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MODELS FOR PERMANENT DEFORMATION FOR BITUMINOUS BOUND MATERIALS IN FLEXIBLE PAVEMENTS Deliverable 11. Survey Models Test Types Required Laboratory Test Data Further Steps Discussion and Questions. SURVEY PRESENTATION:. Survey Models Test Types Required Data Further Steps. SURVEY MODELS.
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MODELS FOR PERMANENT DEFORMATION FOR BITUMINOUS BOUND MATERIALS IN FLEXIBLE PAVEMENTS • Deliverable 11 SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Survey Models Test Types Required Laboratory Test Data Further Steps Discussion and Questions SURVEYPRESENTATION: • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
SURVEY MODELS • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
DSR Tests (Binder) Francken Shear Tests (SST) SHRP Uniaxial Creep Test Erkens Uniaxial Dynamic Test SPDM Triaxial Creep Test DBN Triaxial Dynamic Test Francken, ISTU Uniaxial Tension Test Erkens SUMMARY TEST TYPES • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
REQUIRED LABORATORY TESTS • Survey Models • Test Types • Required Data • Further Steps ... test performed at ISTU–Lab ... SHELL ... TRL SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
FURTHER STEPS Literaturestudy (models) Selection of potential models for validation Deliverable 11 Selection of models for validation Data Lausanne Calibration of selected models Laboratory Test Data Data DART Data Nantes ? • Survey Models • Test Types • Required Data • Further Steps Validation of the selected models Deliverable 28 SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
FURTHER STEPS • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Permanent Deformation Model by Francken/BRRC • Basic principles: • Material model • Based on triaxial dynamic tests • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Francken / Basic principles: • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Francken / Basic principles: • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Francken / Key equations p... plastic deformation 1... amplitude of vertical stress 3... lateral stress Ep... plastic deformation modulus N... number of load repetitions f... load frequency f()... coefficient, dependent on the void content E*... complex elastic modulus • Key equations: • E∞... purely elastic or „glassy“ modulus • R*... reduced modulus • T... temperature • VA... aggregate content [Vol %] • VB... binder content [Vol %] • F*... reduced shear modulus (binder) • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Survey Models Test Types Required Data Further Steps • Francken / Input parameters • Input parameters for the model: • Complex elastic modulus E* • Complex shear modulus G* of the binder • Aggregate content [vol. %] • Binder content [vol. %] Triaxial test DSR and vol. asphalt characteristics SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Rutting Prediction within the SHELL Pavement Design Method (SPDM) • Basic principles: • Rutting prediction model • Multi layer theory (BISAR) • Based on the ratio of the stiffness of the asphaltic mix and its bituminous binder • Uniaxial repeated load tests or RSST-CH for determination of input parameters • SPDM-PC program for the calculation of rut depths • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
SPDM / Key equations • Key equations: • Survey Models • Test Types • Required Data • Further Steps Smix,v Stiffness of the mix Sbit,v Viscous component of the stiffness of the bituminous binder b, q... Parameters, specific for a certain asphaltic mix, determined by creep tests 0... Bitumen viscosity at the average paving temperature Weq... ESALs tw... Wheel loading time (traffic speed) h... Rut depth k... Coefficient k=CmZ0, dynamic factor Cm= 1 by default Z0... Configuration factor 0... Contact stress of the standard wheel av,0...Average stress in the asphalt layer resulting from one standard wheel pass h... Thickness of the asphalt layer SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Survey Models Test Types Required Data Further Steps • SPDM / Input parameters • Input parameters for the model: • Traffic: axle loads, wheels per axle, axles per day and line, contact stress, rate of traffic growth per year, design period, loading time • Climate: MMAT (Mean Monthly Air Temperature in °C) • Material characteristics: penetration of the bitumen at 25°C, softening point of the bitumen, polymer modified bitumens: viscosities at two temperatures, mix composition (Vol.% bitumen, Vol.% aggregate), creep characteristics (parameters q and b) • Structure: total thickness of asphalt layers, thickness of sub-base, Poisson’s ratio of asphalt layers, of the sub-base and of the subgrade, modulus of elasticity of the sub-base and the subgrade SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Survey Models Test Types Required Data Further Steps WT 8-1 WT 8-3 WT 9-1 Permanent shear deformation p RSST load cycles 50 °C @ 70kPa 0.1 5% 0.01 0.001 10 100 1,000 10,000 1 RSST Belastungszyklen Rutting prediction model within the Strategic Highway Research Programme (SHRP) – Level I • Basic principles: • Rutting prediction model • RSST-CH for determination of the input parameters • Traffic and climate assumptions included into model SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
SHRP Level I / Basic principles Select pavement structural section Select trial mix Traffic, Environment Mix not satisfactory From simple shear test(s) at Tc select Nsupply for predetermined allowable rut depth Determine critical temperature Tc Select multiplier M for Ndemand to reflect design reliability and variabilities in Nsupply and Ndemand Convert estimated traffic to Ndemand at Tc Compute M ∙ Ndemand Nsupply < M ∙Ndemand Nsupply M ∙Ndemand Compare Nsupply with Ndemand Mix satisfactory SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
SHRP Level I / Key equations • Key equations: Ndemand... applied traffic demand TCF... temperature conversation factor (to be determined for specific climatic conditions) SF... empirically determined shift factor (traffic wander, construction variability, differences between field and laboratory stress conditions, etc.) Nsupply... estimated load repetitions to a limiting prescribed rut depth M... reliability factor • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
SHRP Level I / Input parameters • Input parameters for the model: • ESALs • Temperature in form of a temperature equivalency factor • Chosen reliability • Nsupply from RSST-CH for allowable rut depth • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
P0 E0 E1 1 ... En n Permanent deformation model within the Strategic Highway Research Programme (SHRP) – Level II • Basic principles: • Based on a rheological model (see figure) • FS-S, volumetric tests (SST) and uniaxial strain test (SST) for the determination of the input parameters • FE analysis Elastoplastic branch Maxwell model • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
SHRP Level II / Basic principles Select pavement structural section Select trial mix Traffic Environment Mix not satisfactory Perform suite of tests to define mix parameters for constitutive relationship Response model Estimate rut depth for Ndemand using FE solution rdcalc rdallow rdcalc rdallow Compare rdcalc with rdallow Mix satisfactory SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
SHRP Level II / Input Parameters • Input parameters for the model: • Traffic and climate data see Level I • Parameters for the rheological model: • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Asphalt Concrete Response model (ACRe) by Erkens / Delft • Basic principles: • Material model • Based on Desai model (figure) • Uniaxial creep tests and uniaxial tension tests for the determination of the input parameters • FE analysis • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
ACRe / Key equations and input parameters • Key equations: I1... first invariant of the stress tensor p... isotropic stress J2... second deviatoric stress invariant J3... third deviatoric stress invariant , , , n, R: model parameter • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Permanent Deformation Prediction Based on a Generalized Maxwell Model • Basic principles: • Rheological Material model Decomposition of the Stress Tensor • Pressure volume partof the material behavior is assumed to be governed by a linear elastic model • Deviatoric parts are assumed to satisfy a viscoelastic model of a Generalized Maxwell Model • Frequency sweep shear tests (FS-S) or dynamic triaxial tests at different frequencies and temperatures • FE analysis • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Stress Tensor Volumetric Part Deviatoric Part Linear elastic model Generalized Maxwell model G1 G2 Gn K0 G0 t1 t2 tn Permanent Deformation Prediction Based on a Generalized Maxwell Model REPRESENTATION & CONSTITUTIVE EQUATIONS Representation Constitutive Equations • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
FS-S - TEST GENERALIZED MAXWELL MODEL d G‘(w) G“(w) G* RELATIONSHIP (Tschoegl, 1988) RESULTS G*(w) d (w) Gn G2 G1 G0 tn t1 t2 Permanent Deformation Prediction Based on a Generalized Maxwell Model MATERIAL MODEL MATERIAL TESTING DATA FITTING PARAMETER elastic: G0, G1, ... Gn viscous: t1, t2, ... tn • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
PERSPECTIVE VIEW OF THE FE - MESH 2,448 mm 1,632 mm 612 mm 408 mm z y x Permanent Deformation Prediction Based on a Generalized Maxwell Model REPRESENTATION OF A PAVEMENT IN A 3D FE - SYSTEM • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04 28
VRSPTA MEASUREMENT FE – LOAD INPUT VERTICAL CONTACT STRESS(FE – LOAD PATTERN) TIRE FOOTPRINT VERTICAL CONTACT STRESS(TRANSPOSED SIM MEASUREMENT) Permanent Deformation Prediction Based on a Generalized Maxwell Model LOAD MODEL Radial Tire - 56kN @ 690 kPa SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Pavement 70 mm 140 mm Permanent Deformation Prediction Based on a Generalized Maxwell Model SIMULATION RESULTS 100.000 Load cycles Normal stresses s22 • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04 30
EP1 EP2 EPN (a) VN+1 EP0 V1 V2 VN E0 EP1 EP2 EPN (b) 1(T) 2(T) N(T) Permanent Deformation Model by Di Benedetto and Neifar (DBN) / ENTPE • Basic principles: • Material model • Based on a generalized Kelvin-Voigt (KV) model • Calibration of the KV model by means of the Huet-Sayegh model and a viscoplastic criterion by Di Benedetto • Triaxial creep tests for the determination of the input parameters • Computer program • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
DBN / Basic principles (b) viscoplastic criterion by Di Benedetto Used for model calibration in case of viscoplastic flow (a) Huet-Sayegh model Used for calibration in the small strain domain • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
DBN / Key equations • Key equations: (a) (b) E*model... complex elastic modulus of the DBN model E*Say... complex elastic modulus of the Huet-Sayegh model n... chosen number of KV bodies ... pulsation (=2f with frequency f) i... complex number T... temperature ... viscosity as function of the temperature p... stress c, c,... functions of the temperature 0... 1%/min aT… temperature translation factor • Survey Models • Test Types • Required Data • Further Steps Minimisation of: SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
DBN / Input parameters • Input parameters for the model: • 3 constants for the WLF equation: C1, C2, TS • 5 constants for the linear domain: k, h, , E∞Say, E0Say • 3 constants for plastic flow: C, , C • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
DSR Visco-elastic behaviour 4 – 40 °C fatigue behaviour (SuperPave) 40 – 85 °C permanent deformation (SuperPave) • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
MACHINE LAYOUT PICTURE Simple Shear Tester • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04 36
RSST-CH perm. shear deformation h = 0 Haversine shear wave; typically 0,1sec on and 0,6sec off • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
FS-S s h=0 Sinusoidal deformation wave, typically 10, 5, 2, 1, 0.5, 0.2, 0.1, 0.05, 0.02 and 0.01 Hz • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Uniaxial and Triaxial Tests • Creep tests • The applied axial load is constant, so that specimen failure does not result from sudden load pulses. Most of these tests are run in compression states of stress. • Repeated Load Tests • A block pulse waveform that is not symmetric is applied to the specimen. One load cycle contains a load period and a rest period. • Dynamic/Cyclic Load Tests • Axial symmetric load curves are applied to the test specimen. Tests can be run in tension-compression as well as in compression only. • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Test Types / Uniaxial and Triaxial Tests • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
SERVO-HYDRAULIC TRIAXIAL TESTING MACHINE WBL0/050HH Testing Equipment at ISTU Vienna 980 kg -10 to +65 °C (14 to 149 °F) 3,1 m (122.1 in.) 1,5 m (59.1 in.) • Survey Models • Test Types • Required Data • Further Steps 1,0 m (39.4 in.) SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
PHASE LAG f SERVO-HYDRAULIC TRIAXIAL TESTING MACHINE WBL0/050HH Testing Equipment at ISTU Vienna Simulation of traffic load with AXIAL LOAD • dynamic, sinusoidal axial load CELL PRESSURE • constant cell pressure • dynamic, oscillating cell pressure – phase displaced but of same frequency; • designed to prevent radial expansion completely or in part AXIALLOAD RADIAL REACTION 42 SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
TRIAXIAL CELL Testing Equipment at ISTU Vienna • stainless steel shell, up to 20 bar • tension and compression – axial load • compression resistant grommets • installation volume measurement cell (for exact volume measuring) possible • linear controlled LVDT’s for radial strains (inside) • axial strain measuring with LVDT’s (inside/outside) • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04
Uniaxial Tension Test Test specimen shape used by Erkens in her ACRe model • Survey Models • Test Types • Required Data • Further Steps SAMARIS – Presentation Draft Deliverable 11 – WP5 Meeting Roskilde, Denmark – 23/02/04