Distress Identification Manual for The LTPP (Fourth Revised Edition)
Glossary
ADHESIVE FAILURE
loss of bond (e.g., between the joint sealant and the joint reservoir; between the aggregate and the binder)
AGGREGATE INTERLOCK
interaction of aggregate particles across cracks and joints to transfer load
APPROACH SLAB
section of pavement just prior to joint, crack, or other significant roadway feature relative to the direction of traffic (see also leave slab)
BINDER
brown or black adhesive material used to hold stones together for paving
BITUMINOUS
like or from asphalt
BLEEDING
identified by a film of bituminous material on the pavement surface that creates a shiny, glass-like, reflective surface that may be tacky to the touch in warm weather
BLOCK CRACKING
the occurrence of cracks that divide the asphalt surface into approximately rectangular pieces, typically 0.1 m2 or more in size
BLOWUP
the result of localized upward movement or shattering of a slab along a transverse joint or crack
CENTERLINE
the painted line separating traffic lanes
CHIPPING
breaking or cutting off small pieces from the surface
COHESIVE FAILURE
the loss of a material's ability to bond to itself. Results in the material splitting or tearing apart from itself (i.e., joint sealant splitting)
CONSTRUCTION JOINT
the point at which work is concluded and reinitiated when building a pavement
CORNER BREAK
a portion of a jointed concrete pavement separated from the slab by a diagonal crack intersecting the transverse and longitudinal joint, which extends down through the slab, allowing the corner to move independently from the rest of the slab
DURABILITY CRACKING
the breakup of concrete due to freeze-thaw expansive pressures within certain aggregates. Also called "D" cracking
EDGE CRACKING
fracture and materials loss in pavements without paved shoulders which occurs along the pavement perimeter. Caused by soil movement beneath the pavement
EXTRUSION
to be forced out (i.e., joint sealant from joint)
FATIGUE CRACKING
a series of small, jagged, interconnecting cracks caused by failure of the AC surface under repeated traffic loading (also called alligator cracking)
FAULT
difference in elevation between opposing sides of a joint or crack
FREE EDGE
pavement border that is able to move freely
HAIRLINE CRACK
a fracture that is very narrow in width, less than 3 mm
JOINT SEAL DAMAGE
any distress associated with the joint sealant, or lack of joint sealant
LANE LINE
boundary between travel lanes, usually a painted stripe
LANE-TO-SHOULDER DROPOFF
the difference in elevation between the traffic lane and shoulder
LANE-TO-SHOULDER SEPARATION
widening of the joint between the traffic lane and the shoulder
LEAVE SLAB
section of pavement just past a joint, crack, or other significant roadway feature relative to the direction of traffic
LONGITUDINAL
parallel to the centerline of the pavement
MAP CRACKING
a series of interconnected hairline cracks in PCC pavements that extend only into the upper surface of the concrete. Includes cracking typically associated with alkali-silica reactivity
PATCH
an area where the pavement has been removed and replaced with a new material
PATCH DETERIORATION
distress occurring within a previously repaired area
POLISHED AGGREGATE
surface mortar and texturing worn away to expose coarse aggregate in the concrete
POPOUTS
small pieces of pavement broken loose from the surface
POTHOLE
a bowl-shaped depression in the pavement surface
PUMPING
the ejection of water and fine materials through cracks in the pavement under moving loads
PUNCHOUT
a localized area of a CRCP bounded by two transverse cracks and a longitudinal crack. Aggregate interlock decreases over time and eventually is lost, leading to steel rupture and allowing the pieces to be punched down into the subbase and subgrade
RAVELING
the wearing away of the pavement surface caused by the dislodging of aggregate particles
REFLECTION CRACKING
the fracture of AC above joints in the underlying jointed concrete pavement layer(s)
RUTTING
longitudinal surface depressions in the wheelpaths
SCALING
the deterioration of the upper 3-12 mm of the concrete surface, resulting in the loss of surface mortar
SHOVING
permanent, longitudinal displacement of a localized area of the pavement surface caused by traffic pushing against the pavement
SPALLING
cracking, breaking, chipping, or fraying of the concrete slab surface within 0.6 m of a joint or crack
TRANSVERSE
perpendicular to the pavement centerline
WATER BLEEDING
seepage of water from joints or cracks
WEATHERING
the wearing away of the pavement surface caused by the loss of asphalt binder
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