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Federal Highway Administration > Publications > Research > Structures > Long-Term Performance of Epoxy-Coated Reinforcing Steel in Heavy Salt-Contaminated Concrete

Publication Number: FHWA-HRT-04-090
Date: JUNE 2004

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Appendix A. PHOTOGRAPHS OF TEST SLABS AT END OF OUTDOOR EXPOSURE AND AUTOPSIED BARS

 

Figure 45. Slab #1 front, rear, and top views with specifications
Figure 45. Slab #1 front, rear, and top views with specifications. Photos. (A) Slab number 1 front view shows the 1B label on the left and 1A on the right. The top has two green spots indicating bars and the bottom has four with no corrosion or staining. Wires connect to the top left and all four bottom bars.
a) Front View
Figure 45. Slab #1 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled and has only one wire in the top left bar with clean concrete and no corrosion.
b) Rear View
Figure 45. Slab #1 front, rear, and top views with specifications. Photos. (C) The top view is smooth and uncracked.
c) Top View
d) Slab specifications
Specimen ID 1A 1B
Top mat Coating D Coating D
Bar shape (straight/bent) Bent Bent
Coating defect (%) 0.5 0.004
Bottom mat Black
Coating defect (%) N/A N/A
Precracked No No

Figure 46. Slab #1 extracted rebars condition. Photo. Before autopsy, the top mat bent ECRs are yellow-colored with several coating defects circled in red and black.
a) Top bars

Figure 46. Slab #1 extracted rebars condition. Photo. Before autopsy, the bottom mat straight black bars show corrosion on the right ends and white concrete residue adhered to the bar throughout.
b) Bottom bars

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars

Figure 46. Slab #1 extracted rebars condition


Figure 47. Slab #1 after autopsy. Photo. After autopsy, the top mat bent ECRs are yellow-colored with the left (B-T) severally delaminated with corroded substrate showing.
a) Top bars

Figure 47. Slab #1 after autopsy. Photo. After autopsy, the cleaned bottom mat straight black bars show corrosion on the ends but otherwise are uniformly gray.
b) Bottom bars

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars

Figure 47. Slab #1 after autopsy


Figure 48. Slab #2 front, rear, and top views with specifications
Figure 48. Slab #2 front, rear, and top views with specifications. Photos. (A) Slab number 2 front view shows the 2B label on the left and 2A on the right. The top has two green spots indicating bars and the bottom left bar has a corrosion spot while the concrete and the rest are clean. Wires connect the top and bottom bars of 2B and the same for 2A.
a) Front View
Figure 48. Slab #2 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled and clean with no wires.
b) Rear View
Figure 48. Slab #2 front, rear, and top views with specifications. Photos. (C) The top view is smooth and uncracked.
c) Top View
d) Slab Specifications
Specimen ID 2A 2B
Top mat Coating F Coating F
Bar shape (straight/bent) Straight Straight
Coating defect (%) 0.004 0.5
Bottom mat Coating F
Coating defect (%) 0.004 0.5
Precracked No No

Figure 49. Slab #2 extracted rebars condition. Photo. Before autopsy, the top mat straight ECRs are shiny olive green. The second from the top ECR (B-T) shows deteriorated coating condition.

Figure 49. Slab #2 extracted rebars condition

Figure 50. Slab #2 after autopsy. Photo. After autopsy, a top mat ECR labeled B-T shows significant delamination and corrosion on the substrate. The right half of the fifth bar down (B-B1) shows a similar corrosion pattern. The remaining bars show good condition.

Figure 50. Slab #2 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars


Figure 51. Slab #3 front, rear, and top views with specifications
Figure 51. Slab #3 front, rear, and top views with specifications. Photos. (A) Slab number 3 front view shows the 3B label on the left and 3A on the right. The top right bar and bottom 3B right and all 3As show corrosion. Wires connect the top and bottom bars of 3B and the same for 3A.
a) Front View
Figure 51. Slab #3 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled and shows no wires. Heavy corrosion shows around the top left bar that has seeped into the center.
b) Rear view
Figure 51. Slab #3 front, rear, and top views with specifications. Photos. (C) The top view is mottled gray and has a crack on the right side.
c) Top View
d) Slab specifications
Specimen ID 3A 3B
Top mat Coating C Coating C
Bar shape (straight/bent) Straight Straight
Coating defect (%) 0.5 0.004
Bottom mat Black
Coating defect (%) N/A N/A
Precracked No No

Figure 52. Slab #3 extracted rebars condition. Photo. Before autopsy, the top mat straight ECR (A-T) looks mossy green with hairline cracks and coating blisters. The second ECR is spring green with hairline cracks in the center. The bottom mat four black bars show white concrete residue encrusted with rust.

Figure 52. Slab #3 extracted rebars condition

Figure 53. Slab #3 after autopsy. Photo. After autopsy, a top mat ECR (A-T) is completely delaminated with corrosion spots, the second top mat ECR (B-T) is lime green with significant delamination and corrosion in the center, and the cleaned bottom mat four black bars look good with minimal corrosion damage.

Figure 53. Slab #3 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars


Figure 54. Slab #4 front, rear, and top views with specifications
Figure 54. Slab #4 front, rear, and top views with specifications. Photos. (A) Slab number 4 front view shows the 4B label on the left and 4A on the right. The top two bars and the bottom and the third from the left on the bottom show corrosion. Wires connect the top and bottom bars of 4B and the same for 4A.
a) Front View
Figure 54. Slab #4 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled and shows one wire. The corrosion pattern is the same as the front, but heavier.
b) Rear View
Figure 54. Slab #4 front, rear, and top views with specifications. Photos. (C) The top view is mottled gray and has several cracks, mainly radiating from the right side.
c) Top View
d) Slab specifications
Specimen ID 4A 4B
Top mat Coating C Coating C
Bar shape (straight/bent) Bent Bent
Coating defect (%) 0.5 0.004
Bottom mat Black
Coating defect (%) N/A N/A
Precracked No No

Figure 55. Slab #4 extracted rebars condition. Photo. Before autopsy, the top mat bent ECRs exhibit severe coating damage.
a) Top bars

Figure 55. Slab #4 extracted rebars condition. Photo. Before autopsy, the bottom mat straight black bars show minor dark discoloration and concrete residue adhered on the surface.
b) Bottom bars

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars

Figure 55. Slab #4 extracted rebars condition


Figure 56. Slab #4 after autopsy. Photo. After autopsy, the top mat bent ECRs are completely delaminated and corroded.
a) Top bars

Figure 56. Slab #4 after autopsy. Photo. After autopsy, the cleaned bottom mat bars are dark-colored and show good performance with minimal corrosion damage.
b) Bottom bars

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars

Figure 56. Slab #4 after autopsy


Figure 57. Slab #5 front, rear, and top views with specifications
Figure 57. Slab #5 front, rear, and top views with specifications. Photos. (A) Slab number 5 front view shows the 5B label on the left and 5A on the right. The top bars show corrosion and the first and second from the left on the bottom have corrosion with cracks throughout. Wires connect the top and bottom bars of 5B and the same for 5A.
a) Front View
Figure 57. Slab #5 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled with cracks and corrosion on the top bars and cracks in the third from the left bar.
b) Rear View
Figure 57. Slab #5 front, rear, and top views with specifications. Photos. (C) The top view is mottled gray and has several vertical cracks with a large corrosion spot in the middle.
c) Top View
d) Slab specifications
Specimen ID 5A 5B
Top mat Black Black
Bar shape (straight/bent) Straight Straight
Coating defect (%) N/A N/A
Bottom mat Black
Coating defect (%) N/A N/A
Precracked No No

Figure 58. Slab #5 extracted rebars condition. Photo. Before autopsy, the two top mat straight black bars (A-T and B-T,) exhibit severe corrosion. The bottom mat four black bars (A-B1, A-B2, B-B1 and B-B2) show minor corrosion with some concrete residue.

Figure 58. Slab #5 extracted rebars condition

Figure 59. Slab #5 after autopsy. Photo. After autopsy, two top mat black bars (A-T and B-T) reveal significant metal loss due to intensive corrosion The cleaned two bottom mat black bars (A-B1 and B-B2) show moderate pitting corrosion. The remaining two bottom black bars (A-B2 and B-B1) show shiny surfaces with generally good condition except for rust on the right end of B-B1.

Figure 59. Slab #5 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars


Figure 60. Slab #6 front, rear, and top views with specifications
Figure 60. Slab #6 front, rear, and top views with specifications. Photos. (A) Slab number 6 front view shows the 6B label on the left and 6A on the right. The top right bar shows corrosion seeping to between the third and four bars on the bottom with minor cracks. Wires connect the top and bottom bars of 6B and the same for 6A.
a) Front View
Figure 60. Slab #6 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled with minor cracks and the same corrosion pattern radiating into the cracks as the front view.
b) Rear View
Figure 60. Slab #6 front, rear, and top views with specifications. Photos. (C) The top view is mottled gray and has one prominent vertical crack.
c) Top View
d) Slab specifications
Specimen ID 6A 6B
Top mat Coating B Coating B
Bar shape (straight/bent) Straight Straight
Coating defect (%) 0.5 0.004
Bottom mat Black
Coating defect (%) N/A N/A
Precracked No No

Figure 61. Slab #6 extracted rebars condition. Photo. Before autopsy, one of the top mat straight ECRs (B-T, mistakenly labeled for A-T) exhibits significant coating degradation due to corrosion. The other top mat ECR (A-T, mistakenly labeled for B-T) shows good condition. The bottom mat four black bars show no corrosion.

Figure 61. Slab #6 extracted rebars condition

Figure 62. Slab #6 after autopsy. Photo. After autopsy, a top mat ECR (A-T) is completely delaminated with significant substrate corrosion and the other top mat ECR (B-T) still looks very good without noticeable coating damage. The cleaned bottom mat four black bars look good.

Figure 62. Slab #6 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars


Figure 63. Slab #7 front, rear, and top views with specifications
Figure 63. Slab #7 front, rear, and top views with specifications. Photos. (A) Slab number 7 front view shows the 7B label on the left and 7A on the right. The top and bottom right bars show corrosion. Wires connect the top and bottom bars of 7B and the same for 7A.
a) Front View
Figure 63. Slab #7 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled with a water dike and corrosion around all the bars except the top right.
b) Rear View
Figure 63. Slab #7 front, rear, and top views with specifications. Photos. (C) The top view is mottled gray and shows the two prominent vertical precracks.
c) Top View
d) Slab specifications
Specimen ID 7A 7B
Top mat Coating A Coating A
Bar shape (straight/bent) Straight Straight
Coating defect (%) 0.5 0.004
Bottom mat Black
Coating defect (%) N/A N/A
Precracked Yes Yes

Figure 64. Slab #7 extracted rebars condition. Photo. Before autopsy, the two top mat straight ECRs (A-T and B-T) exhibit hairline cracks and coating blisters with coating discoloration on the A-T. The bottom mat four black bars exhibit moderate corrosion .

Figure 64. Slab #7 extracted rebars condition

Figure 65. Slab #7 after autopsy. Photo. After autopsy, a top mat straight ECR (A-T) is completely delaminated due to extensive corrosion, and the second ECR(B-T) shows moderate coating delamination. The cleaned bottom mat four black bars look good without sign of corrosion.

Figure 65. Slab #7 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars


Figure 66. Slab #8 front, rear, and top views with specifications
Figure 66. Slab #8 front, rear, and top views with specifications. Photos. (A) Slab number 8 front view shows the faint 8B label on the left and 8A on the right. Cracks show between the bars and with corrosion around them with the top left and third on the bottom the worst. Wires connect the top and bottom bars of 8A and on the bottom of 8B.
a) Front View
Figure 66. Slab #8 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled with the water dike broken off. Cracks appear around all the bars, and the worst corrosion is around the top bars.
b) Rear View
Figure 66. Slab #8 front, rear, and top views with specifications. Photos. (C) The top view is mottled gray and has prominent corrosion marks in the lower right corner.
c) Top View
d) Slab specifications
Specimen ID 8A 8B
Top mat Coating F Coating F
Bar shape (straight/bent) Bent Bent
Coating defect (%) 0.004 0.5
Bottom mat Black
Coating defect (%) N/A N/A
Precracked No No

Figure 67. Slab #8 extracted rebars condition. Photo. Before autopsy, the top mat bent ECRs exhibit corrosion.
a) Top bars

Figure 67. Slab #8 extracted rebars condition. Photo. Before autopsy, all the straight bottom mat bars exhibit severe corrosion.
b) Bottom bars

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars

Figure 67. Slab #8 extracted rebars condition


Figure 68. Slab #8 after autopsy. Photo. After autopsy, the top mat bent ECRs are delaminated and severely corroded.
a) Top bars

Figure 68. Slab #8 after autopsy. Photo. After autopsy, the cleaned straight bottom mat black bars are severely pitted.
b) Bottom bars

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars

Figure 68. Slab #8 after autopsy


Figure 69. Slab #9 front, rear, and top views with specifications
Figure 69. Slab #9 front, rear, and top views with specifications. Photos. (A) Slab number 9 front view shows the 9B label on the left and 9A on the right. The bars are pale green and the concrete looks clear and with no cracks. Wires connect the top and bottom bars of 9B; the same is true for 9A.
a) Front View
Figure 69. Slab #9 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled showing the water dike with blue tape and some corrosion drips on the bottom bars.
b) Rear View
Figure 69. Slab #9 front, rear, and top views with specifications. Photos. (C) The top view is mottled gray with minor cracks.
c) Top View
d) Slab specifications
Specimen ID 9A 9B
Top mat Coating B Coating B
Bar shape (straight/bent) Straight Straight
Coating defect (%) 0.5 0.004
Bottom mat Coating B
Coating defect (%) 0.5 0.004
Precracked No No

Figure 70. Slab #9 extracted rebars condition. Photo. Before autopsy, the straight ECRs show good condition except that a top map ECR (A-T) shows major blistering and significant coating deterioration.

Figure 70. Slab #9 extracted rebars condition

Figure 71. Slab #9 after autopsy. Photo. After autopsy, a top mat ECR (A-T) is completely delaminated revealing severe corrosion of substrate, and the other top mat ECR (B-T) is still coated blue with one major delamination spot, but no corrosion underneath. The four bottom mat ECRs look good without coating deterioration.

Figure 71. Slab #9 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars


Figure 72. Slab #10 front, rear, and top views with specifications
Figure 72. Slab #10 front, rear, and top views with specifications. Photos. (A) Slab number 10 front view shows the 10B label on the left and 10A on the right. The green bars and the concrete looks clear, with no cracks with the water dike prominent. Wires connect the top and bottom bars of 10B and the same for 10A.
a) Front View
Figure 72. Slab #10 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled, showing minor corrosion drips from the middle to the bottom.
b) Rear View
Figure 72. Slab #10 front, rear, and top views with specifications. Photos. (C) The top view is mottled gray, with no visible cracks.
c) Top View
d) Slab specifications
Specimen ID 10A 10B
Top mat Coating A Coating A
Bar shape (straight/bent) Straight Straight
Coating defect (%) 0.5 0.004
Bottom mat Coating A
Coating defect (%) 0.5 0.004
Precracked No No

Figure 73. Slab #10 extracted rebars condition. Photo. Before autopsy, all straight top and bottom mat ECRs look good.

Figure 73. Slab #10 extracted rebars condition

Figure 74. Slab #10 after autopsy. Photo. After autopsy, a top mat ECR (A-T) is partially delaminated with minor substrate corrosion. The other five ECRs still look good.

Figure 74. Slab #10 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars


Figure 75. Slab #11 front, rear, and top views with specifications
Figure 75. Slab #11 front, rear, and top views with specifications. Photos. (A) Slab number 11 front view shows the 11B label on the left and 11A on the right. The green bars and the concrete look clear with no cracks but major corrosion shows around the top and third from left bottom bars. Wires connect the top and bottom bars of 11A and the bottom bars for 11A.
a) Front View
Figure 75. Slab #11 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled, showing the water dike with minor visible cracks.
b) Rear View
Figure 75. Slab #11 front, rear, and top views with specifications. Photos. (C) The top view is mottled gray with a few visible cracks.
c) Top View
d) Slab specifications
Specimen ID 11A 11B
Top mat Coating B Coating B
Bar shape (straight/bent) Bent Bent
Coating defect (%) 0.5 0.004
Bottom mat Black
Coating defect (%) N/A N/A
Precracked No No

Figure 76. Slab #11 extracted rebars condition. Photo. Before autopsy, the top mat two bent ECRs (A-T and B-T) exhibit moderate coating deterioration.
a) Top bars

Figure 76. Slab #11 extracted rebars condition. Photo. Before autopsy, the bottom mat four black bars look good.
b) Bottom bars

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars

Figure 76. Slab #11 extracted rebars condition


Figure 77. Slab #11 after autopsy. Photo. After autopsy, a top mat bent ECR (A-T) is completely delaminated while the other top mat bent ECR (B-T) is partially delaminated showing some substrate corrosion.
a) Top bars

Figure 77. Slab #11 after autopsy. Photo. After autopsy, the cleaned bottom mat four black bars look good.
b) Bottom bars

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars

Figure 77. Slab #11 after autopsy


Figure 78. Slab #12 front, rear, and top views with specifications
Figure 78. Slab #12 front, rear, and top views with specifications. Photos. (A) Slab number 12 front view shows the 12B label on the left and 12A on the right. The green bars and the concrete look clear, with one minor corroded crack. Wires connect the top and bottom bars of 12B; the same is true for 12A.
a) Front View
Figure 78. Slab #12 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled, showing minor discoloration but no visible cracks.
b) Rear View

Figure 78. Slab #12 front, rear, and top views with specifications. Photos. (C) The top view is severely mottled gray, with numerous visible cracks.
c) Top View
d) Slab specifications
Specimen ID 12A 12B
Top mat Coating C Coating C
Bar shape (straight/bent) Straight Straight
Coating defect (%) 0.5 0.004
Bottom mat Coating C
Coating defect (%) 0.5 0.004
Precracked No No

Figure 79. Slab #12 extracted rebars condition. Photo. Before autopsy, the top mat two ECRs (A-T and B-T) show corrosion induced coating deterioration.. All of the bottom mat ECRs show good coating condition.

Figure 79. Slab #12 extracted rebars condition

Figure 80. Slab #12 after autopsy. Photo. After autopsy, both top mat ECRs (A-T and B-T) are completely delaminated and reveal severely corroded substrates. The cleaned bottom mat four ECRs still look good without significant coating deterioration.

Figure 80. Slab #12 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars


Figure 81. Slab #13 front, rear, and top views with specifications
Figure 81. Slab #13 front, rear, and top views with specifications. Photos. (A) Slab number 13 front view shows the 13A label on the left and 13B on the right. The green bars and the concrete look clear with minor corrosion around the third on the bottom bar. Wires connect the top and bottom bars of 13B; the same is true for 13A.
a) Front View
Figure 81. Slab #13 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled showing the water dike and clear concrete with no corrosion.
b) Rear View
Figure 81. Slab #13 front, rear, and top views with specifications. Photos. (C) The top view is clear gray with the two precracks.
c) Top View
d) Slab specifications
Specimen ID 13A 13B
Top mat Coating C Coating C
Bar shape (straight/bent) Straight Straight
Coating defect (%) 0.5 0.004
Bottom mat Black
Coating defect (%) N/A N/A
Precracked Yes Yes

Figure 82. Slab #13 extracted rebars condition. Photo. Before autopsy, the top mat two straight ECRs (A-T and B-T) look good. The bottom mat four black bars are corrosion free except at the ends.

Figure 82. Slab #13 extracted rebars condition

Figure 83. Slab #13 after autopsy. Photo. After autopsy, a top mat ECR (A-T) is significantly (more than 40 percent) delaminated and corroded substrate is revealed, while the other top mat ECR (B-T) remains the same. The cleaned bottom mat four black bars look good.

Figure 83. Slab #13 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars


Figure 84. Slab #14 front, rear, and top views with specifications
Figure 84. Slab #14 front, rear, and top views with specifications. Photos. (A) Slab number 14 front view shows the 14A label on the left and 14B on the right. The green bars and the concrete have major cracks and corrosion around the bottom bars. Wires connect the top and bottom bars of 14B; the same is true for 14A.
a) Front View
Figure 84. Slab #14 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled showing cracks connecting the bottom bars and minor discoloration.
b) Rear View
Figure 84. Slab #14 front, rear, and top views with specifications. Photos. (C) The top view is clear gray with the two precracks, the right one showing some corrosion.
c) Top View
d) Slab specifications
Specimen ID 14A 14B
Top mat Coating E Coating E
Bar shape (straight/bent) Straight Straight
Coating defect (%) 0.004 0.5
Bottom mat Black
Coating defect (%) N/A N/A
Precracked Yes Yes

Figure 85. Slab #14 extracted rebars condition. Photo. Before autopsy, the top mat two ECRs (A-T and B-T) show blisters and some corrosion. The bottom mat four black bars (A-B1, A-B2, B-B1 and B-B2) are severely corroded.

Figure 85. Slab #14 extracted rebars condition

Figure 86. Slab #14 after autopsy. Photo. After autopsy, while a top mate ECR (A-T) exhibits minor corrosion with small coating disbondment, the other top mat ECR (B-T) suffers extensive coating deterioration and substrate corrosion. Most of the cleaned four bottom mat black bars exhibit severe corrosion damage.

Figure 86. Slab #14 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars


Figure 87. Slab #15 front, rear, and top views with specifications
Figure 87. Slab #15 front, rear, and top views with specifications. Photos. (A) Slab number 15 front view shows the 15A label on the left and 15B on the right. The green bars and the concrete look clear with no corrosion. Wires connect the top and bottom bars of 15B; the same is true for 15A.
a) Front View
Figure 87. Slab #15 front, rear, and top views with specifications. Photos. (B) The rear view is unlabeled showing clear concrete with no discoloration.
b) Rear View
Figure 87. Slab #15 front, rear, and top views with specifications. Photos. (C) The top view is clear gray with no discoloration.
c) Top View
d) Slab specifications
Specimen ID 15A 15B
Top mat Coating D Coating D
Bar shape (straight/bent) Straight Straight
Coating defect (%) 0.004 0.5
Bottom mat Black
Coating defect (%) N/A N/A
Precracked No No

Figure 88. Slab #15 extracted rebars condition. Photo. Before autopsy, the top mat two straight ECRs (A-T and B-T) look good other than intentional coating defects. The bottom mat straight black bars show corrosion-free condition.

Figure 88. Slab #15 extracted rebars condition

Figure 89. Slab #15 after autopsy. Photo. After autopsy, a top mat ECR (A-T) is unchanged without coating disbondment, but the other ECR (B-T) is moderately delaminated (more than 30 percent) with corroded substrate. The cleaned bottom mat black bars look good without pitting corrosion.

Figure 89. Slab #15 after autopsy

*A-T: Top left bar, B-T: Top right bar, A-B1&B2: Bottom left bars, B-B1&B2: Bottom right bars

 

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