SlideShare una empresa de Scribd logo
1 de 34
Descargar para leer sin conexión
A Simple Micromechanics-based
Approach for Evaluating the Rutting
  Potential of Asphalt Pavements




           Prof. Björn Birgisson
   The Royal Institute of Technology (KTH)

            Transportforum 2009
Problem Statement
• A test that reflects mixture rutting potential is
  required for:
  – Mixture optimization
  – Mixture design
  – Pass/Fail criteria
Instability Rutting
• It would be nice to use a Superpave
  Gyratory Compactor to Evaluate the Rutting
  Potential of Mixtures
  – It’s readily available
  – It’s simple
  – It’s measures mixture parameters over a range
    of volumetric conditions
Back to Basics
• Question:
  – What are the key elements that are required to
    assess mixture rutting performance using a
    gyratory compaction approach?
• Answer:
  – We need to induce conditions that are most
    relevant to the mechanism of instability rutting
    and measure the relevant response under these
    conditions
Field Observations
  • Rutting instability is associated with plastic
    flow and formation of shear planes



                                               Shear Planes
Tire Contact Studies and Analyses
• Based on previous tire contact studies and associated finite
  element analyses – plot shear stresses and their directions:




• High shear stress in the presence of low confinement and
  even tension appears to be controlling – Defines condition
  of Impending Instability
Focus on Key Mechanism
• Need to induce conditions associated with
  Impending Instability in mixtures and measure the
  relevant response under these conditions

• Using the gyratory compactor:
  – Cannot induce tension or low confinement
  – Can induce high shear stresses by changing gyration
    angle
  – Can create the aggregate structural rearrangement that
    appears associated with impending instability
New Approach
• Create the aggregate structural
  rearrangement that appears associated with
  impending instability
  – Compact mixture to 7 percent air voids at a
    gyratory angle of 1.25 degrees
  – Induce rearrangement of aggregate structure
    using a high shear angle (2.5 degrees)
  – Monitor gyratory shear strength and vertical
    strain
Observed Response
 • At condition of Impending Instability, gyratory shear
   strength peaks, followed by a rearrangement of aggregate
   structure
                                                  1000



                Gyratory Shear Strength (kPa) .
                                                   900
                                                   800
                                                   700
                                                   600
                                                   500
                                                   400       1.25 o     2.5 o
                                                   300
                                                   200
                                                   100
                                                     0
                                                         0       20      40      60       80      100      120   140
                                                                      Number of Gyratory Revolutions (N)


 • Gyratory shear strength may or may not increase after
   rearrangement of aggregate structure
Three Possible Basic Characteristics of Gyratory
Shear Strength Curves at Impending Instability




                      Vertical Strain
Definition of “Failure Strain”




 • Failure strain - the strain at point of local minimum gyratory
   shear strength after increase in gyratory angle
Proposed Framework for the
Evaluation of Rut Resistance
Evaluation of Proposed Framework
• Use a total of 31 Mixtures
   – 10 oolitic limestone mixtures of different gradations
   – 6 Georgia granite mixtures of different gradations
   – 8 mixtures from a previous study on the effect of fine aggregate
     angularity
   – 5 Superpave field mixtures
   – 2 HVS mixtures
   – PG 67-22 used for all mixtures except for an SBS modified HVS
     mixture (PG 76-22)
• Asphalt Pavement Analyzer (APA) measurements obtained
  for all mixtures (at 7 percent Air Voids)
Evaluation of Proposed Framework
                               40
                                                                     Observed APA cracking
                               35                                    APA Rutting > 7.0mm
  Gyratory Shear Slope (kPa)



                                                                     APA Rutting < 7.0mm
                               30

                               25

                               20

                               15

                               10

                               5

                               0
                                    1   1.2   1.4      1.6     1.8       2       2.2         2.4

                                                    Failure Strain (%)
Statistical Evaluation of Results
• A stepwise discriminant function analysis was performed
  using gyratory shear slope and failure strain as predictor
  variables to test the validity of the categories proposed

   – Category 1 – optimal mixtures (shear slope > 15 kPa and failure
                  strain between 1.4 and 2.0 %)
   – Category 2 – Brittle mixes (failure strain < 1.4 %)
   – Category 3 – Mixtures with low shear slope (< 15 kPa)
   – Category 4 – Plastic mixtures (failure strain > 2.0 %)

• The results showed
   – The failure strain was more important than the gyratory shear slope
     in determining the category of each mixture
   – The proposed categories were statistically significant
Field Mixtures Only
                                40
                                                      Observed Field Instability Rutting
                                35
                                                      No Field Instability Rutting
   Gyratory Shear Slope (kPa)



                                30

                                25

                                20

                                15

                                10

                                 5

                                 0
                                     1   1.2   1.4      1.6       1.8       2        2.2   2.4

                                                     Failure Strain (%)
Effects of SBS Modification
                               35
                                                               Unmodified Mixture
                               30                              SBS Modified Mixture
  Gyratory Shear Slope (kPa)




                               25

                               20

                               15

                               10

                                5

                                0
                                    1   1.2   1.4      1.6     1.8       2        2.2   2.4
                                                    Failure Strain (%)
EXPLANATION?
      A Conceptual Model for Mixtures
• Large enough aggregates should engage dominantly in the structure
   (>1.18mm or bigger sieve size) to perform well in terms of cracking
   and rutting
• Either single size or range of particle sizes could form the dominant
   aggregate structure and result in good performance
• Sufficient volume between the dominant aggregate size particles
   would be required for asphalt mastic, and air voids
• Stiffness of this volume should be optimal to prevent excessive
   creep strain rate
Rutting Instability

• Excessive creep strain rate (rutting
  instabiilty) results when:
  – Excessively fine particles are the dominant
    part of the aggregate structure.
  – Inadequate interlock of dominant aggregate
    size range, even when the dominant range is
    composed of coarser particles.
Dominant Aggregate Size Range
                   (DASR)
• Interactive range of particle sizes that forms the primary
  structural network of aggregates. (either one size or a
  range of sizes)
• DASR must be composed of coarse enough particles and
  its porosity must be low enough for a mixture to
  effectively resist deformation and cracking.
• Particles smaller than this range fill the gaps between
  the DASR particles, along with the binder (Interstitial
  Volume) and provide support to the DASR particle
  network.
Dominant Aggregate Size Range
              (DASR)
• Particles larger than those within the DASR
  essentially float in the DASR matrix.
• Particle size retained on 1.18mm sieve size were
  considered as big enough to provide sufficient
  interlock to help resist stress that induces rutting
  and cracking.
Interstitial Volume (IV) &
              Interstitial Components (IC)
 •   The volume of material (AC, AV and aggregates) that exists within the interstices
     of the DASR.
 •   IV serves to hold together the DASR
 •   IC are the components of IV.
 •   The characteristics of IV and the properties of the IC
      – durability and fracture resistance

          Dominant
          Aggregate

            IC, IV




(a) SMA               (b) Coarse dense        (c) Fine dense
Interstitial Volume (IV) &
      Interstitial Components (IC)
• Properties of the IC affect mixture
 performance:
  – Excessively low stiffness and/ or excessively
    high volume may result in high creep rate
  – Excessively high stiffness and/or insufficient
    volume may result in a brittle mixture
DASR Porosity

• For granular materials, 45-50% maximum
  porosity required for stone-on-stone contact
• Stone-on-Stone contact is critical for adequate
  resistance to deformation.
• 50% was selected as a reasonable starting point
  for evaluation.
Spacing Analysis
              4                                                                                                                                           0.25


                                                                                                                                                          0.20
              3
Spacing, cm




                                                                                                                                                          0.15




                                                                                                                                                  Slope
              2                                                                                                                           Large                                                                           Large
                                                                                                                                          Small                                                                           Small
                                                                                                                                                          0.10

              1
                                                                                                                                                          0.05

              0
                                                                                                                                                          0.00
                  100/0

                          95/5

                                 90/10

                                         85/15

                                                   80/20

                                                           70/30

                                                                   60/40

                                                                           50/50

                                                                                   40/60

                                                                                           30/70

                                                                                                   20/80

                                                                                                           15/85

                                                                                                                   10-90

                                                                                                                           5/95

                                                                                                                                  0/100
                                                                                                                                                                 0   10   20   30   40    50   60    70   80   90   100

                                                 Large/Small Particle Proportion                                                                                                % passing for sections



                                     • An approach was developed to determine the spacing between
                                       specified particle sizes on the Interstitial Surface (IS).
                                     • Spacing slope increase steeply when % passing of any particle
                                       size increases 70% in a binary mixture.
                                     • Spacing should be 30-70% for any two contiguous size
                                       particles to interact and behave as a unit.
APLICATION TO ANALYSIS
   OF FIELD PROJECTS

12 Superpave Projects were divided into
three groups based on their gradations
characteristics
Well Performing Group 1: ηDASR < 50%
This included field gradation of projects 3, 4, 5, 7 and plant mix
   gradations of projects 8 and 11

• The DASR porosity was less than 50% along the section.

• Projects 3, 4, 5, and 7 resulted with little or no rutting in the field.

• Project 8 performed very well in the APA and Servopac.

• Project 11 performed well in the APA, Servopac results indicated

   potentially marginal performance.
Poorly Performing Group 2:
                  ηDASR > 50%
This included field gradation of projects 6 and 8, and plant mix
   gradation of projects 9 and 12

• The DASR porosity was greater than 50% along the section.

• Projects 6 and 8 exhibited relatively high rates of rutting in the field.

• Projects 9 and 12 exhibited relatively poor rutting performance in
   the APA and Servopac tests.
Servopac Test Results
                                                              Superpave Servopac Results
                            40
                                     Brittle Mixtures                Optim al Mixtures          Plastic MIxtures
                            35                                                                                           P9 L15A
Gyratory Shear Slope, kPa




                            30
                                                                 DASR Porosity = 50 %                                    P9 L25A
                            25

                            20                                                                                           P9 L15B


                            15
                                                                                                                         P12 L15A

                            10
                                                                    Low Shear Resistance
                                                                                                                         P12 L15B
                            5

                            0
                                 1          1.2         1.4          1.6           1.8      2         2.2          2.4

                                                               Vertical Failure Strain, %
Group 3: Marginal Interaction
This included field gradation of projects 1 and 2 and plant mix
   gradations of project 10

• Marginal interaction @ 4.75-2.36 resulted in variable DASR porosity

   along the section.

• Projects 1 and 2 resulted with relatively high rates of rutting in the

   field and the Servopac.

• Projects 10 exhibited relatively poor rutting performance in the APA
   and Servopac tests.
Conclusions
• For evaluating mixture rutting resistance, we need to induce
  conditions associated with Impending Instability in mixtures
  and measure the relevant response under these conditions

• Using the gyratory compactor, we can create the aggregate
  structural rearrangement that appears associated with
  impending instability

• This can be achieved by inducing high shear stresses by
  increasing the gyratory angle to 2.5 degrees and monitoring
  the gyratory shear strength and vertical strain
Conclusions
• The “failure strain” under the condition of impending
  instability along with gyratory shear slope provide the basis
  for a framework for evaluating the rutting resistance of
  mixtures using the gyratory compactor

• The proposed framework was evaluated and tested using 31
  mixtures of different aggregate structure and aggregate
  properties – Appears to work

• The new framework has the potential for providing an index
  of the rutting potential of mixtures during mix design and
  optimization as well as for QC pass/fail purposes
Conclusions
• A simple micromechanics-based aggregate gradation
  framework appears to explain the observed rutting behavior
  in the field, APA, and the Servopac!
Questions ?

Más contenido relacionado

Similar a Session 30 Björn Birgisson

Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...MarcPortner
 
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...Brian_b
 
Case Study, Evaluating The Long Term Performance Of Composite Wear Rings In C...
Case Study, Evaluating The Long Term Performance Of Composite Wear Rings In C...Case Study, Evaluating The Long Term Performance Of Composite Wear Rings In C...
Case Study, Evaluating The Long Term Performance Of Composite Wear Rings In C...robertaronen
 
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...davidvittes
 
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In C...
 Case Study Evaluating The Long Term Performance Of Composite Wear Rings In C... Case Study Evaluating The Long Term Performance Of Composite Wear Rings In C...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In C...Georage-Gates
 
Formability study of layered material based on numerical analysis
Formability study of layered material based on numerical analysisFormability study of layered material based on numerical analysis
Formability study of layered material based on numerical analysisvikrammistry
 
04-Superpave Binder Testing ( Highway and Airport Engineering Dr. Sherif El-B...
04-Superpave Binder Testing ( Highway and Airport Engineering Dr. Sherif El-B...04-Superpave Binder Testing ( Highway and Airport Engineering Dr. Sherif El-B...
04-Superpave Binder Testing ( Highway and Airport Engineering Dr. Sherif El-B...Hossam Shafiq I
 
Mutooroo Magnetite Project Update October 2012
Mutooroo Magnetite Project Update October 2012Mutooroo Magnetite Project Update October 2012
Mutooroo Magnetite Project Update October 2012Minotaur Exploration
 
Lecture 7 bolted connections-students.pdf
Lecture 7 bolted connections-students.pdfLecture 7 bolted connections-students.pdf
Lecture 7 bolted connections-students.pdfTalhaNadeem43
 
Asphalt Binders Used in Mongolia in the view of Superpave Specification,jul...
Asphalt Binders Used  in Mongolia in the view of  Superpave Specification,jul...Asphalt Binders Used  in Mongolia in the view of  Superpave Specification,jul...
Asphalt Binders Used in Mongolia in the view of Superpave Specification,jul...Bayar Tsend
 
Non linear static analysis aist petti_marino
Non linear static analysis aist petti_marinoNon linear static analysis aist petti_marino
Non linear static analysis aist petti_marinoSoft.lab Srl
 
The effects of minimum and conventional tillage systems on maize grain yield ...
The effects of minimum and conventional tillage systems on maize grain yield ...The effects of minimum and conventional tillage systems on maize grain yield ...
The effects of minimum and conventional tillage systems on maize grain yield ...Joanna Hicks
 
IRJET-Surface Roughness Modeling of Titanium Alloy Grinding
IRJET-Surface Roughness Modeling of Titanium Alloy GrindingIRJET-Surface Roughness Modeling of Titanium Alloy Grinding
IRJET-Surface Roughness Modeling of Titanium Alloy GrindingIRJET Journal
 
Geotextile Degredation Case History - 30 yrs of Performance
Geotextile Degredation Case History - 30 yrs of PerformanceGeotextile Degredation Case History - 30 yrs of Performance
Geotextile Degredation Case History - 30 yrs of Performancebhaladog
 
2016 aci apr18_wollastonite_v3
2016 aci apr18_wollastonite_v32016 aci apr18_wollastonite_v3
2016 aci apr18_wollastonite_v3AsuSSEBENA
 
1223989 static pushover analysis
1223989 static pushover analysis1223989 static pushover analysis
1223989 static pushover analysismansoor_yakhchalian
 

Similar a Session 30 Björn Birgisson (20)

Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
 
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
 
Case Study, Evaluating The Long Term Performance Of Composite Wear Rings In C...
Case Study, Evaluating The Long Term Performance Of Composite Wear Rings In C...Case Study, Evaluating The Long Term Performance Of Composite Wear Rings In C...
Case Study, Evaluating The Long Term Performance Of Composite Wear Rings In C...
 
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In Ce...
 
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In C...
 Case Study Evaluating The Long Term Performance Of Composite Wear Rings In C... Case Study Evaluating The Long Term Performance Of Composite Wear Rings In C...
Case Study Evaluating The Long Term Performance Of Composite Wear Rings In C...
 
Formability study of layered material based on numerical analysis
Formability study of layered material based on numerical analysisFormability study of layered material based on numerical analysis
Formability study of layered material based on numerical analysis
 
04-Superpave Binder Testing ( Highway and Airport Engineering Dr. Sherif El-B...
04-Superpave Binder Testing ( Highway and Airport Engineering Dr. Sherif El-B...04-Superpave Binder Testing ( Highway and Airport Engineering Dr. Sherif El-B...
04-Superpave Binder Testing ( Highway and Airport Engineering Dr. Sherif El-B...
 
Mutooroo Magnetite Project Update October 2012
Mutooroo Magnetite Project Update October 2012Mutooroo Magnetite Project Update October 2012
Mutooroo Magnetite Project Update October 2012
 
Lecture 7 bolted connections-students.pdf
Lecture 7 bolted connections-students.pdfLecture 7 bolted connections-students.pdf
Lecture 7 bolted connections-students.pdf
 
Asphalt Binders Used in Mongolia in the view of Superpave Specification,jul...
Asphalt Binders Used  in Mongolia in the view of  Superpave Specification,jul...Asphalt Binders Used  in Mongolia in the view of  Superpave Specification,jul...
Asphalt Binders Used in Mongolia in the view of Superpave Specification,jul...
 
Packing Characteristics_old
Packing Characteristics_oldPacking Characteristics_old
Packing Characteristics_old
 
Non linear static analysis aist petti_marino
Non linear static analysis aist petti_marinoNon linear static analysis aist petti_marino
Non linear static analysis aist petti_marino
 
Beam column connections
Beam column connectionsBeam column connections
Beam column connections
 
The effects of minimum and conventional tillage systems on maize grain yield ...
The effects of minimum and conventional tillage systems on maize grain yield ...The effects of minimum and conventional tillage systems on maize grain yield ...
The effects of minimum and conventional tillage systems on maize grain yield ...
 
IRJET-Surface Roughness Modeling of Titanium Alloy Grinding
IRJET-Surface Roughness Modeling of Titanium Alloy GrindingIRJET-Surface Roughness Modeling of Titanium Alloy Grinding
IRJET-Surface Roughness Modeling of Titanium Alloy Grinding
 
Steel Jacketed Rc Column
Steel Jacketed Rc ColumnSteel Jacketed Rc Column
Steel Jacketed Rc Column
 
SRE Welding machine catalog
SRE Welding machine catalogSRE Welding machine catalog
SRE Welding machine catalog
 
Geotextile Degredation Case History - 30 yrs of Performance
Geotextile Degredation Case History - 30 yrs of PerformanceGeotextile Degredation Case History - 30 yrs of Performance
Geotextile Degredation Case History - 30 yrs of Performance
 
2016 aci apr18_wollastonite_v3
2016 aci apr18_wollastonite_v32016 aci apr18_wollastonite_v3
2016 aci apr18_wollastonite_v3
 
1223989 static pushover analysis
1223989 static pushover analysis1223989 static pushover analysis
1223989 static pushover analysis
 

Más de Transportforum (VTI)

Abstract session 64 Per Olof Bylund
Abstract session 64 Per Olof BylundAbstract session 64 Per Olof Bylund
Abstract session 64 Per Olof BylundTransportforum (VTI)
 

Más de Transportforum (VTI) (20)

Opening session José Viegas
Opening session José ViegasOpening session José Viegas
Opening session José Viegas
 
Session 26 2010 johan granlund
Session 26 2010 johan granlundSession 26 2010 johan granlund
Session 26 2010 johan granlund
 
Session 37 Bo Olofsson
Session 37 Bo OlofssonSession 37 Bo Olofsson
Session 37 Bo Olofsson
 
Session 28 Irene Isaksson-Hellman
Session 28 Irene Isaksson-HellmanSession 28 Irene Isaksson-Hellman
Session 28 Irene Isaksson-Hellman
 
Session 40 simon gripner
Session 40 simon gripnerSession 40 simon gripner
Session 40 simon gripner
 
Abstract session 64 Per Olof Bylund
Abstract session 64 Per Olof BylundAbstract session 64 Per Olof Bylund
Abstract session 64 Per Olof Bylund
 
Session 64 Per Olof Bylund
Session 64 Per Olof BylundSession 64 Per Olof Bylund
Session 64 Per Olof Bylund
 
Session 7 Leif Blomqvist
Session 7 Leif BlomqvistSession 7 Leif Blomqvist
Session 7 Leif Blomqvist
 
Session 7 Leif Blomqvist.ppt
Session 7 Leif Blomqvist.pptSession 7 Leif Blomqvist.ppt
Session 7 Leif Blomqvist.ppt
 
Session 28 Per Tyllgren
Session 28 Per TyllgrenSession 28 Per Tyllgren
Session 28 Per Tyllgren
 
Session 69 Tor Skoglund
Session 69 Tor SkoglundSession 69 Tor Skoglund
Session 69 Tor Skoglund
 
Session 69 Peter von Heidenstam
Session 69 Peter von HeidenstamSession 69 Peter von Heidenstam
Session 69 Peter von Heidenstam
 
Session 69 Marie-Louise Lundgren
Session 69 Marie-Louise LundgrenSession 69 Marie-Louise Lundgren
Session 69 Marie-Louise Lundgren
 
Session 69 Isak Jarlebring
Session 69 Isak JarlebringSession 69 Isak Jarlebring
Session 69 Isak Jarlebring
 
Session 69 Christian Udin
Session 69 Christian UdinSession 69 Christian Udin
Session 69 Christian Udin
 
Session 69 Marika Jenstav
Session 69 Marika JenstavSession 69 Marika Jenstav
Session 69 Marika Jenstav
 
Session 69 Jana Sochor
Session 69 Jana SochorSession 69 Jana Sochor
Session 69 Jana Sochor
 
Session 69 Göran Erskérs
Session 69 Göran ErskérsSession 69 Göran Erskérs
Session 69 Göran Erskérs
 
Session 69 Cees de Wijs
Session 69 Cees de WijsSession 69 Cees de Wijs
Session 69 Cees de Wijs
 
Session 69 Björn Dramsvik
Session 69 Björn DramsvikSession 69 Björn Dramsvik
Session 69 Björn Dramsvik
 

Último

IaC & GitOps in a Nutshell - a FridayInANuthshell Episode.pdf
IaC & GitOps in a Nutshell - a FridayInANuthshell Episode.pdfIaC & GitOps in a Nutshell - a FridayInANuthshell Episode.pdf
IaC & GitOps in a Nutshell - a FridayInANuthshell Episode.pdfDaniel Santiago Silva Capera
 
Cybersecurity Workshop #1.pptx
Cybersecurity Workshop #1.pptxCybersecurity Workshop #1.pptx
Cybersecurity Workshop #1.pptxGDSC PJATK
 
Comparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and IstioComparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and IstioChristian Posta
 
Nanopower In Semiconductor Industry.pdf
Nanopower  In Semiconductor Industry.pdfNanopower  In Semiconductor Industry.pdf
Nanopower In Semiconductor Industry.pdfPedro Manuel
 
activity_diagram_combine_v4_20190827.pdfactivity_diagram_combine_v4_20190827.pdf
activity_diagram_combine_v4_20190827.pdfactivity_diagram_combine_v4_20190827.pdfactivity_diagram_combine_v4_20190827.pdfactivity_diagram_combine_v4_20190827.pdf
activity_diagram_combine_v4_20190827.pdfactivity_diagram_combine_v4_20190827.pdfJamie (Taka) Wang
 
Salesforce Miami User Group Event - 1st Quarter 2024
Salesforce Miami User Group Event - 1st Quarter 2024Salesforce Miami User Group Event - 1st Quarter 2024
Salesforce Miami User Group Event - 1st Quarter 2024SkyPlanner
 
UiPath Studio Web workshop series - Day 7
UiPath Studio Web workshop series - Day 7UiPath Studio Web workshop series - Day 7
UiPath Studio Web workshop series - Day 7DianaGray10
 
Crea il tuo assistente AI con lo Stregatto (open source python framework)
Crea il tuo assistente AI con lo Stregatto (open source python framework)Crea il tuo assistente AI con lo Stregatto (open source python framework)
Crea il tuo assistente AI con lo Stregatto (open source python framework)Commit University
 
Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™Adtran
 
Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )Brian Pichman
 
Bird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystemBird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystemAsko Soukka
 
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPAAnypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPAshyamraj55
 
COMPUTER 10 Lesson 8 - Building a Website
COMPUTER 10 Lesson 8 - Building a WebsiteCOMPUTER 10 Lesson 8 - Building a Website
COMPUTER 10 Lesson 8 - Building a Websitedgelyza
 
UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdf
UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdfUiPath Solutions Management Preview - Northern CA Chapter - March 22.pdf
UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdfDianaGray10
 
Artificial Intelligence & SEO Trends for 2024
Artificial Intelligence & SEO Trends for 2024Artificial Intelligence & SEO Trends for 2024
Artificial Intelligence & SEO Trends for 2024D Cloud Solutions
 
COMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online CollaborationCOMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online Collaborationbruanjhuli
 
NIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopNIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopBachir Benyammi
 
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...UbiTrack UK
 

Último (20)

IaC & GitOps in a Nutshell - a FridayInANuthshell Episode.pdf
IaC & GitOps in a Nutshell - a FridayInANuthshell Episode.pdfIaC & GitOps in a Nutshell - a FridayInANuthshell Episode.pdf
IaC & GitOps in a Nutshell - a FridayInANuthshell Episode.pdf
 
201610817 - edge part1
201610817 - edge part1201610817 - edge part1
201610817 - edge part1
 
Cybersecurity Workshop #1.pptx
Cybersecurity Workshop #1.pptxCybersecurity Workshop #1.pptx
Cybersecurity Workshop #1.pptx
 
Comparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and IstioComparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and Istio
 
Nanopower In Semiconductor Industry.pdf
Nanopower  In Semiconductor Industry.pdfNanopower  In Semiconductor Industry.pdf
Nanopower In Semiconductor Industry.pdf
 
activity_diagram_combine_v4_20190827.pdfactivity_diagram_combine_v4_20190827.pdf
activity_diagram_combine_v4_20190827.pdfactivity_diagram_combine_v4_20190827.pdfactivity_diagram_combine_v4_20190827.pdfactivity_diagram_combine_v4_20190827.pdf
activity_diagram_combine_v4_20190827.pdfactivity_diagram_combine_v4_20190827.pdf
 
Salesforce Miami User Group Event - 1st Quarter 2024
Salesforce Miami User Group Event - 1st Quarter 2024Salesforce Miami User Group Event - 1st Quarter 2024
Salesforce Miami User Group Event - 1st Quarter 2024
 
UiPath Studio Web workshop series - Day 7
UiPath Studio Web workshop series - Day 7UiPath Studio Web workshop series - Day 7
UiPath Studio Web workshop series - Day 7
 
Crea il tuo assistente AI con lo Stregatto (open source python framework)
Crea il tuo assistente AI con lo Stregatto (open source python framework)Crea il tuo assistente AI con lo Stregatto (open source python framework)
Crea il tuo assistente AI con lo Stregatto (open source python framework)
 
Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™
 
Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )
 
Bird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystemBird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystem
 
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPAAnypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPA
 
COMPUTER 10 Lesson 8 - Building a Website
COMPUTER 10 Lesson 8 - Building a WebsiteCOMPUTER 10 Lesson 8 - Building a Website
COMPUTER 10 Lesson 8 - Building a Website
 
20230104 - machine vision
20230104 - machine vision20230104 - machine vision
20230104 - machine vision
 
UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdf
UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdfUiPath Solutions Management Preview - Northern CA Chapter - March 22.pdf
UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdf
 
Artificial Intelligence & SEO Trends for 2024
Artificial Intelligence & SEO Trends for 2024Artificial Intelligence & SEO Trends for 2024
Artificial Intelligence & SEO Trends for 2024
 
COMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online CollaborationCOMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online Collaboration
 
NIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopNIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 Workshop
 
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
 

Session 30 Björn Birgisson

  • 1. A Simple Micromechanics-based Approach for Evaluating the Rutting Potential of Asphalt Pavements Prof. Björn Birgisson The Royal Institute of Technology (KTH) Transportforum 2009
  • 2. Problem Statement • A test that reflects mixture rutting potential is required for: – Mixture optimization – Mixture design – Pass/Fail criteria
  • 3. Instability Rutting • It would be nice to use a Superpave Gyratory Compactor to Evaluate the Rutting Potential of Mixtures – It’s readily available – It’s simple – It’s measures mixture parameters over a range of volumetric conditions
  • 4. Back to Basics • Question: – What are the key elements that are required to assess mixture rutting performance using a gyratory compaction approach? • Answer: – We need to induce conditions that are most relevant to the mechanism of instability rutting and measure the relevant response under these conditions
  • 5. Field Observations • Rutting instability is associated with plastic flow and formation of shear planes Shear Planes
  • 6. Tire Contact Studies and Analyses • Based on previous tire contact studies and associated finite element analyses – plot shear stresses and their directions: • High shear stress in the presence of low confinement and even tension appears to be controlling – Defines condition of Impending Instability
  • 7. Focus on Key Mechanism • Need to induce conditions associated with Impending Instability in mixtures and measure the relevant response under these conditions • Using the gyratory compactor: – Cannot induce tension or low confinement – Can induce high shear stresses by changing gyration angle – Can create the aggregate structural rearrangement that appears associated with impending instability
  • 8. New Approach • Create the aggregate structural rearrangement that appears associated with impending instability – Compact mixture to 7 percent air voids at a gyratory angle of 1.25 degrees – Induce rearrangement of aggregate structure using a high shear angle (2.5 degrees) – Monitor gyratory shear strength and vertical strain
  • 9. Observed Response • At condition of Impending Instability, gyratory shear strength peaks, followed by a rearrangement of aggregate structure 1000 Gyratory Shear Strength (kPa) . 900 800 700 600 500 400 1.25 o 2.5 o 300 200 100 0 0 20 40 60 80 100 120 140 Number of Gyratory Revolutions (N) • Gyratory shear strength may or may not increase after rearrangement of aggregate structure
  • 10. Three Possible Basic Characteristics of Gyratory Shear Strength Curves at Impending Instability Vertical Strain
  • 11. Definition of “Failure Strain” • Failure strain - the strain at point of local minimum gyratory shear strength after increase in gyratory angle
  • 12. Proposed Framework for the Evaluation of Rut Resistance
  • 13. Evaluation of Proposed Framework • Use a total of 31 Mixtures – 10 oolitic limestone mixtures of different gradations – 6 Georgia granite mixtures of different gradations – 8 mixtures from a previous study on the effect of fine aggregate angularity – 5 Superpave field mixtures – 2 HVS mixtures – PG 67-22 used for all mixtures except for an SBS modified HVS mixture (PG 76-22) • Asphalt Pavement Analyzer (APA) measurements obtained for all mixtures (at 7 percent Air Voids)
  • 14. Evaluation of Proposed Framework 40 Observed APA cracking 35 APA Rutting > 7.0mm Gyratory Shear Slope (kPa) APA Rutting < 7.0mm 30 25 20 15 10 5 0 1 1.2 1.4 1.6 1.8 2 2.2 2.4 Failure Strain (%)
  • 15. Statistical Evaluation of Results • A stepwise discriminant function analysis was performed using gyratory shear slope and failure strain as predictor variables to test the validity of the categories proposed – Category 1 – optimal mixtures (shear slope > 15 kPa and failure strain between 1.4 and 2.0 %) – Category 2 – Brittle mixes (failure strain < 1.4 %) – Category 3 – Mixtures with low shear slope (< 15 kPa) – Category 4 – Plastic mixtures (failure strain > 2.0 %) • The results showed – The failure strain was more important than the gyratory shear slope in determining the category of each mixture – The proposed categories were statistically significant
  • 16. Field Mixtures Only 40 Observed Field Instability Rutting 35 No Field Instability Rutting Gyratory Shear Slope (kPa) 30 25 20 15 10 5 0 1 1.2 1.4 1.6 1.8 2 2.2 2.4 Failure Strain (%)
  • 17. Effects of SBS Modification 35 Unmodified Mixture 30 SBS Modified Mixture Gyratory Shear Slope (kPa) 25 20 15 10 5 0 1 1.2 1.4 1.6 1.8 2 2.2 2.4 Failure Strain (%)
  • 18. EXPLANATION? A Conceptual Model for Mixtures • Large enough aggregates should engage dominantly in the structure (>1.18mm or bigger sieve size) to perform well in terms of cracking and rutting • Either single size or range of particle sizes could form the dominant aggregate structure and result in good performance • Sufficient volume between the dominant aggregate size particles would be required for asphalt mastic, and air voids • Stiffness of this volume should be optimal to prevent excessive creep strain rate
  • 19. Rutting Instability • Excessive creep strain rate (rutting instabiilty) results when: – Excessively fine particles are the dominant part of the aggregate structure. – Inadequate interlock of dominant aggregate size range, even when the dominant range is composed of coarser particles.
  • 20. Dominant Aggregate Size Range (DASR) • Interactive range of particle sizes that forms the primary structural network of aggregates. (either one size or a range of sizes) • DASR must be composed of coarse enough particles and its porosity must be low enough for a mixture to effectively resist deformation and cracking. • Particles smaller than this range fill the gaps between the DASR particles, along with the binder (Interstitial Volume) and provide support to the DASR particle network.
  • 21. Dominant Aggregate Size Range (DASR) • Particles larger than those within the DASR essentially float in the DASR matrix. • Particle size retained on 1.18mm sieve size were considered as big enough to provide sufficient interlock to help resist stress that induces rutting and cracking.
  • 22. Interstitial Volume (IV) & Interstitial Components (IC) • The volume of material (AC, AV and aggregates) that exists within the interstices of the DASR. • IV serves to hold together the DASR • IC are the components of IV. • The characteristics of IV and the properties of the IC – durability and fracture resistance Dominant Aggregate IC, IV (a) SMA (b) Coarse dense (c) Fine dense
  • 23. Interstitial Volume (IV) & Interstitial Components (IC) • Properties of the IC affect mixture performance: – Excessively low stiffness and/ or excessively high volume may result in high creep rate – Excessively high stiffness and/or insufficient volume may result in a brittle mixture
  • 24. DASR Porosity • For granular materials, 45-50% maximum porosity required for stone-on-stone contact • Stone-on-Stone contact is critical for adequate resistance to deformation. • 50% was selected as a reasonable starting point for evaluation.
  • 25. Spacing Analysis 4 0.25 0.20 3 Spacing, cm 0.15 Slope 2 Large Large Small Small 0.10 1 0.05 0 0.00 100/0 95/5 90/10 85/15 80/20 70/30 60/40 50/50 40/60 30/70 20/80 15/85 10-90 5/95 0/100 0 10 20 30 40 50 60 70 80 90 100 Large/Small Particle Proportion % passing for sections • An approach was developed to determine the spacing between specified particle sizes on the Interstitial Surface (IS). • Spacing slope increase steeply when % passing of any particle size increases 70% in a binary mixture. • Spacing should be 30-70% for any two contiguous size particles to interact and behave as a unit.
  • 26. APLICATION TO ANALYSIS OF FIELD PROJECTS 12 Superpave Projects were divided into three groups based on their gradations characteristics
  • 27. Well Performing Group 1: ηDASR < 50% This included field gradation of projects 3, 4, 5, 7 and plant mix gradations of projects 8 and 11 • The DASR porosity was less than 50% along the section. • Projects 3, 4, 5, and 7 resulted with little or no rutting in the field. • Project 8 performed very well in the APA and Servopac. • Project 11 performed well in the APA, Servopac results indicated potentially marginal performance.
  • 28. Poorly Performing Group 2: ηDASR > 50% This included field gradation of projects 6 and 8, and plant mix gradation of projects 9 and 12 • The DASR porosity was greater than 50% along the section. • Projects 6 and 8 exhibited relatively high rates of rutting in the field. • Projects 9 and 12 exhibited relatively poor rutting performance in the APA and Servopac tests.
  • 29. Servopac Test Results Superpave Servopac Results 40 Brittle Mixtures Optim al Mixtures Plastic MIxtures 35 P9 L15A Gyratory Shear Slope, kPa 30 DASR Porosity = 50 % P9 L25A 25 20 P9 L15B 15 P12 L15A 10 Low Shear Resistance P12 L15B 5 0 1 1.2 1.4 1.6 1.8 2 2.2 2.4 Vertical Failure Strain, %
  • 30. Group 3: Marginal Interaction This included field gradation of projects 1 and 2 and plant mix gradations of project 10 • Marginal interaction @ 4.75-2.36 resulted in variable DASR porosity along the section. • Projects 1 and 2 resulted with relatively high rates of rutting in the field and the Servopac. • Projects 10 exhibited relatively poor rutting performance in the APA and Servopac tests.
  • 31. Conclusions • For evaluating mixture rutting resistance, we need to induce conditions associated with Impending Instability in mixtures and measure the relevant response under these conditions • Using the gyratory compactor, we can create the aggregate structural rearrangement that appears associated with impending instability • This can be achieved by inducing high shear stresses by increasing the gyratory angle to 2.5 degrees and monitoring the gyratory shear strength and vertical strain
  • 32. Conclusions • The “failure strain” under the condition of impending instability along with gyratory shear slope provide the basis for a framework for evaluating the rutting resistance of mixtures using the gyratory compactor • The proposed framework was evaluated and tested using 31 mixtures of different aggregate structure and aggregate properties – Appears to work • The new framework has the potential for providing an index of the rutting potential of mixtures during mix design and optimization as well as for QC pass/fail purposes
  • 33. Conclusions • A simple micromechanics-based aggregate gradation framework appears to explain the observed rutting behavior in the field, APA, and the Servopac!