Instability Rutting

Instability Rutting - Proposed Failure Mechanism for...

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Proposed Failure Mechanism for Instability Rutting in Asphalt Pavements Reebie Simms
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3-D Tire-Pavement Model Developed a 3-D FEM model of a radial dual truck and typical pavement system Stress states under the tire loading in the middle transverse plane of interest Investigated instability rutting using induced stress states
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Investigation of Slip Planes Using the 3D Tire- Pavement Contact Model examine multiple depths within the AC layer Can we identify a mechanism that causes instability rutting ? Is there a critical depth(s)?
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Yield Ratio Use the concept of yield ratio (YR) to determine the degree of criticality of each stress state Mohr-Coulomb criterion assumes the material will fail or yield if q is equal to q f (in p-q space) or the YR is equal to 1 k-line: q f = a + p tan( )
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Yield Ratio (cont.) C:30 psi ;Ф: 20º YR for multiple depths along middle vertical plane 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 -10 -8 -6 -4 -2 0 2 4 6 8 10 YR Tire Lateral Location (in.) Yield-Ratio 1in 2in 2.8in 4in No sense of direction – direction important in shear flow! No sense of continuity to form slip planes
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Maximum Shear Each element has an equal and opposite max. shear stress Always choose positive max. shear to ensure continuity of the potential slip plane causing the material to flow to the right Action Reaction
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Maximum Shear (cont.) Superimpose max. shear contour with max. shear vectors Both magnitude and direction important 0 2 4 6 8 10 12 -4 -3 -2 -1 0
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Maximum Shear (cont.) Choose potential slip planes Plane No.
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This note was uploaded on 05/26/2011 for the course CGN 6505 taught by Professor Mang during the Spring '11 term at University of Florida.

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Instability Rutting - Proposed Failure Mechanism for...

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