 25.00us offset 2.01 mm/us137.69mm 25.00us offset 2.01 mm/us136.15mm 25.00us offset 2.01 mm/us131.54mm 25.00us offset 2.01 mm/us133.85mm 25.00us offset 2.01 mm/us 133.08mm 25.00us offset 2.01 mm/us131.54mm 25.00us offset 2.01 mm/us298.46mm 25.00us offset 2.01 mm/us128.46mm 25.00us offset 2.01 mm/us125.38mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 8 into 7 Left Wheel Path Figure 5.52. SAFT-FW B-scans taken from Position 1 (~200 ft) to Position 10 (~190 ft) in the LWP. Figure 5.51. Left (top) and right (bottom) wheelpath D-scans with horizontal axis indicating longitudinal stationing and vertical axis indicating depth below the measurement.
56 96.15 mm 25.00us offset 2.01 mm/us96.92 mm 25.00us offset 2.01 mm/us96.15 mm 25.00us offset 2.01 mm/us96.15 mm 25.00us offset 2.01 mm/us95.38 mm 25.00us offset 2.01 mm/us 94.62 mm 25.00us offset 2.01 mm/us97.69 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us95.38 mm 25.00us offset 2.01 mm/us96.15 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 8 Transverse Measurement (192' - 30 khz) Figure 5.55. SAFT-FW B-scans at a center frequency of 30 kHz taken at a location 192 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Figure 5.54. SAFT D-scan taken at the beginning of Section 8 along the transverse direction. 95.38 mm 25.00us offset 2.01 mm/us 93.85 mm 25.00us offset 2.01 mm/us 92.31 mm 25.00us offset 2.01 mm/us 95.38 mm 25.00us offset 2.01 mm/us 98.46 mm 25.00us offset 2.01 mm/us 98.46 mm 25.00us offset 2.01 mm/us 94.62 mm 25.00us offset 2.01 mm/us 95.38 mm 25.00us offset 2.01 mm/us 97.69 mm 25.00us offset 2.01 mm/us 98.46 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 8 into 7 Right Wheel Path Figure 5.53. SAFT-FW B-scans taken from Position 1 (~200 ft) to Position 10 (~188 ft) in the RWP.
57 86.15 mm 25.00us offset 2.01 mm/us86.92 mm 25.00us offset 2.01 mm/us90.77 mm 25.00us offset 2.01 mm/us86.92 mm 25.00us offset 2.01 mm/us86.15 mm 25.00us offset 2.01 mm/us 87.69 mm 25.00us offset 2.01 mm/us87.69 mm 25.00us offset 2.01 mm/us89.23 mm 25.00us offset 2.01 mm/us87.69 mm 25.00us offset 2.01 mm/us90.77 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 8 Transverse Measurement (192' - 50 khz) Figure 5.56. SAFT-FW B-scans at a center frequency of 50 kHz taken at a location 192 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane. Section 9 Note: Thresh. = threshold. Figure 5.58. SAFT D-scan taken at the beginning of Section 9 along the transverse direction. Figure 5.57. Left (top) and right (bottom) wheelpath D-scans with horizontal axis indicating longitudinal stationing and vertical axis indicating depth below the measurement. Figure 5.59. Left (top) and right (bottom) wheelpath D-scans with horizontal axis indicating longitudinal stationing and vertical axis indicating depth below the measurement. Section 10
58 Figure 5.61. SAFT D-scan taken at the beginning of Section 10 along the transverse direction. Section 10 into 9 Right Wheel Path 92.31 mm 25.00us offset 2.01 mm/us92.31 mm 25.00us offset 2.01 mm/us92.31 mm 25.00us offset 2.01 mm/us142.31mm 25.00us offset 2.01 mm/us144.62mm 25.00us offset 2.01 mm/us 143.85mm 25.00us offset 2.01 mm/us98.46 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us95.38 mm 25.00us offset 2.01 mm/us94.62 mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Figure 5.60. SAFT-FW B-scans taken from Position 1 (~250 ft) to Position 10 (~240 ft) in the RWP. 141.54mm 25.00us offset 2.01 mm/us 143.85mm 25.00us offset 2.01 mm/us 139.23mm 25.00us offset 2.01 mm/us 138.46mm 25.00us offset 2.01 mm/us 92.31 mm 25.00us offset 2.01 mm/us 96.15 mm 25.00us offset 2.01 mm/us 96.92 mm 25.00us offset 2.01 mm/us 97.69 mm 25.00us offset 2.01 mm/us 98.46 mm 25.00us offset 2.01 mm/us 433.85mm 25.00us offset 2.01 mm/us position1 position2 position3 position4 position6 position7 position8 position9 position5 position10 Section 10 Transverse Measurement (242' 30 khz) Figure 5.62. SAFT-FW B-scans at a center frequency of 30 kHz taken from a location at 17 ft along the transverse direction starting at the LWP through a location just before the center of the passing lane.
