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Material Characterization

Material Characterization

Purpose:• to understand material behavior• construction control• material properties for design( h= f (material))• pavement evaluationpavement evaluation• establish failure criteria

Types of tests:• Arbitrary: CBR, Stability....• Fundamental: Triaxial, Diametral...• Full Scale: AASHTO road test, ...

Requirement:• establish properties: Test....• Failure criteria: Fatigue, rutting, deformation, serviceability...

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Material Testing

soils and granular materials:soil classificationsubgrade support (plate bearing, k)California bearing ratio (CBR)California bearing ratio (CBR)Static triaxial test (φ, angle of internal friction, C, cohesion and τ, shear)Dynamic triaxial test ( permanent deformation, resilient modulus (Mr) for fine and coarse materials and poisons ratio (μ))

Bituminous materials testing:Marshall testSuperPaveModulus of rupture, MRindirect tensile test, ITS or σTDiametral test, resilient modulus,MrDynamic triaxial, resilient modulus,Mr, poisons ratio (μ)and permanent deformationcomplex dynamic modulus, E*

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subgrade support (plate bearing, k)

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p

k = P / ∆

∆

σ2 = σ1- σ3

Static triaxial test (φ, angle of internal friction, C, cohesion and τ, shear)

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φστ tan+= c

σ3 σ2

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Dynamic triaxial test ( permanent deformation, resilient modulus (Mr) for fine and coarse materials and poisons ratio (μ))

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Mr =(σ1- σ3) /εz = σ2/εz

μ = εr / εz

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Dynamic triaxial test

G l M t i lGranular Materials

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Fine Grained Materials

K1

K2

Modulus of rupture, MR, Es

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indirect tensile test, ITS or σT

σ = 2P / π d t

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σT = 2P/μ D H

dtP

π=σ=

2StressTensileHorizontal

⎥⎦

⎤⎢⎣

⎡πμ+

μ+δ=ε=

)()31(2StrainTensileHorizontal

bad

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Diametral test, resilient modulus,Mr

Diametral test

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Diametral test

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Dynamic triaxial test

εp= I NS

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Diametral test

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Bending Beam Fatigue test

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Fatigue concept

Nf =k1(1/δ)k2

N k3(1/Є)k4Nf =k3(1/Є)k4