139 compaction presentation

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139 compaction presentation

  1. 1. 1Simulation of compaction of asphalt concrete Alieh Alipour Simulation of compaction of asphalt concrete Alieh Alipour Delft University of Technology Section of Pavement Engineering
  2. 2. 2Simulation of compaction of asphalt concrete Alieh Alipour Simulation No-Tension characteristics of aggregates Simulation Compaction of asphalt concrete layer
  3. 3. 3Simulation of compaction of asphalt concrete Alieh Alipour Compaction Reduction of air voids in hot mix asphalt by applying force Desired Density
  4. 4. 4Simulation of compaction of asphalt concrete Alieh Alipour  Increase stability and strength  Decrease moisture damage  Decrease rutting and consolidation by traffic Effect of compaction on pavement performance Low level of compaction high level of compaction
  5. 5. 5Simulation of compaction of asphalt concrete Alieh Alipour Important parameters in compaction  Composition of asphalt mixture  Mixture with high volume of natural sand and soft bitumen  Mixture with high volume of crushed aggregates and stiff bitumen
  6. 6. 6Simulation of compaction of asphalt concrete Alieh Alipour Important parameters affecting compaction  Temperature  Initial mixture temperature  Base temperature  Air temperature  Wind speed  Layer thickness Compactioneffort Mix temperature in ⁰C End of Compaction Favourable Compaction Temperature Start of Compaction 40 60 80 100 120 140 160 180 200
  7. 7. 7Simulation of compaction of asphalt concrete Alieh Alipour Important parameters in compaction  Type and magnitude of applied load  Static compaction  Tandem rollers  Pneumatic tired rollers  Vibratory compaction
  8. 8. 8Simulation of compaction of asphalt concrete Alieh Alipour Level of compaction Void content (%) Density (kg/m3 ) Specific volume (%) volume of voids in mixture 100% volume of total mixture including air aV     3 weight of the material kg volume of the material [m ]   total volume of mixture 100% volume of solid part of the mixture v  
  9. 9. 9Simulation of compaction of asphalt concrete Alieh Alipour Methods of compaction Laboratory compaction method Field compaction method Marshal Superpave
  10. 10. 10Simulation of compaction of asphalt concrete Alieh Alipour Methods of measuring compaction Laboratory compaction method Field compaction method Modelling compaction (FEM)Aggregate properties Bitumen properties Environment information Type of roller Number of passes Suitable mix design
  11. 11. 11Simulation of compaction of asphalt concrete Alieh Alipour Constitutive Model  Phase 1 : Aggregates matrix (Elasto-Plastic)  EffectofPressureontangentmoduli  Effect of void reduction
  12. 12. 12Simulation of compaction of asphalt concrete Alieh Alipour Constitutive Model  Phase 2 : Bitumen (Visco-Elastic) Viscosity Temperature in ⁰C
  13. 13. 13Simulation of compaction of asphalt concrete Alieh Alipour Pressure dependent elasticity p p p p p Bulk Modulus (K) Pressure dependent force Shear Modulus (G) Constant
  14. 14. 14Simulation of compaction of asphalt concrete Alieh Alipour Loading-unloading curve lnv ln( )p Normal consolidation line Swelling line Plastic volume changing Elastic volume changing Nonlinear elastic law Triaxial test device 2p1p
  15. 15. 15Simulation of compaction of asphalt concrete Alieh Alipour 2J 1I Yield surface for aggregates matrix 2 2 2 2 1 2 2 3 3 1 1 ( ) ( ) ( ) 6 J            1 2 3 2 1 Invariants of stress tensor 1 1 2 3 1 ( ) 3 I       Yield surface (growth) 1 1I I 
  16. 16. 16Simulation of compaction of asphalt concrete Alieh Alipour Hardening rule based on experimental data lnv ln( )p 2J 1I Hardening Law Loading- unloading curve Yield surface
  17. 17. 17Simulation of compaction of asphalt concrete Alieh Alipour Results Stress-Strain curve for hydrostatic test P P P
  18. 18. 18Simulation of compaction of asphalt concrete Alieh Alipour Results Equivalent Plastic Strain development for hydrostatic test P P P
  19. 19. 19Simulation of compaction of asphalt concrete Alieh Alipour Conclusions and future plans  Develop a model to simulate no-tension characteristics of unbound aggregates in base and subbase layer  Develop a model to simulate compaction of aggregates (elasto-plasticity)  Consider the effect of viscosity and temperature to simulate compaction of asphalt mixture (elasto-visco-plasticity)  Evaluate the model with experimental data  Develop CST (Compaction Simulation Tool)
  20. 20. 20Simulation of compaction of asphalt concrete Alieh Alipour a.alipour@tudelft.nl

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