Deterioration of Concrete Roads

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Concrete Roads

• Joint Spalling• Punch outs• Cracking• Faulting• Slab failures• Riding Quality

Models FromUSAChile

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• Absolute (Concrete HDM-4)Predicts the future conditionCONDITION = f(a0, a1, a2)

Limited to conditions model developed forProblems with calibration

• Incremental (Asphalt HDM-4)Predicts the change in condition from the current condition:

Δ CONDITION = f(a0, a1, a2)Can use any start point so much more flexible

Types of Deterministic Models

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Surface types upon which the concrete RD models are based

Surface type Description

JP Jointed Plain concrete pavement - without load transfer dowels

JP Jointed Plain concrete pavement - with load transfer dowels

JR Jointed Reinforced concrete pavement

CR Continuously Reinforced concrete pavement

Concrete Roads Surface Types

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Joint spacing3 - 6 m

AggregateInterlockSlab

Base

Figure 2.1 Jointed plain concrete pavements without dowels

Jointed Plain Concrete Pavement without Dowels

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Joint spacing3 - 6 m

Dowels

Figure 2.2 Jointed plain concrete pavements with dowels

Jointed Plain Concrete Pavement with Dowels

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10 - 20 m

DowelsSlab

Base

Joint spacing

Welded wire fabric (0.1 – 0.2%)

Figure 2.3 Jointed reinforced concrete pavements

Jointed Reinforced Concrete Pavement

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Cracks separationSlab

Base

Reinforcement steel0,6 - 0,8 % of area

Figure 2.4 Continuously reinforced concrete pavements

Continuously Reinforced Concrete Pavement

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Distress modes modelled in HDM-4

No. Distress mode Units of measurement Pavement surface type

1 Cracking Percent of slabs cracked JP

Number per mile JR

2 Faulting inches JP and JR

3 Spalling Percent of spalled joints JP and JR

4 Failures Number per mile CR

5 Serviceability loss Dimensionless JR and CR

6 Roughness Inches per mile (or m/km) JP, JR and CR

Distress Modes

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• The principal data for predicting the deterioration of concrete pavements:

Properties of materialsPercentage of reinforcement steelDrainage conditionsLoad transfer efficiency (across joints, and between slabs and shoulder)Widened outside lanes

Structural Characteristics

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• Transverse cracking occur due to high stress levels in the slabs or defects originating from material fatigue

• The stresses are caused by the combined effect of thermal curling, moisture-induced curling and traffic loading

Cracking

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Transverse Cracking

C DTransv.

Joint

Traffic

A B C D

Distresswidth

Distresswidth

Slab

Shoulder

CLLongitudinal Joint

Transv.Joint

A B

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• Transverse cracking (% of slabs cracked) is modelled as a function of cumulative fatigue damage in the slabs and:

Cumulative ESALsTemperature gradientMaterial propertiesSlab thicknessJoint spacing

Cracking in JP Pavements

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• The number of deteriorated transverse cracks per km is predicted as a function of:

Cumulative ESALsPavement ageSlab thickness and Ec

Percentage of reinforcement steel, PSTEELBase typeClimate/environment (FI, MI)

Cracking in JR Pavements

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Curling

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Curling

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Curling and Traffic Loading

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Curling and Corner Distresses

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• Faulting is caused by the loss of fine material under a slab and the increase in fine material under nearby slabs

• This flow of fine material is called pumping, and is caused by the presence of high levels of free moisture under a slab carrying heavy traffic loading

• The effects of thermal and moisture-induced curling and lack of load transfer between slabs increase pumping

Faulting

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Faulting

Transv.Joint

TrafficSlab

CLLongitudinal Joint

Transv.Joint

A B

A Bfaulting

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• The average transverse joint faulting is predicted as a function of:

Cumulative ESALsSlab thicknessJoint spacing and openingProperties of materialLoad transfer efficiencyClimate/environment (FI, PRECIP, DAYS90)Base typeWidened outside lanes

Faulting

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Agua

p

Carga en Losa de Aproximación

Movimiento Lento del Agua

Faulting

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Carga en Losa de Alejamiento

Movimiento Rápido del Agua

INERCIA

IMPULSIONSUCCION

Depósito de Sólidos Base Erosionada

ESCALONAMIENTO

Faulting

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• Transverse joint spalling is the cracking or breaking of the edge of the slab up to a maximum of 0.6 m from the joint.

• Transverse joint spalling can be caused by:• Presence of incompressible materials• Disintegration of concrete under high traffic

loading• Improper consolidation of the concrete in

the joint• Wrongly designed or built load transfer

system

Spalling

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• Transverse joint spalling is predicted as a function of:

Pavement ageJoint spacingType of sealDowel corrosion protectionBase typeClimate/environment (FI, DAYS90)

Spalling

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Spalling

Shoulder

Traffic

Transv.Joint

Low Sev.:1,8 m

High Sev.:1,5 m

Low Sev.:2 m Moder. Sev.:

2,5 m

A B

C D

A B

Distresswidth

Joint

C D

< 0,6 m

JointCrack

Transv.Joint

Transv.Joint

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Spalling

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• Localised failures include loosening and breaking of reinforcement steel and transverse crack spalling

• These are caused by high tensile stresses induced in the concrete and reinforcement steel by traffic loading and changes in environmental factors

• The number of failures is predicted as a function of:Slab thicknessPercentage of reinforcement steelCumulative ESALsBase type

Failures in CR Pavements

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• This is a subjective user rating of the existing ride quality of a pavement (ranging from 0 extremely poor to 5 extremely good)

• For JR pavements, the change in PSR is calculated as a function of cracking, spalling and faulting

• For CR pavements, the change in PSR is calculated as a function of slab thickness, cumulative ESALs and pavement age

Present Serviceability Index

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• For JP concrete pavements, roughness is calculated as a function of faulting, spalling and cracking

• For JR and CR concrete pavements, roughness is calculated as a function of PSR

Roughness

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IRI• IRIo• Transversal Cracks• Faulting• Spalling

== ff

ESAL

IRI

IRIoIRIo

Roughness on JPCP

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• Modulus of elasticity of concrete, Ec

• Modulus of rupture of concrete, MR28• Thermal coefficient of concrete, α• Drying shrinkage coefficient of concrete, γ• Poisson’s ratio for concrete, μ• Modulus of elasticity of dowel bars, Es

• Modulus of elasticity of bases, Ebase

• Modulus of subgrade reaction, KSTAT

Property of Materials

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Maintenance Works (1)Maintenance works for concrete pavements

Pavement surface typeWorksclass

Works type Works activities

JP JR CR

Routine Routinemaintenance

Vegetation control, line marking, draincleaning, etc.

a a a

Load transfer dowels retrofit a

Tied concrete shoulders retrofit a a

Longitudinal edge drains retrofit a a

Preventivetreatment

Joint sealing a a

Slab replacement a

Full depth repair a a

Partial depth repair aRestoration

Diamond grinding a a

Bonded concrete overlay a a aRehabilitation

Unbonded concrete overlay a a a

Periodic

Reconstruction Pavement reconstruction a a a

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Maintenance Works (2)

Maintenance works applicable to JP concrete carriageway

Works type Works activity / operation ID code Ranking Unit cost

Reconstruction Pavement reconstruction REC 1 per m2

Unbonded concrete overlay UOL 2 per m2

RehabilitationBonded concrete overlay BOL 3 per m2

Slab replacement SLR 4 per m2

Partial depth repair PDR 5 per m (joint length)Restoration

Diamond grinding* DGR 6 per m2

Load transfer dowels retrofit* DWL 7 per m (joint length)

Tied concrete shoulders retrofit* TCS 7 per km

Longitudinal edge drains retrofit* RED 7 per km

Preventivetreatment

Joint sealing* SLJ 7 per m (joint length)

Note:

* Works activity can be applied together with slab replacement or partial depth repair in the sameanalysis year

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Maintenance Works (3)

Maintenance works applicable to JR concrete carriageway

Works type Works activity / operation ID code Ranking Unit cost

Reconstruction Pavement reconstruction REC 1 per m2

Unbonded concrete overlay UOL 2 per m2Rehabilitation

Bonded concrete overlay BOL 3 per m2

Full depth repair FDR 4 per m2

RestorationDiamond grinding* DGR 5 per m2

Tied concrete shoulders retrofit* TCS 6 per km

Longitudinal edge drains retrofit* RED 6 per kmPreventivetreatment

Joint sealing* SLJ 6 per m (joint length)

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HDM Series – Volume 4