Mapping Voids, Debonding, Delaminations, Moisture, and Other Defects Behind or Within Tunnel Linings (2013)

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146 a p p e N D I x N Introduction This appendix summarizes the field evaluations of the non- destructive testing (NDT) technique known as ultrasonic tomography (UST). The tests were performed within the framework of the second Strategic Highway Research Program (SHRP 2) Renewal Project R06G. The objectives of this project have been listed in the Executive Summary of the main report. Thirty specimens with simulated defects were tested before the UST equipment was used in the field. Table N.1 summarizes those tests. Following are evaluation summaries of the test sites located at Eisenhower Memorial Tunnel near Dillon, Colorado; Hanging Lake Tunnel near Glenwood Springs, Colorado; Chesapeake Channel Tunnel near Norfolk, Virginia; Wash- burn Tunnel in Houston, Texas; continuously reinforced con- crete pavement on I-20 in Fort Worth, Texas; and bonded concrete overlays at the George Bush International Airport in Houston, Texas (Figures N.1–N.56). Ultrasonic Tomography Test Summaries

147 Table N.1. Detailed Defect Dimensions, Depth, and Cover and Spacing (in.) Specimen Name and Material Actual Reinforcement Cover and Spacing Measured Reinforcement Cover and Spacing Type of Defect Actual Dimensions of Defect Actual Depth of Defect Measured Dimensions of Defect Measured Depth of Defect Actual Specimen Depth Measured Specimen Depth Alpha, concrete None na None na na na na 12 12.4 Beta, concrete a 4.0 at 8.0 on center None na na na na 18 17.6 Gamma, concrete a 4.3 at 7.9 on center None na na na na 12 11.7 Delta, concrete None na None na na na na 24 23.6 Epsilon, concrete a 4.1 at 8.0 on center None na na na na 24 23.3 Zeta, concrete a 3.8 at 7.9 on center None na na na na 15 14.1 Eta, concrete a 4.5 at 7.9 on center plastic 12 by 12 by 1 2 11.7 by 12.8 2.3 15 14.2 Theta, concrete a 4.4 at 8.0 on center plastic 12 by 12 by 1 3 11.7 by 13.5 3.5 15 13.9 Iota, concrete a 4.0 at 8.0 on center plastic 12 by 12 by 1 1 7.8 by 12.3 1.7 15 13.0 Kappa, concrete a 3.8 at 8.0 on center Styrofoam 12 by 12 by 1 8 15.7 by 15.7 8.0 15 14.7 Lambda, concrete a 3.7 at 8.1 on center Water-filled void 12 by 12 8 16.5 by 15.4 6.5–8.8 15 14.6 A, shotcrete None na None na na na na 4 3.9 B, shotcrete None na None na na na na 6 5.7 C, shotcrete None na None na na na na 8 6.8 D, shotcrete b 6.9 Air-filled void 17.25 by 14.75 75⁄8 12.4 by 12.1 7.6 12 11.3 E, shotcrete b 6.4 Water-filled void 15.75 by 14.5 7½ 15.5 by 13.3 7.6 12 11.0 F, shotcrete b 6.7 Air-filled void 17.125 by 14.75 3 18.1 by 15.6 3.5 12 11.2 G, shotcrete b 6.8 Water-filled void 15.5 by 14.25 3 16.0 by 14.7 4.2 12 10.7 (continued on next page)

148 H, shotcrete b 6.4 Thin cloth 12 by 12 8 14.0 by 10.7 7.2 12 10.2 I, shotcrete b 5.7 Thin cloth 12 by 12 4 11.0 by 14.0 3.9 12 10.4 J, shotcrete b 6.1 Thin cloth 12 by 12 3 13.1 by 12.0 2.9 12 10.4 K, shotcrete b 5.6 Thin cloth 12 by 12 2 12.3 by 13.4 3.1 12 10.2 L, shotcrete b 5.6 Thin cloth 12 by 12 1 14.0 by 13.3 Very shallow 12 10.3 M, shotcrete b 5.8 None na na na na 12 10.4 A2, concrete c NA None na na na na na na B2, concrete c NA 1 clay lump 6-∅ by 2 ~6 6.1 6.3 na na C2, concrete c NA 6 clay lumps 4-∅ by 2 ~3, 6, 9 3.1–4.1 2.7, 5.4, 8.5 na na D2, concrete c 6.0 at 8.0 on center None na na na na na na E2, concrete c 6.0 at 8.0 on center 1 clay lump 6-∅ by 2 ~6 4.2 4.6 na na F2, concrete c 6.0 at 8.0 on center 6 clay lumps 4-∅ by 2 ~3, 6, 9 2.9–3.9 2.4, 5.4, 7.8 na na Note: na = not applicable; NA = not available. a Two mats of No. 5 rebar, 4 in. from top and bottom, 8 in. on center. b One lattice girder in center of slab, sitting on bottom form, centroid of upper bar 5.25 in. from bottom, or ~6.25 in. from top. c One mat of No. 5 rebar, 6 in. from top, 8 in. on center. Table N.1. Detailed Defect Dimensions, Depth, and Cover and Spacing (in.) (continued) Specimen Name and Material Actual Reinforcement Cover and Spacing Measured Reinforcement Cover and Spacing Type of Defect Actual Dimensions of Defect Actual Depth of Defect Measured Dimensions of Defect Measured Depth of Defect Actual Specimen Depth Measured Specimen Depth

149 Eisenhower Memorial Tunnel, Dillon, CO Vshear = 2751 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Frequency: 50 kHz No significant defect noticed, except for strip of area (~9.4" wide, 16.2" deep) consistently found in other maps. Possibly structural steel reinforcement. Backsurface not discernible. Area tested as representative of sound concrete. Hoop reinf: ~4.2" deep @ ~9.9" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Dillon, CO Eisenhower Tunnel ET 10.4-1, 2 Segment 8 TAMU/TTI 10/2011 Figure N.1. Images of test site ET 10.4-1, 2.

150 Eisenhower Memorial Tunnel, Dillon, CO Vshear = 2751 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Frequency: 50 kHz No significant defect noticed, except for strip of area (~9.4" wide, 16.2" deep) consistently found in other maps. Possibly structural steel reinforcement. Backsurface not discernible. Area tested as representative of sound concrete. Hoop reinf: ~4.2" deep @ ~9.9" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Dillon, CO Eisenhower Tunnel ET 10.4-1, 2 Segment 8 TAMU/TTI 10/2011 Hoop reinforcement Volume-Scan C-Scan Longitudinal reinforcement Structural reinforcement B-Scan Figure N.2. UST images of test site ET 10.4-1, 2.

151 Frequency: 50 kHz No significant defect noticed, except for strip of area (~12.2" wide, 17.2" deep) consistently found in other maps. Possibly steel structural reinforcement. Backsurface not discernible. Area tested because of surface cracking and crazing, nearby stalactite formation. Could not test over stalactite crack due to obtrusions. Hoop reinf: ~3.7"-5.1" deep @ ~10.1" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Dillon, CO Eisenhower Tunnel ET 10.4-3 Segment 8 TAMU/TTI 10/2011 Eisenhower Memorial Tunnel, Dillon, CO Vshear = 2751 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 750 mm Figure N.3. Image of test site 10.4-3.

152 Frequency: 50 kHz No significant defect noticed, except for strip of area (~12.2" wide, 17.2" deep) consistently found in other maps. Possibly steel structural reinforcement. Backsurface not discernible. Area tested because of surface cracking and crazing, nearby stalactite formation. Could not test over stalactite crack due to obtrusions. Hoop reinf: ~3.7"-5.1" deep @ ~10.1" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Dillon, CO Eisenhower Tunnel ET 10.4-3 Segment 8 TAMU/TTI 10/2011 Eisenhower Memorial Tunnel, Dillon, CO Vshear = 2751 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 750 mm Hoop reinforcement Volume-Scan Longitudinal reinforcement Structural reinforcement B-Scan Strong echoes Strong echoes Surface defects Figure N.4. UST images of test site 10.4-3.

153 Frequency: 50 kHz No significant defect noticed, except for strip of area (~13.5" wide, 16.1" deep) consistently found in other maps. Possibly steel structural reinforcement. Backsurface not discernible. Area tested because of surface cracking and crazing and nearby joint. Hoop reinf: ~4.1" deep @ ~10.1" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Dillon, CO Eisenhower Tunnel ET 10.4-4, 5 Segment 10 TAMU/TTI 10/2011 Eisenhower Memorial Tunnel, Dillon, CO Vshear = 2751 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 750 mm Figure N.5. Image of test site ET 10.4-4, 5.

154 Frequency: 50 kHz No significant defect noticed, except for strip of area (~13.5" wide, 16.1" deep) consistently found in other maps. Possibly steel structural reinforcement. Backsurface not discernible. Area tested because of surface cracking and crazing and nearby joint. Hoop reinf: ~4.1" deep @ ~10.1" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Dillon, CO Eisenhower Tunnel ET 10.4-4, 5 Segment 10 TAMU/TTI 10/2011 Eisenhower Memorial Tunnel, Dillon, CO Vshear = 2751 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 750 mm Hoop reinforcement Volume-Scan Longitudinal reinforcement B-Scan Structural reinforcement Strong echoes C-Scan C-Scan Figure N.6. UST images of test site ET 10.4-4, 5.

155 Vshear = 2159 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 2500 mm Hanging Lake Tunnel, Glenwood Springs, CO Frequency: 50 kHz Apparent delamination extending 12.3" deep, originating from surface crack; possibly connecting to another crack located approximately 35" to the right of surface crack Backsurface possibly seen at 27.6" in depth. Severe cracking. Area also tested by BAM. Hoop reinf: 4.6"- 6.2" deep @ 15.7" on center. Longitudinal reinf: above and possibly below hoop reinforcement @ 14.1" on center. Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-1, 2, 3 Segment 57 + 3.4 TAMU/TTI 10/2011 Figure N.7. Image of test site HLT 10.5-1, 2, 3.

156 Vshear = 2159 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 2500 mm Hanging Lake Tunnel, Glenwood Springs, CO Frequency: 50 kHz Apparent delamination extending 12.3" deep, originating from surface crack; possibly connecting to another crack located approximately 35" to the right of surface crack Backsurface possibly seen at 27.6" in depth. Severe cracking. Area also tested by BAM. Hoop reinf: 4.6"- 6.2" deep @ 15.7" on center. Longitudinal reinf: above and possibly below hoop reinforcement @ 14.1" on center. Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-1, 2, 3 Segment 57 + 3.4 TAMU/TTI 10/2011 Backwall reflection or bottom layer of reinforcement Hoop reinforcement Delamination emanating from surface Delamination emanating from surface cracks Volume view showing (a) hoop and (b) longitudinal reinforcement, respectively, and (c) surface cracks. (a) (c) B-Scan B-Scan Volume-Scan (b) Figure N.8. UST images of test site HLT 10.5-1, 2, 3.

157 Frequency: 50 kHz Suspected debonding around east (right) side of joint. Surface crack around area might support this. Suspected debonding extends a maximum of 9" deep. Backsurface not detected. Area tested because of natural joint. This map should be extended east to detail more of possible debonding. Hoop reinf: ~3.6" deep on center. Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-4 Segments 54/55 Joint TAMU/TTI 10/2011 Vshear = 2159 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Hanging Lake Tunnel, Glenwood Springs, CO Figure N.9. Images of test site HLT 10.5-4.

158 Frequency: 50 kHz Suspected debonding around east (right) side of joint. Surface crack around area might support this. Suspected debonding extends a maximum of 9" deep. Backsurface not detected. Area tested because of natural joint. This map should be extended east to detail more of possible debonding. Hoop reinf: ~3.6" deep on center. Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-4 Segments 54/55 Joint TAMU/TTI 10/2011 Vshear = 2159 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Hanging Lake Tunnel, Glenwood Springs, CO Strong echoes Highly reflective region Strong echoes Hoop reinforcement B-Scan Volume-Scan Figure N.10. UST images of test site HLT 10.5-4.

159 Hanging Lake Tunnel, Glenwood Springs, CO Frequency: 50 kHz No significant defect noticeable. Backwall reflection varies 2-3" in depth. This may be lower reinforcement reflection or backwall delamination (see HLT 10.5-8,9). Backsurface possibly 29.6" - 32.4" deep. Area tested as a representation of sound cocnrete-no apparent cracks or defects. Hoop reinf: ~4.3"-5.1" deep @ 16.6" on center. Longitudinal reinf: above hoop reinforcement. Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-5, 6, 7 Segments 49 TAMU/TTI 10/2011 Vshear = 2159 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 2500 mm Figure N.11. Image of test site HLT 10.5-5, 6, 7.

160 Hanging Lake Tunnel, Glenwood Springs, CO Frequency: 50 kHz No significant defect noticeable. Backwall reflection varies 2-3" in depth. This may be lower reinforcement reflection or backwall delamination (see HLT 10.5-8,9). Backsurface possibly 29.6" - 32.4" deep. Area tested as a representation of sound cocnrete-no apparent cracks or defects. Hoop reinf: ~4.3"-5.1" deep @ 16.6" on center. Longitudinal reinf: above hoop reinforcement. Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-5, 6, 7 Segments 49 TAMU/TTI 10/2011 Vshear = 2159 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 2500 mm Backwall reflection Hoop reinforcement Hoop reinforcement Backwall Very shallow, highly reflective region B-Scan Volume-Scan Figure N.12. UST images of test site HLT 10.5-5, 6, 7.

161 Max Depth: 2500 mm Hanging Lake Tunnel, Glenwood Springs, CO Frequency: 50 kHz No significant defect noticeable. Backwall reflection varies 2-3" in depth. This may be lower reinforcement reflection or backwall delamination (see HLT 10.5-8,9). Backsurface possibly 24.5" - 29.6" deep. Area tested because of single surface crack. Note strong echoes emanating from region of reinforcement. This is possible sign of debonding. Hoop reinf: ~3.7" deep @ 15.9" on center. Longitudinal reinf: below hoop reinforcement. . Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-8, 9 Segments 49 TAMU/TTI 10/2011 Vshear = 2159 m/s X-step: 150 mm Y-step: 50 mm Figure N.13. Image of test site HLT 10.5-8, 9.

162 Max Depth: 2500 mm Hanging Lake Tunnel, Glenwood Springs, CO Frequency: 50 kHz No significant defect noticeable. Backwall reflection varies 2-3" in depth. This may be lower reinforcement reflection or backwall delamination (see HLT 10.5-8,9). Backsurface possibly 24.5" - 29.6" deep. Area tested because of single surface crack. Note strong echoes emanating from region of reinforcement. This is possible sign of debonding. Hoop reinf: ~3.7" deep @ 15.9" on center. Longitudinal reinf: below hoop reinforcement. . Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-8, 9 Segments 49 TAMU/TTI 10/2011 Vshear = 2159 m/s X-step: 150 mm Y-step: 50 mm Backwall reflection Hoop reinforcement Hoop reinforcement Backwall reflection B-Scan Volume-Scan Strong echoes from reinforcement region B-Scan Figure N.14. UST images of test site HLT 10.5-8, 9.

163 Y-step: 50 mm Max Depth: 1000 mm Hanging Lake Tunnel, Glenwood Springs, CO Frequency: 50 kHz Significant delamination/debonding discovered which stretched over 11', ranging from 8"- 20" below the surface. Backsurface not discernible due to high presence of delamination/debonding. Area tested because of severe surface cracking. Hoop reinf: ~2.9"-5.1" deep @ ~16.4" on center. Longitudinal reinf: above hoop reinforcement. Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-10, 11, 12 Segment 55 TAMU/TTI 10/2011 Vshear = 2159 m/s X-step: 150 mm Figure N.15. Images of test site HLT 10.5-10, 11, 12.

164 X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Hanging Lake Tunnel, Glenwood Springs, CO Frequency: 50 kHz Significant delamination/debonding discovered which stretched over 11', ranging from 8"- 20" below the surface. Backsurface not discernible due to high presence of delamination/debonding. The B-scan below shows variance in depth and the C- scans show the horizontal spread of the delamination/debonding. Hoop reinf: ~2.9"-5.1" deep @ ~16.4" on center. Longitudinal reinf: above hoop reinforcement. Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-10, 11, 12 Segment 55 TAMU/TTI 10/2011 Vshear = 2159 m/s Hoop reinforcement Curved delaminations/debonding Volume-Scan Curved delaminations/debonding B-Scan Curved delaminations/debonding C-Scans Longitudinal reinforcement Figure N.16. UST images of test site HLT 10.5-10, 11, 12.

165 Vshear = 2159 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Hanging Lake Tunnel, Glenwood Springs, CO Frequency: 50 kHz No significant defect noticed. Backsurface not discernible. Area tested on surface of tile. Hair-line crack present. Hoop reinf: ~5.1" deep @ ~16.3" on center. Longitudinal reinf: below and possible above hoop reinforcement @ ~14.0" on center. Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-13 Interior Tile Lining TAMU/TTI 10/2011 Figure N.17. Image of test site HLT 10.5-13.

166 Vshear = 2159 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Hanging Lake Tunnel, Glenwood Springs, CO Frequency: 50 kHz No significant defect noticed. Backsurface not discernible. Area tested on surface of tile. Hair-line crack present. Hoop reinf: ~5.1" deep @ ~16.3" on center. Longitudinal reinf: below and possible above hoop reinforcement @ ~14.0" on center. Defects Notes Reinf. Detail Glenwood Springs, CO Hanging Lake Tunnel HLT 10.5-13 Interior Tile Lining TAMU/TTI 10/2011 Hoop reinforcement Volume-Scan B-Scan C-Scan Longitudinal reinforcement Longitudinal reinforcement Figure N.18. UST images of test site HLT 10.5-13.

167 Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz No significant defect noticed. Backsurface at ~24.7" deep. Area tested as representative of sound concrete. Also tested because GPR data revealed different steel detail (c.f. with CBBT 10.11-3,4). Hoop reinf: ~2.4" deep @ ~4.4" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-1, 2 Sta. 471+80 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Figure N.19. Images of test site CBBT 10.11-1, 2.

168 Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz No significant defect noticed. Backsurface at ~24.7" deep. Area tested as representative of sound concrete. Also tested because GPR data revealed different steel detail (c.f. with CBBT 10.11-3,4). Hoop reinf: ~2.4" deep @ ~4.4" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-1, 2 Sta. 471+80 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Hoop reinforcement Volume-Scan B-Scan Backwall reflection C-Scan Figure N.20. UST images of test site CBBT 10.11-1, 2.

169 Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz No significant defect noticed. Backsurface at ~24.4" deep. Area tested as representative of sound concrete. Also tested because GPR data revealed different steel detail (c.f. with CBBT 10.11-1,2). Hoop reinf: ~2.3" deep @ ~11.8" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-3, 4 Sta. 473+56 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Figure N.21. Image of test site CBBT 10.11-3, 4.

170 Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz No significant defect noticed. Backsurface at ~24.4" deep. Area tested as representative of sound concrete. Also tested because GPR data revealed different steel detail (c.f. with CBBT 10.11-1,2). Hoop reinf: ~2.3" deep @ ~11.8" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-3, 4 Sta. 473+56 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Hoop reinforcement Volume-Scan B-Scan Backwall reflection C-Scan Longitudinal reinforcement Figure N.22. UST images of test site CBBT 10.11-3, 4.

171 Max Depth: 1000 mm Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Significant shallow defects, such as shallow cracks (~9" deep) and possibly shallow delaminations (~2" deep), which seem to produce the ringing. Backsurface at ~24.1" deep. Area tested because of live crack. Significant ringing may suggest debonding of longitudinal reinforcement. Hoop reinf: ~2.0"-2.6" deep @ ~12.0" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-5 Sta. 474+27 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 150 mm Y-step: 50 mm Figure N.23. Images of test site CBBT 10.11-5.

172 Max Depth: 1000 mm Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Significant shallow defects, such as shallow cracks (~9" deep) and possibly shallow delaminations (~2" deep), which seem to produce the ringing. Backsurface at ~24.1" deep. Area tested because of live crack. Significant ringing may suggest debonding of longitudinal reinforcement. Hoop reinf: ~2.0"-2.6" deep @ ~12.0" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-5 Sta. 474+27 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 150 mm Y-step: 50 mm Hoop reinforcement Volume-Scan B-Scan Backwall reflection C-Scan Longitudinal reinforcement B-Scan Ringing from shallow defects Shallow defects Ringing from shallow defects Figure N.24. UST images of test site CBBT 10.11-5.

173 Y-step: 50 mm Max Depth: 1000 mm Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Hammer tapping revealed hollow region as shown by shallow reflective region in the C- and B-scans. Significant cupped-shaped delaminations as deep as 19.2" Backsurface at 24.1"-26.0" deep. Area tested because of high dielectric reading from GPR scan. No significant visual distress noticeable, but hammer sounding revealed shallow delamination in Region II. Hoop reinf: ~2.2" deep @ ~12.1" on center. Longitudinal reinf: below hoop reinforcement @ 16.2" on center. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-7, 8 (Region II) Sta. 486+67 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 150 mm Figure N.25. Images of test site CBBT 10.11-7, 8.

174 Y-step: 50 mm Max Depth: 1000 mm Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Hammer tapping revealed hollow region as shown by shallow reflective region in the C- and B-scans. Significant cupped-shaped delaminations as deep as 19.2" Backsurface at 24.1"-26.0" deep. Area tested because of high dielectric reading from GPR scan. No significant visual distress noticeable, but hammer sounding revealed shallow delamination in Region II. Hoop reinf: ~2.2" deep @ ~12.1" on center. Longitudinal reinf: below hoop reinforcement @ 16.2" on center. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-7, 8 (Region II) Sta. 486+67 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 150 mm Hoop reinforcement Volume-Scan B-Scan Longitudinal reinforcement C-Scan Shallow delamination Volume-Scan (Isosurface rendering) Backwall reflection Deep delamination Figure N.26. UST images of test site CBBT 10.11-7, 8.

175 X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Significant cracks up to 8.6" deep. Backsurface at 24.3"-26.0" deep. Area tested because of high dielectric reading from GPR scan. No significant visual distress noticeable. Hoop reinf: ~2.0"-3.0" deep @ ~12.2" on center. Longitudinal reinf: below hoop reinforcement @ 19.8" on center. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-9 (Region I) Sta. 486+67 TAMU/TTI 10/2011 Vshear = 2710 m/s Figure N.27. Images of test site CBBT 10.11-9.

176 X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Significant cracks up to 8.6" deep. Backsurface at 24.3"-26.0" deep. Area tested because of high dielectric reading from GPR scan. No significant visual distress noticeable. Hoop reinf: ~2.0"-3.0" deep @ ~12.2" on center. Longitudinal reinf: below hoop reinforcement @ 19.8" on center. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-9 (Region I) Sta. 486+67 TAMU/TTI 10/2011 Vshear = 2710 m/s Hoop reinforcement Volume-Scan (Isosurface rendering) C-Scan Backwall reflection Ringing from shallow defects Shallow defects Longitudinal reinforcement Volume-Scan B-Scan Shallow defects Figure N.28. UST images of test site CBBT 10.11-9.

177 Vshear = 2710 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Heavy ringing made internal inspection difficult. Possible deep delamination (~17.7" deep and possibly 19" wide) and evidence of surface crack extending ~9.8" deep. Backsurface at 22.7"-25.9" deep. Area tested because of large surface crack and small area of water intrusion. Hoop reinf: ~2.7"-3.2" deep @ ~11.7"-12.4" on center. Second layer of hoop reinf. directly beneath top layer. Longitudinal reinf: below first layer of hoop reinforcement @ ~17.1" on center. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-10 Sta. 491+25 TAMU/TTI 10/2011 Figure N.29. Images of test site CBBT 10.11-10.

178 Vshear = 2710 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 1000 mm Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Heavy ringing made internal inspection difficult. Possible deep delamination (~17.7" deep and possibly 19" wide) and evidence of surface crack extending ~9.8" deep. Backsurface at 22.7"-25.9" deep. Area tested because of large surface crack and small area of water intrusion. Hoop reinf: ~2.7"-3.2" deep @ ~11.7"-12.4" on center. Second layer of hoop reinf. directly beneath top layer. Longitudinal reinf: below first layer of hoop reinforcement @ ~17.1" on center. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.11-10 Sta. 491+25 TAMU/TTI 10/2011 Hoop reinforcement C-Scan B-Scan Longitudinal reinforcement B-Scan Shallow crack Volume-Scan Strong ringing Backwall reflection Deep delamination B-Scan B-Scan Backwall reflection Figure N.30. UST images of test site CBBT 10.11-10.

179 Frequency: 50 kHz Heavy ringing made internal inspection difficult. Possible deep delamination (~15.7" deep and 20.3" wide). Backsurface at 25.0"-30.0" deep. Area tested was tiled lining over a joint where tile has debonded. Determined area via hammer sounding. Hoop reinf: ~4.3"-7.7" deep @ ~12.1" on center. Second layer of hoop reinf. seen beneath top layer in one location-possibly splice area. Longitudinal reinf: below hoop reinforcement @ ~13.0" on center. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT TILE 10.11-11 Approx. Sta. 488 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 110 mm Y-step: 110 mm Max Depth: 750 mm Chesapeake Channel Tunnel, Norfolk, VA Figure N.31. Image of test site CBBT TILE 10.11-11.

180 Frequency: 50 kHz Heavy ringing made internal inspection difficult. Possible deep delamination (~15.7" deep and 20.3" wide). Backsurface at 25.0"-30.0" deep. Area tested was tiled lining over a joint where tile has debonded. Determined area via hammer sounding. Hoop reinf: ~4.3"-7.7" deep @ ~12.1" on center. Second layer of hoop reinf. seen beneath top layer in one location-possibly splice area. Longitudinal reinf: below hoop reinforcement @ ~13.0" on center. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT TILE 10.11-11 Approx. Sta. 488 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 110 mm Y-step: 110 mm Max Depth: 750 mm Chesapeake Channel Tunnel, Norfolk, VA Hoop reinforcement B-Scan Backwall reflection Longitudinal reinforcement or duct B-Scan Deep delaminations Volume-Scan Backwall reflection C-Scan B-Scan Hoop reinforcement Longitudinal reinforcement or duct Figure N.32. UST images of test site CBBT TILE 10.11-11.

181 Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Heavy ringing made internal inspection difficult. Possibly multiple cracks as deep as 8.6". Backsurface at 28.1"-31.0" deep. Area tested was tiled lining. Hammer sounding did not indicate debonding, but SPACETEC infrared scans showed area of question.. Hoop reinf: ~4.8"-9.4" deep @ ~11.7" on center. Longitudinal reinf: below and possibly above hoop reinforcement. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT TILE 10.11-12 Sta. 486-09 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 110 mm Y-step: 110 mm Max Depth: 1000 mm Figure N.33. Image of test site CBBT TILE 10.11-12.

182 Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Heavy ringing made internal inspection difficult. Possibly multiple cracks as deep as 8.6". Backsurface at 28.1"-31.0" deep. Area tested was tiled lining. Hammer sounding did not indicate debonding, but SPACETEC infrared scans showed area of question.. Hoop reinf: ~4.8"-9.4" deep @ ~11.7" on center. Longitudinal reinf: below and possibly above hoop reinforcement. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT TILE 10.11-12 Sta. 486-09 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 110 mm Y-step: 110 mm Max Depth: 1000 mm Hoop reinforcement Backwall reflection Longitudinal reinforcement Surface cracks, delaminations Volume-Scan Backwall reflection C-Scan B-Scans Hoop reinforcement B-Scan D-Scan Figure N.34. UST images of test site CBBT TILE 10.11-12.

183 Max Depth: 1000 mm Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Apparent delamination 20.2" deep and 27.4" wide. Backsurface at 26.6"- 28.4" deep. Area tested because of surface crack and varying backwall reflections from single- point evaluations. Hoop reinf: ~2.0"-3.6" deep @ 12.1" on center. Longitudinal reinf: below hoop reinforcment. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.13 Sta. 481+76 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 150 mm Y-step: 50 mm Figure N.35. Image of test site CBBT 10.11-13.

184 Max Depth: 1000 mm Chesapeake Channel Tunnel, Norfolk, VA Frequency: 50 kHz Apparent delamination 20.2" deep and 27.4" wide. Backsurface at 26.6"- 28.4" deep. Area tested because of surface crack and varying backwall reflections from single- point evaluations. Hoop reinf: ~2.0"-3.6" deep @ 12.1" on center. Longitudinal reinf: below hoop reinforcment. Defects Notes Reinf. Detail Norfolk, VA Chesapeake Tunnel CBBT 10.13 Sta. 481+76 TAMU/TTI 10/2011 Vshear = 2710 m/s X-step: 150 mm Y-step: 50 mm Hoop reinforcement Deep delamination Longitudinal reinforcement C-Scan Backwall reflection C-Scan B-Scan Volume-Scan Figure N.36. UST images of test site CBBT 10.11-13.

185 Y-step: 110 mm Max Depth: 500 mm Washburn Tunnel, Houston, TX Frequency: 50 kHz Significant shallow debonding/delamination. Deep delamination approximately 13" deep (B-scan image). Backsurface not discernible. Area tested because of debonding located via hammer sounding. Hoop reinf: ~6.8" deep. Defects Notes Reinf. Detail Houston, TX Washburn Tunnel WT 9.16-1 West Side TAMU/TTI 9/2011 Vshear = 2710 m/s X-step: 110 mm Figure N.37. Images of test site WT 9.16-1.

186 Y-step: 110 mm Max Depth: 500 mm Washburn Tunnel, Houston, TX Frequency: 50 kHz Significant shallow debonding/delamination. Deep delamination approximately 13" deep (B-scan image). Backsurface not discernible. Area tested because of debonding located via hammer sounding. Hoop reinf: ~6.8" deep. Defects Notes Reinf. Detail Houston, TX Washburn Tunnel WT 9.16-1 West Side TAMU/TTI 9/2011 Vshear = 2710 m/s X-step: 110 mm Hoop reinforcement Volume-Scan B-Scan Deep delamination Shallow debonding C-Scan Shallow debonding Figure N.38. UST images of test site WT 9.16-1.

187 X-step: 110 mm Y-step: 110 mm Max Depth: 500 mm Washburn Tunnel, Houston, TX Frequency: 50 kHz Significant shallow and deep debonding/delamination. Delamination as deep as approximately 18" deep (B-scan image). Backsurface not discernible. Area tested because of debonding located via hammer sounding. Hoop reinf: ~4.8"-5.2" deep @ 12.2 on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Houston, TX Washburn Tunnel WT 9.16-2 West Side TAMU/TTI 9/2011 Vshear = 2710 m/s Figure N.39. Image of test site WT 9.16-2.

188 X-step: 110 mm Y-step: 110 mm Max Depth: 500 mm Washburn Tunnel, Houston, TX Frequency: 50 kHz Significant shallow and deep debonding/delamination. Delamination as deep as approximately 18" deep (B-scan image). Backsurface not discernible. Area tested because of debonding located via hammer sounding. Hoop reinf: ~4.8"-5.2" deep @ 12.2 on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Houston, TX Washburn Tunnel WT 9.16-2 West Side TAMU/TTI 9/2011 Vshear = 2710 m/s Hoop reinforcement Volume-Scan B-Scans Shallow debonding C-Scans Region below tile debonding Delamination at reinforcement Figure N.40. UST images of test site WT 9.16-2.

189 Vshear = 2710 m/s X-step: 110 mm Y-step: 110 mm Max Depth: 500 mm Washburn Tunnel, Houston, TX Frequency: 50 kHz Significant delaminations/debonding throughout. Delaminations as deep as 10.7" below surface. Backsurface not discernible. Area tested because of debonding located via hammer sounding. Hoop reinf: ~4.9" deep @ 13.4" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Houston, TX Washburn Tunnel WT 9.16-3 West Side TAMU/TTI 9/2011 Figure N.41. Image of test site WT 9.16-3.

190 Vshear = 2710 m/s X-step: 110 mm Y-step: 110 mm Max Depth: 500 mm Washburn Tunnel, Houston, TX Frequency: 50 kHz Significant delaminations/debonding throughout. Delaminations as deep as 10.7" below surface. Backsurface not discernible. Area tested because of debonding located via hammer sounding. Hoop reinf: ~4.9" deep @ 13.4" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Houston, TX Washburn Tunnel WT 9.16-3 West Side TAMU/TTI 9/2011 B-Scans Delaminations Volume-Scan Hoop reinforcement C-Scans Shallow debonding Figure N.42. UST images of test site WT 9.16-3.

191 Frequency: 50 kHz Significant delaminations/debonding throughout. Possible delaminations 11.7" deep. Backsurface not discernible. Area tested because of debonding located via hammer sounding. Hoop reinf: ~4.7" deep @ 11.7" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Houston, TX Washburn Tunnel WT 9.16-4 West Side TAMU/TTI 9/2011 Vshear = 2710 m/s X-step: 110 mm Y-step: 110 mm Max Depth: 500 mm Washburn Tunnel, Houston, TX Figure N.43. Image of test site WT 9.16-4.

192 Frequency: 50 kHz Significant delaminations/debonding throughout. Possible delaminations 11.7" deep. Backsurface not discernible. Area tested because of debonding located via hammer sounding. Hoop reinf: ~4.7" deep @ 11.7" on center. Longitudinal reinf: below hoop reinforcement. Defects Notes Reinf. Detail Houston, TX Washburn Tunnel WT 9.16-4 West Side TAMU/TTI 9/2011 Vshear = 2710 m/s X-step: 110 mm Y-step: 110 mm Max Depth: 500 mm Washburn Tunnel, Houston, TX Delamination Volume-Scan B-Scans Shallow debonding C-Scans Shallow delaminations, cracks Hoop Reinforcement Figure N.44. UST images of test site WT 9.16-4.

193 Max Depth: 500 mm Interstate 20, Ft. Worth, TX Frequency: 50 kHz Significant delamination on both sides of surface crack, ranging from 4.2"-5.0" from top surface. Top layer of pavement 10.2" below surface. Area tested because of transverse surface cracking. Pavement depth confirmed by 2 cores, both indicating 10.2" thickness and one indicating 5.0" reinf. Longitudinal reinf.: ~4.6"- 5.0" deep @ 5.6" on center. No transverse reinforcement located in this area. Defects Notes Reinf. Detail Ft. Worth, TX I-20 IH20 9.27-1 MP 426 + 0.5, RM 2871 TAMU/TTI 9/2011 Vshear = 2770 m/s X-step: 150 mm Y-step: 50 mm Figure N.45. Images of test site WT 9.27-1.

194 Max Depth: 500 mm Interstate 20, Ft. Worth, TX Frequency: 50 kHz Significant delamination on both sides of surface crack, ranging from 4.2"-5.0" from top surface. Top layer of pavement 10.2" below surface. Area tested because of transverse surface cracking. Pavement depth confirmed by 2 cores, both indicating 10.2" thickness and one indicating 5.0" reinf. Longitudinal reinf.: ~4.6"- 5.0" deep @ 5.6" on center. No transverse reinforcement located in this area. Defects Notes Reinf. Detail Ft. Worth, TX I-20 IH20 9.27-1 MP 426 + 0.5, RM 2871 TAMU/TTI 9/2011 Vshear = 2770 m/s X-step: 150 mm Y-step: 50 mm Volume-Scan Longitudinal reinforcement B-Scans Top layer interface Delamination C-Scan Delamination Figure N.46. UST images of test site IH20 9.27-1.

195 Y-step: 50 mm Max Depth: 500 mm Interstate 20, Ft. Worth, TX Frequency: 50 kHz Significant delamination on both sides of surface crack, ranging from 4.5"-5.3" from top surface. Top layer of pavement 10.4" below surface. Area tested because of transverse surface cracking. Pavement depth confirmed by 2 cores, indicating 9.4"- 10.4" thickness. Longitudinal reinf.: ~4.5"- 5.2" deep @ 7.1" on center. No transverse reinforcement located in this area. Defects Notes Reinf. Detail Ft. Worth, TX I-20 IH20 9.27-2 MP 426 + 0.5, RM 2871 TAMU/TTI 9/2011 Vshear = 2770 m/s X-step: 150 mm Figure N.47. Images of test site IH20 9.27-2.

196 Y-step: 50 mm Max Depth: 500 mm Interstate 20, Ft. Worth, TX Frequency: 50 kHz Significant delamination on both sides of surface crack, ranging from 4.5"-5.3" from top surface. Top layer of pavement 10.4" below surface. Area tested because of transverse surface cracking. Pavement depth confirmed by 2 cores, indicating 9.4"- 10.4" thickness. Longitudinal reinf.: ~4.5"- 5.2" deep @ 7.1" on center. No transverse reinforcement located in this area. Defects Notes Reinf. Detail Ft. Worth, TX I-20 IH20 9.27-2 MP 426 + 0.5, RM 2871 TAMU/TTI 9/2011 Vshear = 2770 m/s X-step: 150 mm Volume-Scan Longitudinal reinforcement B-Scan Top layer interface B-scan C-Scan Delamination Top layer interface Figure N.48. UST images of test site IH20 9.27-2.

197 X-step: 150 mm Y-step: 50 mm Max Depth: 500 mm Interstate 20, Ft. Worth, TX Frequency: 50 kHz Significant delamination on both sides of surface crack, ranging from 4.6"-5.1" from top surface. Top layer of pavement approximately 10.2" below surface. Area tested because of transverse surface cracking. Pavement depth confirmed by 2 cores, indicating 10.2" thickness. Longitudinal reinf.: ~4.8"- 5.0" deep @ 7.2" on center. No transverse reinforcement located in this area. Defects Notes Reinf. Detail Ft. Worth, TX I-20 IH20 9.27-3 MP 426 + 0.5, RM 2871 TAMU/TTI 9/2011 Vshear = 2770 m/s Figure N.49. Images of test site IH20 9.27-3.

198 X-step: 150 mm Y-step: 50 mm Max Depth: 500 mm Interstate 20, Ft. Worth, TX Frequency: 50 kHz Significant delamination on both sides of surface crack, ranging from 4.6"-5.1" from top surface. Top layer of pavement approximately 10.2" below surface. Area tested because of transverse surface cracking. Pavement depth confirmed by 2 cores, indicating 10.2" thickness. Longitudinal reinf.: ~4.8"- 5.0" deep @ 7.2" on center. No transverse reinforcement located in this area. Defects Notes Reinf. Detail Ft. Worth, TX I-20 IH20 9.27-3 MP 426 + 0.5, RM 2871 TAMU/TTI 9/2011 Vshear = 2770 m/s Volume-Scan Longitudinal reinforcement B-Scan Top layer interface Delamination C-Scan Delamination B-scan Figure N.50. UST images of test site IH20 9.27-3.

199 Vshear = 2770 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 500 mm Interstate 20, Ft. Worth, TX Frequency: 50 kHz Significant delamination on both sides of surface crack, approximately 5.0" from top surface. Top layer of pavement approximately 10.1" below surface. Area tested because of transverse surface cracking. No cores taken in this location. Longitudinal reinf.: ~4.6"- 5.2" deep @ 7.0" on center. No transverse reinforcement located in this area. Defects Notes Reinf. Detail Ft. Worth, TX I-20 IH20 9.27-5 MP 426 + 0.5, RM 2871 TAMU/TTI 9/2011 Figure N.51. Image of test site IH20 9.27-5.

200 Vshear = 2770 m/s X-step: 150 mm Y-step: 50 mm Max Depth: 500 mm Interstate 20, Ft. Worth, TX Frequency: 50 kHz Significant delamination on both sides of surface crack, approximately 5.0" from top surface. Top layer of pavement approximately 10.1" below surface. Area tested because of transverse surface cracking. No cores taken in this location. Longitudinal reinf.: ~4.6"- 5.2" deep @ 7.0" on center. No transverse reinforcement located in this area. Defects Notes Reinf. Detail Ft. Worth, TX I-20 IH20 9.27-5 MP 426 + 0.5, RM 2871 TAMU/TTI 9/2011 Volume-Scan Longitudinal reinforcement B-Scans Top layer interface Delamination C-Scan Top layer interface Figure N.52. UST images of test site IH20 9.27-5.

201 Max Depth: 1000 mm George Bush International Airport, Houston, TX Frequency: 50 kHz Significant debonding at at runway/subbase (7.6"-8.1" deep) and verified by coring. Possible further debonding in deeper layers (26.9" and 37.7" deep). Top layer of pavement approximately 7.6"-8.1" below surface; second layer 26.9" below surface; third layer 37.7" below surface.Area tested because of surface cracking and hammer sounding revealing possible debonding. Image is of typical runway segment. None. Defects Notes Reinf. Detail Houston, TX IAH IAH 6.9-1 Sta 83+00 T/W WA E TAMU/TTI 6/2011 Vshear = 2885 m/s X-step: 200 mm Y-step: 100 mm Figure N.53. Image of test site IAH 6.9-1.

202 Max Depth: 1000 mm George Bush International Airport, Houston, TX Frequency: 50 kHz Significant debonding at at runway/subbase (7.6"-8.1" deep) and verified by coring. Possible further debonding in deeper layers (26.9" and 37.7" deep). Top layer of pavement approximately 7.6"-8.1" below surface; second layer 26.9" below surface; third layer 37.7" below surface.Area tested because of surface cracking and hammer sounding revealing possible debonding. Image is of typical runway segment. None. Defects Notes Reinf. Detail Houston, TX IAH IAH 6.9-1 Sta 83+00 T/W WA E TAMU/TTI 6/2011 Vshear = 2885 m/s X-step: 200 mm Y-step: 100 mm Volume-Scan C-Scan Delaminated area, first layer interface Sound area B-Scans First layer interface Third layer interface Second layer interface Figure N.54. UST images of test site IAH 6.9-1.

203 Y-step: 100 mm Max Depth: 1000 mm George Bush International Airport, Houston, TX Frequency: 50 kHz Significant debonding at at runway/subbase (7.1" deep) and verified by coring. Possible further debonding in deeper layers (25.6" and 37.5" deep). Top layer of pavement approximately 7.1" below surface; second layer 25.6" below surface; third layer 37.5" below surface. Area tested because of surface cracking and hammer sounding revealing possible delaminations. Image is of typical runway segment. None. Defects Notes Reinf. Detail Houston, TX IAH IAH 6.9-2 Sta 82+75 T/W WA E TAMU/TTI 6/2011 Vshear = 2885 m/s X-step: 200 mm Figure N.55. Image of test site IAH 6.9-2.

204 Y-step: 100 mm Max Depth: 1000 mm George Bush International Airport, Houston, TX Frequency: 50 kHz Significant debonding at at runway/subbase (7.1" deep) and verified by coring. Possible further debonding in deeper layers (25.6" and 37.5" deep). Top layer of pavement approximately 7.1" below surface; second layer 25.6" below surface; third layer 37.5" below surface. Area tested because of surface cracking and hammer sounding revealing possible delaminations. Image is of typical runway segment. None. Defects Notes Reinf. Detail Houston, TX IAH IAH 6.9-2 Sta 82+75 T/W WA E TAMU/TTI 6/2011 Vshear = 2885 m/s X-step: 200 mm Volume-Scan C-Scans Delaminated area, second layer interface Sound area B-Scans First layer interface Third layer interface Second layer interface Delaminated area, first layer interface Figure N.56. UST images of test site IAH 6.9-2.