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Publication Number: FHWA-RD-03-031
Date: JUNE 2003

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Distress Identification Manual for The LTPP (Fourth Revised Edition)

Chapter 1. Distresses for Pavements With Asphalt Concrete Surfaces

This section covers asphalt concrete-surfaced pavements (ACP), including ACP overlays on either asphalt concrete (AC) or portland cement concrete (PCC) pavements.

Each of the distresses has been grouped into one of the following categories:

  1. Cracking
  2. Patching and Potholes
  3. Surface Deformation
  4. Surface Defects
  5. Miscellaneous Distresses

Table 1 summarizes the various types of distress and unit of measurement. Some distresses also have defined severity levels.

 

TABLE 1. Asphalt Concrete-Surfaced Pavement Distress Types
DISTRESS TYPE
UNIT OF MEASURE
DEFINED SEVERITY LEVELS?
A.
1. Fatigue Cracking Square Square Meters Yes
2. Block Cracking Square Square Meters Yes
3. Edge Cracking Meters Yes
4a. Wheel Path Longitudinal Cracking Meters Yes
4b. Non-Wheel Path Longitudinal Cracking Meters Yes
5. Reflection Cracking at Joints
   Transverse Reflection Cracking
   Longitudinal Reflection Cracking
Not Measured
Not Measured
N/A
N/A
6. Transverse Cracking Number, Meters Yes

B.

7. Patch/Patch Deterioration Number, Square Meters Yes
8. Potholes Number, Square Meters Yes
C.
9. Rutting Millimeters No
10. Shoving Number, Square Meters No
D.
11. Bleeding Square Square Meters No
12. Polished Aggregate Square Meters No
13. Raveling Square Square Meters No
E.
14. Lane-to-Shoulder Dropoff Not Measured N/A
15. Water Bleeding and Pumping Number, Meters No

A. Cracking

This section includes the following distresses:

1. Fatigue Cracking
2. Block Cracking
3. Edge Cracking
4a. Longitudinal Cracking - Wheel Path
4b. Longitudinal Cracking - Non-Wheel Path
5. Reflection Cracking at Joints
6. Transverse Cracking

Measurement of crack width is illustrated in Figure 1. Figure 2 depicts the effect on severity level of a crack, in this case block cracking, due to associated random cracking.

FIGURE 1. Measuring Crack Width in Asphalt Concrete-Surfaced Pavements Schematic drawing of the procedure for measuring crack width in asphalt concrete-surfaced pavements.  The drawing shows two lanes of a pavement surface; the upper lane as it would be viewed in layers from the side, and the lower lane as it would be viewed from above with a dashed center line in the middle and edge stripe and shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The lane in the upper part of the drawing shows two cracks in the pavement, one of medium width and one of wider width.  The lane in the lower part of the drawing shows two cracks of narrower width.  Vertical lines and arrows at the widest point of the cracks in both lanes indicate the area that should be measured to determine crack width.

FIGURE 1
Measuring Crack Width in Asphalt Concrete-Surfaced Pavements

FIGURE 2.  Effect on Severity Level of Block Cracking due to Associated Random Cracking
Schematic drawing of the effect on severity level of block cracking due to associated random cracking in asphalt concrete-surfaced pavement.  The drawing shows one lane of a pavement surface as it would be viewed from above, with a dashed center line at the top and edge stripe and shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The drawing shows three block cracks in the pavement, one of moderate severity, one of low severity, and one of high severity.  The low severity block crack shows 3 vertical lines and 3 intersecting horizontal lines indicating cracks that form a pattern divided into 4 rectangular blocks.  In the moderate severity block crack, there is basically the same pattern, but there are 5 smaller lines perpendicular to the main lines of the crack indicating increased deterioration of the pavement surface.  In the high severity block crack, there are 17 smaller lines perpendicular to the main lines of the crack indicating even more deterioration of the pavement surface.

FIGURE 2
Effect on Severity Level of Block Cracking due to Associated Random Cracking

 

1. FATIGUE CRACKING

Description

Occurs in areas subjected to repeated traffic loadings (wheel paths). Can be a series of interconnected cracks in early stages of development. Develops into many-sided, sharp-angled pieces, usually less than 0.3 meters (m) on the longest side, characteristically with a chicken wire/alligator pattern, in later stages.

Must have a quantifiable area.

Severity Levels

LOW
An area of cracks with no or only a few connecting cracks; cracks are not spalled or sealed; pumping is not evident.

MODERATE
An area of interconnected cracks forming a complete pattern; cracks may be slightly spalled; cracks may be sealed; pumping is not evident.

HIGH
An area of moderately or severely spalled interconnected cracks forming a complete pattern; pieces may move when subjected to traffic; cracks may be sealed; pumping may be evident.

How to Measure

Record square meters of affected area at each severity level. If different severity levels existing within an area cannot be distinguished, rate the entire area at the highest severity present.

FIGURE 3.  Distress Type ACP 1 - Fatigue Cracking Schematic drawing of asphalt concrete pavement with distress type ACP 1 - fatigue cracking.  The drawing shows one lane of a pavement surface as it would be viewed from above, with a dashed center line at the top and edge stripe and shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The drawing shows three fatigue cracks in the pavement, one of moderate severity, one of high severity, and one of low severity.  The low severity fatigue crack shows a row of 6 lines in the wheel path closest to the shoulder indicating cracks that are close together but not interconnected.  In the moderate severity fatigue crack, there are 10 interconnected lines in the wheel path closest to the center line indicating cracks of the pavement surface.  In the high severity fatigue crack, there are 30 or more  lines in the wheel path closest to the center line that completely interconnect to form a many-sided, sharp-angled pattern indicating increased deterioration of the pavement surface.

FIGURE 3
Distress Type ACP 1 - Fatigue Cracking

FIGURE 4.  Distress Type ACP 1 - Chicken Wire/Alligator Pattern Cracking Typical in Fatigue Cracking Color photograph of asphalt concrete pavement with distress type ACP 1 - chicken wire/alligator pattern cracking typical in fatigue cracking.  The picture shows an area of  pavement with numerous intersecting cracks that form a pattern of small shapes similar to that of chicken wire or alligator skin.  This pattern is typical in fatigue cracking.
FIGURE 4
Distress Type ACP 1 - Chicken Wire/Alligator Pattern Cracking Typical in Fatigue Cracking
FIGURE 5.  Distress Type ACP 1 - Low Severity Fatigue Cracking Color photograph of asphalt concrete pavement with distress type ACP 1 - low severity fatigue cracking.  Cracking, some interconnected, is visible in the both wheel paths over the length of the lane pictured.
FIGURE 5
Distress Type ACP 1 - Low Severity Fatigue Cracking
FIGURE 6.  Distress Type ACP 1 - Moderate Severity Fatigue Cracking Color photograph of asphalt concrete pavement with distress type ACP 1 - moderate severity fatigue cracking.  The cracking is visible along the wheel path closest to the edge stripe, and its size is approximately 500 mm wide as indicated by the 500-mm scale pictured in the center of the photograph.
FIGURE 6

Distress Type ACP 1 - Moderate Severity Fatigue Cracking
FIGURE 7.  Distress Type ACP 1 - High Severity Fatigue Cracking with Spalled Interconnected Cracks, Color photograph of asphalt concrete pavement with distress type ACP 1 - high severity fatigue cracking with spalled interconnected cracks.  The cracking is visible along the wheel path closest to the edge stripe, and its size is approximately 600 mm wide as indicated by the 500-mm scale pictured in the center of the photograph.
FIGURE 7

Distress Type ACP 1 - High Severity Fatigue Cracking with Spalled Interconnected Cracks

2. BLOCK CRACKING

Description

A pattern of cracks that divides the pavement into approximately rectangular pieces. Rectangular blocks range in size from approximately 0.1 m2 to 10 m2.

Severity Levels

LOW
Cracks with a mean width £ 6 millimeters (mm); or sealed cracks with sealant material in good condition and with a width that cannot be determined.

MODERATE
Cracks with a mean width > 6 mm and £ 19 mm; or any crack with a mean width £ 19 mm and adjacent low severity random cracking.

HIGH
Cracks with a mean width > 19 mm; or any crack with a mean width £ 19 mm and adjacent moderate to high severity random cracking.

How to Measure

Record square meters of affected area at each severity level. If fatigue cracking exists within the block cracking area, the area of block cracking is reduced by the area of fatigue cracking.

Note: An occurrence should be at least 15 m long before rating as block cracking.

FIGURE 8.  Distress Type ACP 2 - Block Cracking, Schematic drawing of asphalt concrete pavement with distress type ACP 2 - block cracking.  The drawing shows one lane of a pavement surface as it would be viewed from above, with a dashed center line at the top and a shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The drawing shows two areas of block cracking in the pavement; both cover approximately the same area, 3 m wide and 3 m long, but are at different severity levels.  The lower severity block crack shows 2 vertical lines that are 3 m apart and 2 intersecting horizontal lines that are 3 m apart that indicate cracks forming a pattern of one rectangular block.  In the higher severity block crack, there are 5 vertical lines that are approximately 0.3 m apart and 5 intersecting horizontal lines that are approximately 0.3 m apart indicating cracks that form a pattern of 16 rectangular blocks.

FIGURE 8
Distress Type ACP 2 - Block Cracking

FIGURE 9.  Distress Type ACP 2 - Block Cracking with Fatigue Cracking in the Wheel Paths
Color photograph of asphalt concrete pavement with distress type ACP 2 - block cracking with fatigue cracking in the wheel paths.  The fatigue cracking is approximately 500 mm wide for the entire length of the lane in both wheel paths, and is connected to block cracking that is approximately 500 mm wide outside each wheel path and 1000 mm between the wheel paths, as indicated by the 500-mm scale pictured in the center of the photograph.

FIGURE 9
Distress Type ACP 2 - Block Cracking with Fatigue Cracking in the Wheel Paths

FIGURE 10.  Distress Type ACP 2 - High Severity Block Cracking, Color photograph of asphalt concrete pavement with distress type ACP 2 - high severity block cracking in the wheel path of the lane closest to the center line.  A pattern of more than 15 rectangular blocks is formed by the intersecting cracks.

FIGURE 10
Distress Type ACP 2 - High Severity Block Cracking

3. EDGE CRACKING

Description

Applies only to pavements with unpaved shoulders. Crescent-shaped cracks or fairly continuous cracks which intersect the pavement edge and are located within 0.6 m of the pavement edge, adjacent to the shoulder. Includes longitudinal cracks outside of the wheel path and within 0.6 m of the pavement edge.

Severity Levels

LOW
Cracks with no breakup or loss of material.

MODERATE
Cracks with some breakup and loss of material for up to 10 percent of the length of the affected portion of the pavement.

HIGH
Cracks with considerable breakup and loss of material for more than 10 percent of the length of the affected portion of the pavement.

How to Measure

Record length in meters of pavement edge affected at each severity level. The combined quantity of edge cracking cannot exceed the length of the section.

FIGURE  11 Distress Type ACP 3 - Edge Cracking, Schematic drawing of asphalt concrete pavement with distress type ACP 3 - edge cracking in pavement.  The drawing shows one lane of a pavement surface as it would be viewed from above, with a dashed center line at the top and an edge stripe and unpaved shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The drawing shows three areas of edge cracking in the pavement; the three occupy approximately the same area, 0.6 m wide, at a low severity level.  The first edge crack shows 3 almost parallel lines indicating cracks between the unpaved shoulder and the edge stripe.  The second edge crack shows 4 interconnected lines indicating cracks between the unpaved shoulder and the edge stripe.  The third edge crack shows one wavy line indicating a crack at the edge of the lane very close to the edge stripe.

FIGURE 11
Distress Type ACP 3 - Edge Cracking

FIGURE 12.  Distress Type ACP 3 - Low Severity Edge Cracking, Color photograph of asphalt concrete pavement with distress type ACP 3 - low severity edge cracking.  The width of the cracking is approximately 400 m as indicated by the 500-mm scale pictured in the center of the photograph, starting at the unpaved shoulder and ending beyond the edge stripe, and extending along the entire length of the lane.

FIGURE 12
Distress Type ACP 3 - Low Severity Edge

 

4. LONGITUDINAL CRACKING

Description

Cracks predominantly parallel to pavement centerline. Location within the lane (wheel path versus non-wheel path) is significant.

Severity levels

LOW
A crack with a mean width £6 mm; or a sealed crack with sealant material in good condition and with a width that cannot be determined.

MODERATE
Any crack with a mean width > 6 mm and £ 19 mm; or any crack with a mean width £ 19 mm and adjacent low severity random cracking.

HIGH
Any crack with a mean width > 19 mm; or any crack with a mean width £ 19 mm and adjacent moderate to high severity random cracking.

FIGURE 13.  Distress Type ACP 4 - Longitudinal Cracking, Schematic drawing of asphalt concrete pavement with distress type ACP 4 - longitudinal cracking.  The drawing shows one lane of a pavement surface as it would be viewed from above, with a dashed center line at the top and an edge stripe and paved shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The drawing shows a continuous longitudinal crack between the inner wheel path and the center line that extends along approximately half of the length of the lane.  There is a continuous longitudinal crack in the middle of the inner wheel path that extends along approximately a quarter of the length of the lane.  Between the inner and outer wheel paths, there is a continuous longitudinal crack in the middle of the lane that extends along approximately a third of the length of the lane.  There is  also a continuous longitudinal crack in the middle of the outer wheel path that extends along approximately a quarter of the length of the lane.  Finally, there is a continuous longitudinal crack between the outer wheel path and the center line that extends along approximately a third of the length of the lane.

FIGURE 13
Distress Type ACP 4 - Longitudinal Cracking

 

How to Measure

Record separately:

4A. WHEEL PATH LONGITUDINAL CRACKING

Record the length in meters of longitudinal cracking within the defined wheel paths at each severity level.

Record the length in meters of longitudinal cracking with sealant in good condition at each severity level.

Note: Any wheel path longitudinal crack that has associated random cracking is rated as fatigue cracking. Any wheel path longitudinal crack that meanders and has a quantifiable area is rated as fatigue cracking.

4B. NON-WHEEL PATH LONGITUDINAL CRACKING

Record the length in meters of longitudinal cracking not located in the defined wheel paths at each severity level.

Record the length in meters of longitudinal cracking with sealant in good condition at each severity level.

FIGURE 14.  Distress Type ACP 4a - Moderate Severity Longitudinal Cracking in the Wheel Path, Color photograph of asphalt concrete pavement with distress type ACP 4a - moderate severity longitudinal cracking in the wheel path.  As indicated by the 500-mm scale pictured in the center of the photograph, the crack is approximately 18 mm wide, and extends through the outer wheel path along the entire length of the lane.

FIGURE 14
Distress Type ACP 4a - Moderate Severity Longitudinal Cracking in the Wheel Path

FIGURE 15.  Distress Type ACP 4b - High Severity Longitudinal Cracking Not in the Wheel Path, Color photograph of asphalt concrete pavement with distress type ACP 4b - high severity longitudinal cracking not in the wheel path.  As indicated by the 500-mm scale pictured in the center of the photograph, the crack is approximately 25 mm wide, and extends from the inner wheel path toward the center line along the entire length of the lane.

FIGURE 15
Distress Type ACP 4b - High Severity Longitudinal Cracking not in the Wheel Path

 

5. REFLECTION CRACKING AT JOINTS

Description

Cracks in asphalt concrete overlay surfaces that occur over joints in concrete pavements.

Note: The slab dimensions beneath the AC surface must be known to identify reflection cracks at joints.

Severity Levels

LOW
An unsealed crack with a mean width £ 6 mm; or a sealed crack with sealant material in good condition and with a width that cannot be determined.

MODERATE
Any crack with a mean width > 6 mm and £ 19 mm; or any crack with a mean width £ 19 mm and adjacent low severity random cracking.

HIGH
Any crack with a mean width > 19 mm; or any crack with a mean width £ 19 mm and adjacent moderate to high severity random cracking.

FIGURE 16.  Distress Type ACP 5 - Reflection Cracking at Joints, Schematic drawing of asphalt concrete pavement with distress type ACP 5 - reflection cracking at joints.  The drawing shows two lanes of a pavement surface; the upper lane as it would be viewed in layers from the side, and the lower lane as it would be viewed from above with a dashed center line in the middle and edge stripe and shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The lane in the upper part of the drawing shows three cracks in the pavement.  Two are joint reflection cracks of the asphalt concrete overlay; one of medium width and penetrating to approximately half the depth of the overlay, the other is wider and penetrates the entire depth of the overlay.  The third crack is a transverse crack that penetrates the entire depth of both the asphalt concrete overlay and the original jointed concrete pavement layer.  The lane in the lower part of the drawing shows three transverse reflected cracks that cross the entire width of the lane, and a series of longitudinal joint reflection cracks along the entire length of the center line.  It is noted that uniform spacing of cracks reflects the spacing of underlying joints.

FIGURE 16
Distress Type ACP 5 - Reflection Cracking at Joints

 

How to Measure

Recorded as longitudinal cracking (ACP4) or transverse cracking (ACP6) on LTPP surveys.

FIGURE 17.   Distress Type ACP 5 - High Severity Reflection Cracking at Joints, Color photograph of asphalt concrete pavement with distress type ACP 5 - high severity reflection cracking at joints. The photo shows five uniformly spaced joint reflection cracks across the entire width of the lane and longitudinal joint cracking along the entire length of the center line.

FIGURE 17
Distress Type ACP 5 - High Severity Reflection Cracking at Joints

 

6. TRANSVERSE CRACKING

Description

Cracks that are predominantly perpendicular to pavement centerline.

Severity Levels

LOW
An unsealed crack with a mean width £ 6 mm; or a sealed crack with sealant material in good condition and with a width that cannot be determined.

MODERATE
Any crack with a mean width > 6 mm and £ 19 mm; or any crack with a mean width £ 19 mm and adjacent low severity random cracking.

HIGH
Any crack with a mean width > 19 mm; or any crack with a mean width £ 19 mm and adjacent moderate to high severity random cracking.

 

FIGURE 18.  Distress Type ACP 6 - Transverse Cracking, Schematic drawing of asphalt concrete pavement with distress type ACP 6 - transverse cracking.  The drawing shows one lane of a pavement surface as it would be viewed from above, with a dashed center line at the top and edge stripe and shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The drawing shows four transverse cracks in the pavement, two of low severity, one of moderate severity, and one of high severity.  The low severity transverse cracks show crack widths of 3 mm and 5 mm, respectively, and extend through approximately one-half to one-third of the lane.  The moderate severity transverse crack varies in width from 4 mm to 12 mm, and crosses the entire lane with the 12-mm crack width extending through approximately one-quarter of the total length of the crack.  The high severity block crack varies in width from 4 mm to 20 mm, and crosses the entire lane with the 20-mm crack width extending through approximately two-thirds of the total length of the crack.  There is a note to rate the entire crack at the highest level for 10 percent or more of the total crack length.

FIGURE 18
Distress Type ACP 6 - Transverse Cracking Asphalt Concrete Surfaces

How to Measure

Record number and length of transverse cracks at each severity level. Rate the entire transverse crack at the highest severity level present for at least 10 percent of the total length of the crack. Length recorded, in meters, is the total length of the crack and is assigned to the highest severity level present for at least 10 percent of the total length of the crack.

Also record length in meters of transverse cracks with sealant in good condition at each severity level.

Note: The length recorded is the total length of the well-sealed crack and is assigned to the severity level of the crack. Record only when the sealant is in good condition for at least 90 percent of the length of the crack.

If the transverse crack extends through an area of fatigue cracking, the length of the crack within the fatigue area is not counted. The crack is treated as a single transverse crack, but at a reduced length.

Cracks less than 0.3 m in length are not recorded.

 

FIGURE 19.  Distress Type ACP 6 - Low Severity Transverse Cracking, Color photograph of asphalt concrete pavement with distress type ACP 6 - low severity transverse cracking.  The narrow crack extends across approximately 90 percent of the lane, ending just inside the edge stripe.

FIGURE 19
Distress Type ACP 6 - Low Severity Transverse Cracking

FIGURE 20.  Distress Type ACP 6 - Moderate Severity Transverse Cracking, Color photograph of asphalt concrete pavement with distress type ACP 6 - moderate severity transverse cracking.  As indicated by the 500-mm scale pictured in the center of the photograph, the crack width varies from approximately 10 mm to 15 mm, and extends across approximately 80 percent of the lane.

FIGURE 20
Distress Type ACP 6 - Moderate Severity Transverse Cracking

FIGURE 21.  Distress Type ACP 6 - High Severity Transverse Cracking, Color photograph of asphalt concrete pavement with distress type ACP 6 - high severity transverse cracking.  The deep, uneven crack extends across the entire road from the unpaved shoulder to the opposite unpaved shoulder.  As indicated by the 500-mm scale pictured in the center of the photograph, the crack width varies between approximately 25 mm and 50 mm.

FIGURE 21
Distress Type ACP 6 - High Severity Transverse Cracking

 

B. Patching and Potholes

This section includes the following distresses:

7. Patch/Patch Deterioration
8. Potholes

7. PATCH/PATCH DETERIORATION

Description

Portion of pavement surface, greater than 0.1 m2, that has been removed and replaced or additional material applied to the pavement after original construction.

Severity Levels

LOW
Patch has, at most, low severity distress of any type including rutting < 6 mm; pumping is not evident.

MODERATE
Patch has moderate severity distress of any type or rutting from 6 mm to 12 mm; pumping is not evident.

HIGH
Patch has high severity distress of any type including rutting > 12 mm, or the patch has additional different patch material within it; pumping may be evident.

How to Measure

Record number of patches and square meters of affected surface area at each severity level.

Note: Any distress in the boundary of the patch is included in rating the patch. Rutting (settlement) may be at the perimeter or interior of the patch.

 

FIGURE 22.  Distress Type ACP 7 - Patch/Patch Deterioration, Schematic drawing of asphalt concrete pavement with distress type ACP 7 - patch/patch deterioration.  The drawing shows one lane of a pavement surface as it would be viewed from above, with a dashed center line at the top and edge stripe and shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The drawing shows three patches in the pavement.  The first patch extends for the entire length of the lane through the wheel path closest to the center line, and raises the rut level.  The second patch extends for approximately one-third the length of the lane in a L-shape in the wheel path closest to the shoulder.  The third patch is an irregular oval shape that is approximately one-tenth the length of the lane in the wheel path closest to the shoulder.  There is also a 0.05-square m area of road deterioration near the shoulder that has no patch

FIGURE 22
Distress Type ACP 7 - Patch/Patch Deterioration

FIGURE 23.  Distress Type ACP 7 - Low Severity Patch, Color photograph of asphalt concrete pavement with distress type ACP 7 - low severity patch.  The large rectangular patch extends across one entire lane of a four-lane highway and shows no visible deterioration

FIGURE 23
Distress Type ACP 7 - Low Severity Patch

FIGURE 24.  Distress Type ACP 7 - Low Severity Patch, Color photograph of asphalt concrete pavement with distress type ACP 7 - low severity patch.  The large rectangular patch extends across one lane of a two-lane highway from the edge of the road to the middle of the inner wheel path and shows no visible deterioration.  The width of the patch is approximately 2 m and the length is approximately 2 m, as indicated by the 500-mm scale near the center of the photograph.

FIGURE 24
Distress Type ACP 7 - Moderate Severity Patch

FIGURE 25.  Distress Type ACP 7 - High Severity Patch, Color photograph of asphalt concrete pavement with distress type ACP 7 - high severity patch.   The patched area is located near the shoulder and contains two large patches that are generally round in shape and appear to be potholes that were repaired. There is extensive cracking and deterioration within and surrounding the patches.

FIGURE 25
Distress Type ACP 7 - High Severity Patch

8. POTHOLES

Description

Bowl-shaped holes of various sizes in the pavement surface. Minimum plan dimension is 150 mm.

Severity Levels

LOW
< 25 mm deep.

MODERATE
25 mm to 50 mm deep.

HIGH
> 50 mm deep.

How to Measure

Record number of potholes and square meters of affected area at each severity level. Pothole depth is the maximum depth below pavement surface. If pothole occurs within an area of fatigue cracking the area of fatigue cracking is reduced by the area of the pothole.

FIGURE 26.  Distress Type ACP 8 - Potholes, Schematic drawing of asphalt concrete pavement with distress type ACP 8 - potholes.  The drawing shows two lanes of a pavement surface; the upper lane as it would be viewed in depth across the width of the lane, and the lower lane as it would be viewed from above with a dashed center line in the middle and edge stripe and shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The lane in the upper part of the drawing shows three potholes in the outer wheel path of the pavement, of varying depth and width. Dashed lines and arrows at the deepest point of two of the potholes indicate that this is the area that should be measured to determine pothole depth.  The lane in the lower part of the drawing shows the three potholes in the outer wheel path and shows a size measurement of 100 mm for the smallest of the three potholes.  There is a note indicating that the depth of the third pothole is not measured because its size is less than the minimum dimension of 150 mm.

FIGURE 26
Distress Type ACP 8 - Potholes

FIGURE 27.  Distress Type ACP 8 - Low Severity Pothole, Color photograph of asphalt concrete pavement with distress type ACP 8 - low severity pothole. The area of deterioration is approximately 500 mm wide as indicated by the scale pictured in the center of the photograph, and the pothole forming is approximately 200 mm wide and 25mm deep.

FIGURE 27
Distress Type ACP 8 - Low Severity Pothole

FIGURE 28.  Distress Type ACP 8 - Moderate Severity Pothole, Color photograph of asphalt concrete pavement with distress type ACP 8 - moderate severity pothole.  The area of deterioration near the center line is a bowl-shaped hole in the pavement surface with cracking around its edges.

FIGURE 28
Distress Type ACP 8 - Moderate Severity Pothole

FIGURE 29.  Distress Type ACP 8 - Moderate Severity Pothole, Close-up View, Color photograph of asphalt concrete pavement with distress type ACP 8 - moderate severity pothole, close-up view.  The area of deterioration as viewed from above is a bowl-shaped hole in the pavement containing loosened aggregate.

FIGURE 29
Distress Type ACP 8 - Moderate Severity Pothole, Close-up View

FIGURE 30.  Distress Type ACP 8 - High Severity Pothole, Close up View, Color photograph of asphalt concrete pavement with distress type ACP 8 - high severity pothole, close-up view. The area of deterioration is a deep bowl-shaped hole in the pavement containing water and is severely cracked around its edges.

FIGURE 30
Distress Type ACP 8 - High Severity Pothole, Close-up View

C. Surface Deformation

This section includes the following types of surface deformations:

9. Rutting
10. Shoving

 

9. RUTTING

Description

A rut is a longitudinal surface depression in the wheel path. It may have associated transverse displacement.

Severity Levels

Not applicable. Severity levels could be defined by categorizing the measurements taken. A record of the measurements taken is much more desirable, because it is more accurate and repeatable than are severity levels.

How to Measure

Specific Pavement Studies (SPS)-3 ONLY. Record maximum rut depth to the nearest millimeter, at 15.25-m intervals for each wheel path, as measured with a 1.2-m straight edge.

All other LTPP sections: Transverse profile is measured with a Dipstick® profiler at 15.25-m intervals.

FIGURE 31.  Distress Type ACP 9 - Rutting, Schematic drawing of asphalt concrete pavement with distress type ACP 9 - rutting in pavement.  The drawing shows two lanes of a pavement surface; the upper lane as it would be viewed in depth across the width of the lane, and the lower lane as it would be viewed from above with a dashed center line in the middle and edge stripe and shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The lane in the upper part of the drawing shows two ruts in the wheel path of the pavement, of approximately the same depth. Dashed lines and arrows at the deepest point of the ruts indicate that this is the area that should be measured to determine rut depth.  The lane in the lower part of the drawing shows the area from just beyond the center line to the shoulder where the two ruts are measured.

FIGURE 31
Distress Type ACP 9 - Rutting

FIGURE 32.  Distress Type ACP 9 - Rutting, Color photograph of asphalt concrete pavement with distress type ACP 9 -  rutting.  The photo shows a 1.83 m (6-ft.) Straightedge measure placed across a wheel path in the pavement and the rut is indicated by the space visible underneath the stick.  The width of the rut is approximately 1 m.

FIGURE 32
Distress Type ACP 9 - Rutting

FIGURE 33.  Distress Type ACP 9 - Standing Water in Ruts, Color photograph of asphalt concrete pavement with distress type ACP 9 - standing water in ruts.  The photo shows one lane of a two-lane road where water has collected in ruts in the wheel paths along the entire length of the road visible in the photograph.

FIGURE 33
Distress Type ACP 9 - Standing Water in Ruts

 

10. SHOVING

Description

Shoving is a longitudinal displacement of a localized area of the pavement surface. It is generally caused by braking or accelerating vehicles, and is usually located on hills or curves, or at intersections. It also may have associated vertical displacement.

Severity Levels

Not applicable. However, severity levels can be defined by the relative effect of shoving on ride quality.

How to Measure

Record number of occurrences and square meters of affected surface area.

FIGURE 34.  Distress Type ACP 10 - Shoving, Schematic drawing of asphalt concrete pavement with distress type ACP 10 - shoving.  The drawing shows two lanes of a pavement surface; the upper lane as it would be viewed in depth along the length of the lane, and the lower lane as it would be viewed from above with a dashed center line in the middle and edge stripe and shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The lane in the upper part of the drawing shows two areas of shoving in the wheel path of the pavement, of approximately the same vertical displacement.  Vertical lines and arrows at the highest point of the vertical displacement indicate that this is the area that should be measured to determine shoving severity.  The lane in the lower part of the drawing shows four areas of shoving in the wheel paths in the middle section of the lane.

FIGURE 34
Distress Type ACP 10 - Shoving

FIGURE 35.  Distress Type ACP 10 - Shoving in Pavement Surface, Color photograph of asphalt concrete pavement with distress type ACP 10 - shoving in pavement surface.  Four areas of vertical displacement of the pavement surface are visible across the length of the photo.

FIGURE 35
Distress Type ACP 10 - Shoving in Pavement Surface

 

D. Surface Defects

This section includes the following types of surface defects:

11. Bleeding
12. Polished Aggregate
13. Raveling

 

11. BLEEDING

Description

Excess bituminous binder occurring on the pavement surface, usually found in the wheel paths. May range from a surface discolored relative to the remainder of the pavement, to a surface that is losing surface texture because of excess asphalt, to a condition where the aggregate may be obscured by excess asphalt possibly with a shiny, glass-like, reflective surface that may be tacky to the touch.

Severity Levels

Not applicable. The presence of bleeding indicates potential mixture related performance problems. Extent is sufficient to monitor any progression.

How to Measure

Record square meters of surface area affected.

Note: Preventative maintenance treatments (slurry seals, chip seals, fog seals, etc.) sometimes exhibit bleeding characteristics. These occurrences should be noted, but not rated as bleeding.

FIGURE 36.  Distress Type ACP 11 - Discoloration, Color photograph of asphalt concrete pavement with distress type ACP 11 - discoloration.  The discolored surface of the wheel paths along the length of the lane indicates low level bleeding of excess bituminous binder.  A 500-mm scale is pictured in the center of the photograph, and indicates that the lane is approximately 2500 mm long.

FIGURE 36
Distress Type ACP 11 - Discoloration

FIGURE 37.  Distress Type ACP 11 - Loss of Texture, Color photograph of asphalt concrete pavement with distress type ACP 11 - loss of texture.  Black discolored wheel paths on the pavement show a loss of surface texture because of excess asphalt along the length of the lane indicating moderate level bleeding.  A 500-mm scale is pictured in the center of the photograph, and indicates that the area of the lane that is depicted is approximately 2500 mm long.

FIGURE 37
Distress Type ACP 11 - Loss of Texture

FIGURE 38.  Distress Type ACP 11 - Aggregate Obscured, Color photograph of asphalt concrete pavement with distress type ACP 11 - aggregate obscured.  The aggregate in the pavement is obscured by excess asphalt with a shiny, glass-like, reflective surface that has become tacky as indicated by a tire mark on the surface.  This high level bleeding is more evident during warm weather.

FIGURE 38
Distress Type ACP 11 - Aggregate Obscured

 

12. POLISHED AGGREGATE

Description

Surface binder worn away to expose coarse aggregate.

Severity Levels

Not applicable. However, the degree of polishing may be reflected in a reduction of surface friction.

How to Measure

Record square meters of affected surface area. Polished aggregate should not be rated on test sections that have received a preventive maintenance treatment that has covered the original pavement surface.

FIGURE 39.  Distress Type ACP 12 - Polished Aggregate, Color photograph of asphalt concrete pavement with distress type ACP 12 - polished aggregate.  The photo shows a pavement surface in which the binder has worn away to expose coarse aggregate.

FIGURE 39
Distress Type ACP 12 - Polished Aggregate

 

13. RAVELING

Description

Wearing away of the pavement surface caused by the dislodging of aggregate particles and loss of asphalt binder. Raveling ranges from loss of fines to loss of some coarse aggregate and ultimately to a very rough and pitted surface with obvious loss of aggregate.

Severity Levels

Not applicable. The presence of raveling indicates potential mixture related performance problems. Extent is sufficient to monitor any progression.

How to Measure

Record square meters of affected surface. Raveling should not be rated on chip seals.

FIGURE 40.  Distress Type ACP 13 - Loss of Fine Aggregate, Color photograph of asphalt concrete pavement with distress type ACP 13 - loss of fine aggregate.  The photo shows a pavement surface that has begun to wear away but has not progressed significantly.  Some loss of fine aggregate caused by loss of the asphalt binder effects the entire area pictured, which is approximately 1000 mm wide and 600 mm long as indicated by the 500-mm scale pictured in the center of the photograph.

FIGURE 40
Distress Type ACP 13 - Loss of Fine Aggregate

FIGURE 41.  Distress Type ACP 13 - Loss of Fine and Some Coarse Aggregate, Color photograph of asphalt concrete pavement with distress type ACP 13 - loss of fine and some coarse aggregate.  The photo shows a pavement surface that has become rough and pitted, and includes loose particles of dislodged aggregate.  There is loss of fine and some coarse aggregate caused by deterioration of the asphalt binder that affects the entire area pictured.

FIGURE 41
Distress Type ACP 13 - Loss of Fine and Some Coarse Aggregate

FIGURE 42.  Distress Type ACP 13 - Loss of Coarse Aggregate, Color photograph of asphalt concrete pavement with distress type ACP 13 - loss of coarse aggregate.  The photo shows a pavement surface that has become very rough and pitted, and includes loose particles of dislodged coarse aggregate.  The loss of coarse aggregate caused by the deterioration of fine aggregate and asphalt binder effects the entire area pictured, which is approximately 500 mm wide and 250 mm long as indicated by the 500-mm scale pictured in the center of the photograph.

FIGURE 42
Distress Type ACP 13 - Loss of Coarse Aggregate

 

E. Miscellaneous Distresses

This section includes the following distresses:

14. Lane-to-Shoulder Dropoff
15. Water Bleeding and Pumping

 

14. LANE-TO-SHOULDER DROPOFF

Description

Difference in elevation between the traveled surface and the outside shoulder. Typically occurs when the outside shoulder settles as a result of pavement layer material differences.

Severity Level

Not applicable. Severity levels could be defined by categorizing the measurements taken. A record of the measurements taken is much more desirable, however, because it is more accurate and repeatable than are severity levels.

How to Measure

Not recorded in LTPP surveys.

FIGURE 43.  Distress Type ACP 14 - Lane-to-Shoulder Dropoff, Schematic drawing of asphalt concrete pavement with distress type ACP 14 - lane-to-shoulder dropoff.  The drawing shows two lanes of a pavement surface; the upper lane as it would be viewed in depth from the wheel path of the lane to the end of the shoulder, and the lower lane as it would be viewed from above with a dashed center line in the middle and edge stripe and shoulder at the bottom.  An arrow indicates that the traffic moves toward the right side of the drawing.  The lane in the lower part of the drawing shows the area of the lane from the wheel path to the shoulder that should be measured.   The lane in the upper part of the drawing shows the difference in elevation between the lane and the shoulder.  Vertical lines and arrows at the lane level and at the shoulder level indicate the area that should be measured to determine lane-to-shoulder dropoff.

FIGURE 43
Distress Type ACP 14 - Lane-to-Shoulder Dropoff

FIGURE 44.  Distress Type ACP 14 - Lane-to-Shoulder Dropoff, Color photograph of asphalt concrete pavement with distress type ACP 14 - lane-to-shoulder dropoff.  The photo shows a measuring stick placed across the edge of the lane and the shoulder, and the dropoff is indicated by the space visible underneath the stick at the shoulder end.

FIGURE 44
Distress Type ACP 14 - Lane-to-Shoulder Dropoff

15. WATER BLEEDING AND PUMPING

Description

Seeping or ejection of water from beneath the pavement through cracks. In some cases, detectable by deposits of fine material left on the pavement surface, which were eroded (pumped) from the support layers and have stained the surface.

Severity Levels

Not applicable. Severity levels are not used because the amount and degree of water bleeding and pumping changes with varying moisture conditions.

How to Measure

Record the number of occurrences of water bleeding and pumping and the length in meters of affected pavement with a minimum length of 1 m.

Note. The combined length of water bleeding and pumping cannot exceed the length of the test section.

FIGURE 45.  Distress Type ACP 15 - Water Bleeding and Pumping, Color photograph of asphalt concrete pavement with distress type ACP 15 - water bleeding and pumping.  The photo show a pavement surface with intersecting transverse and longitudinal cracks that has been stained by water that has seeped through the cracks from beneath the pavement.

FIGURE 45
Distress Type ACP 15 - Water Bleeding and Pumping

FIGURE 46.  Distress Type ACP 15 - Fine Material Left on Surface by Water Bleeding and Pumping, Color photograph of asphalt concrete pavement with distress type ACP 15 - fine material left on surface by water bleeding and pumping.  The photo shows a lane of highway with two transverse cracks that have been stained by water and fine material that has seeped through the cracks from beneath the pavement.

FIGURE 46
Distress Type ACP 15 - Fine Material Left on Surface by Water Bleeding and Pumping

 

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The Federal Highway Administration (FHWA) is a part of the U.S. Department of Transportation and is headquartered in Washington, D.C., with field offices across the United States. is a major agency of the U.S. Department of Transportation (DOT).
The Federal Highway Administration (FHWA) is a part of the U.S. Department of Transportation and is headquartered in Washington, D.C., with field offices across the United States. is a major agency of the U.S. Department of Transportation (DOT). Provide leadership and technology for the delivery of long life pavements that meet our customers needs and are safe, cost effective, and can be effectively maintained. Federal Highway Administration's (FHWA) R&T Web site portal, which provides access to or information about the Agency’s R&T program, projects, partnerships, publications, and results.
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United States Department of Transportation - Federal Highway Administration