PAVEMENT MAINTENANCE 1:

PAVEMENT MAINTENANCE 1:Part 2: Distress Identification

Idaho Roads Scholar Program

Learning Objectives

Recognize Asphalt Pavement Distresses

Know the Causes of Main Types of Distress

Determine Which Pavements are Good Candidates for Pavement Preservation

What pavement characteristics indicate pavement condition?

Visible performance indicators Functional indicators Structural indicators

Non-Visible defects Environmental effects on materials Load-related damage

What techniques are used to assess pavement condition?

Visual distress surveys Roughness surveys Friction surveys Drainage evaluation Shoulder surveys Deflection testing

Progression of Pavement Deterioration

Pavement Distress Categories Load

Example: Fatigue Cracking Climate

Example: Weathering/Raveling Other

Construction

Load Related Distresses

Fatigue Cracking Potholes Rutting Edge Cracking Shoving

Fatigue Cracking

Possible Causes Weak base/subgrade Thin pavement / under designed Poor Drainage Overloading

Bottom-up cracking

Fatigue Cracking

Fatigue Cracking

Longitudinal/Transverse Cracking

150 mm

50 mm

Washington State - Top-Down inAsphalt Pavements > 150 mm

M32

M32CORE

TRL

Rutting

In Subgrade/Base Design Problem

In the AC Layer Plastic Flow--Material/Mix Design Consolidation--Compaction Surface Wear

Rutting

Rutting

Rutting in Subgrade/Base

originaloriginalprofileprofile

weak subgrade or underlying layerweak subgrade or underlying layer

asphalt layerasphalt layer

subgradesubgradedeformationdeformation

Rutting in Asphalt Layer

originaloriginalprofileprofile

weak asphalt layerweak asphalt layer

shear planeshear plane

originaloriginalprofileprofile

Wheel path consolidationWheel path consolidation

Improper Improper compactioncompaction

Rutting in Asphalt Layer

Potholes

Severe, uncorrected result of another distress Alligator Cracking Raveling Failed Patches

Thin/Weak Pavement

Potholes

Edge Cracking

Poor lateral support Settlement of underlying material

poor drainage frost heave shrinkage/drying of soil

Aggravated by high traffic levels

Edge Cracking

Shoving

“Washboarding” Occurs at high stress locations

Intersections Steep Grades Ramps

Weak unstable mix Unstable base

Shoving

Climate Related Distresses Block Cracking Joint Reflective Cracking Thermal Cracking Weathering/Raveling

Block Cracking

Divides the pavement into rectangular pieces

1ft x 1ft to 10ft x 10ft Oxidation (Aging) Low AC% Mix Absorptive Aggregates

Block Cracking

Reflective Cracking

Generally over PCC pavements Caused by movement of the

underlying layer Vertically (Load) Horizontally (Thermal)

Reflective Cracking

Longitudinal/Transverse Cracking Transverse cracking is generally

thermally induced Longitudinal Cracking

paving lane joints poor compaction

Longitudinal/Transverse Cracking

Longitudinal/Transverse Cracking

Longitudinal/Transverse Cracking

Weathering/Raveling

Loss of aggregate on the surface Poor Compaction Cold/Wet Weather Construction Dirty Aggregate Low AC% Overheating Mix

Weathering/Raveling

Other Distresses

Bleeding Bumps/Sags Corrugation/

Shoving Depressions Lane/Shoulder

Drop Off

Patching/Utility Cuts

Polished Aggregate

Railroad Crossings

Slippage Cracks

Bleeding

Excessive Asphalt Too much asphalt in mix Too much crack sealant below

overlay Too heavy prime or tack coat?

Low air voids

Bleeding

Bleeding

Slippage Cracks

Caused by a shear plane in the pavement structure Too little tack Too much tack

Slippage Cracks

Primary HMA DeteriorationInitial Mechanisms of Deterioration

Asphalt Asphalt HardeningHardening

Various Various ChangesChanges

Environment /Environment /AgingAging

Material /Material /MixMix

Load / Load / TrafficTraffic

Plastic Plastic DeformationDeformation

Surface wearSurface wear

Primary HMA DeteriorationLoad-Related Distresses

Load

PlasticPlasticDeformationDeformation

RuttingRuttingRuttingRutting

Fatigue CrackingFatigue CrackingFatigue CrackingFatigue Cracking

Primary HMA DeteriorationTraffic-Related Distresses

Traffic

Surface Surface WearWear

Friction LossFriction Loss

PolishingPolishingPolishingPolishing

Primary HMA DeteriorationEnvironment/Aging-Related Distresses

Environment/ Aging

Asphalt Asphalt HardeningHardening

Block CrackingBlock CrackingBlock CrackingBlock Cracking

Raveling/WeatheringRaveling/WeatheringRaveling/WeatheringRaveling/Weathering

Primary HMA DeteriorationMaterial/Mix-Related Distresses

Material Problems

Bleeding/FlushingBleeding/FlushingBleeding/FlushingBleeding/Flushing

Friction LossFriction Loss

Secondary HMA DeteriorationInfluence of Moisture Infiltration

Cracks +

MoistureInfiltration

Deteriorated CracksDeteriorated CracksDeteriorated CracksDeteriorated Cracks

Breakdown of Breakdown of Existing CracksExisting Cracks

Secondary HMA DeteriorationInfluence of Moisture Infiltration

PotholesPotholesPotholesPotholesCracks Cracks ++

MoistureMoistureInfiltrationInfiltration

Subgrade Subgrade SofteningSoftening

Loss of Fines (Pumping)Loss of Fines (Pumping)Loss of Fines (Pumping)Loss of Fines (Pumping)

Lane-to-Shoulder Drop-offLane-to-Shoulder Drop-offLane-to-Shoulder Drop-offLane-to-Shoulder Drop-off

Edge CrackingEdge CrackingEdge CrackingEdge Cracking

Preservation Candidates

Preservation treatments must be applied when: Pavements are in good

condition Corrective actions

required on only a small area of the total pavement

Preservation Candidates

Pavements are not candidates for preservation: Pavements in poor

condition Substantial repairs

required Structural deficiencies

Time or Traffic

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Preventive Preservation Candidates

These Pavements are not Preservation Candidates

Critical PCI

Preservation Candidates

Review Recognize Asphalt Pavement

Distresses Know the Causes of Main Types of

Distress Determine Which Pavements are Good

Candidates for Pavement Preservation

Questions?

Distress

Identification