SAT WORKSHOP

Performance Grading Specifications

for Bituminous Binders

Development of PG Binder Specs

Kim Jenkins

tellenbosch

SAT Workshop

March 2016

• Binder blind � unmodified

� PMBs

� non-homogenous (bitumen rubber)

• Binder “fitness for purpose” in asphalt and seals

• Limit new equipment (DSR & ?)

• Address all stages & conditions of usage:� Spraying, mixing and compaction

� High temperature (permanent deformation)

� Intermediate temperature (fatigue)

� Low temperature (cracking)…if necessary

tellenbosch

Traffic Climate Durability

Primary Objectives

Fit for purpose?

Performance Grading

RV +(QC)

DSRBBR

RuttingFatigue CrackingThermal Cracking Production

- 20 0C 20 0C 60 0C 135 0CPavement Temperature

+

PG Systemcombine?

DSR Configurations8 mm diameter

2 mm

Setup for 8 mm parallel plate geometry(for frequency sweep test only)

Bitumen sample

Upper plate(rotating)

Bottom plate(fixed)

8 mm diameter

2 mm

Setup for 8 mm parallel plate geometry(for frequency sweep test only)

Bitumen sample

Upper plate(rotating)

Bottom plate(fixed)

8 mm diameter

2 mm

Gap: 0.063 mm

Setup for 8 mm cone & plate geometry(for creep-recovery test only)

Bitumen sample

Upper plate(rotating)

Bottom plate(fixed)

8 mm diameter

2 mm

Gap: 0.063 mm

Setup for 8 mm cone & plate geometry(for creep-recovery test only)

Bitumen sample

Upper plate(rotating)

Bottom plate(fixed)

Cup & Bob, CC Parallel Plate Cone & Plate

• C&B (CC) suited to viscosity η analysis

• // P variable shear stress across radius, but applicable to most situations

• C&P only necessary for strain sensitive materials

• Max 2 decades of Fr: to remain within strain tolerance?

• IT+LT damage : range of G*=100kPa-1000MPa?

CA

PS

A 2

015

Property

Proposed Classification

58S 64S 58H 64H 58V 64V 58E 64E

-22 -16 -22 -16 -22 -16 -22 -16

Maximum pavement design temperature, Tmax (˚C) 58 64 58 64 58 64 58 64

Minimum grading temperature, Tmin (˚C) -22 -16 -22 -16 -22 -16 -22 -16

Original binder

G*/sinδ, 10rads/sec at Tmax, minimum (kPa) 1.0 1.0 N/A

G*, δ, @ 0.05 to 20 rads/sec, at ([(Tmax-Tmin)/2]+4) °C Report

Viscosity (Pa.s), 135°C, maximum 3.0

Flash Point (˚C), minimum 230

Storage stability, Max % diff, G*T and G*B @Thigh 10

RTFO binder

Maximum Mass Change (m/m %) 1.0

Jnr (ASTM D7405) @ Thigh, maximum 4.5 4.5 2.0 2.0 1.0 1.0 0.5 0.5

G*, δ, @ 0.05 to 20 rads/sec, at ([(Tmax-Tmin)/2]+4)oC Report

Ageing Ratio, G*RTFOT/G*Original, maximum

(10rads/sec)3.0

PAV binder

S(60s) at Tmin + 10oC , MPa, maximum 300

m(60s) at Tmin + 10oC, minimum 0.300

∆Tc(0C), minimum -5

G*, δ, @ 0.05 to 20 rads/sec, at ([(Tmax-Tmin)/2]+4)oC Report

Ageing Ratio, G*PAV/G*Original, maximum

(10rads/sec)6.0

PG Specification Framework

High Temperature 97.5th Percentile 7 day average max.

(CSIR)

64 58

Low Temperature LT Cracking with DSR– Currently SA binder meets -16C (some -22C)

specification

(CSIR)

-7

Outcomes of Franschoek Meeting 1Production & Construction

Industry C&B or RV @ 135 oC Spec ηmax = 3Pa.sEN13702 and Anton Paar Method

Research – Currentlyunderway

Calibration RV vs C&B (JvH)

Spray, Pump, Mix, Pave

Pho

to: K

Lou

w

Effects of Visco -Elasticity inDamage Zone

Elastic

BeforeLoad

DuringLoad

AfterLoad

TyreLoad Recoverable

Deformation

Viscous

BeforeLoad

DuringLoad

AfterLoad

TyreLoad Non-Recoverable

Deformation

Permanent Deformation: Creep and Recovery (MSCR)

AASHTO TP70

Ave permanent shear strain (non-recov) per cycleApplied shear stressJnr =

Findings of PG Spec Research

D’Angelo et al

3.2kPa

Repeatability

ie Spec issues

Outcomes of Franschoek Meeting 2Permanent Deformation DCR

Industry Protocol // Plate @ τ = 0.1 & 3.2 kPa for 10cycles each (measure last 5)CSIR and AASHTO T350 methods

Trial Implementation // Plate @ τ = 0.1 & 3.2 kPa measure 10and 20 cycles

Comments For standard traffic levels, G*/sinδ should suffice, for unmodified binders P

hoto

: G v

Zyl

Dynamic Creep Recovery

Creating a Master Curve

(Rowe, 2015)

Master Curve Example unaged

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06

|G*|

(P

a)

fr (hz)

80/100 50C 80/100 25C 80/100 10C 80/100 0C CRM 50C CRM 25C CRM 10C CRM 0C

Bredenhann (2015)

Master Curve Example aged

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06

|G*|

(P

a)

fr (hz)

80/100 50C 80/100 25C 80/100 10C 80/100 0C CRM 50C CRM 25C CRM 10C CRM 0C

Bredenhann (2015)

Black Diagram unaged

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

1.E+10

0 10 20 30 40 50 60 70 80 90 100

|G*|

(kP

a)

δ (°)

80/100 50C 80/100 25C 80/100 10C 80/100 0CCRM 50C CRM 25C CRM 10C CRM 0CG-R 150 kPa G-R 450 kPa

Bredenhann (2015)

Black Diagram aged

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

0 10 20 30 40 50 60 70 80 90 100

|G*|

(kP

a)

δ (°)

80-100 50C 80-100 25C 80-100 10C 80-100 0CCRM 50C CRM 25C CRM 10C CRM 0CG-R 150 kPa G-R 450 kPa

Bredenhann (2015)

Master Curve

(Rowe, 2015)

ReferenceTemperature

Master Curve from different tests

(Rowe, 2015)

deflection

Master Curve from different tests

(Rowe, 2015)

deflection

Durability Cracking

• Testing at IT and LT

• Parameters Consider R, ∆Tc , G-R parameter,

etc

deflection

Load

DSR (4mm) BBR

Notes for Durability Tests

DSR for s,m: COV=40%, more expensive, less bit, BR?

BBR for s,m: COV=4%, cheaper, more binder, non-homog

Note

Tmin = -160C is a durability check

NOT at test at -160C !!

23

Log CreepStiffness, S

Log Loading Time

slope = m-value

60 sec8 15 30 120 240

S(60)m(60)

Results of Bending Beam Rheometer

Thermal

Stress build up

Thermal

Stress relaxation

∆TC = TS - Tm = measure of loss in relaxation properties,

taking account of binder ageing

• ∆Tc – shown in both time [top right] domain and temperature domain [bottom right]

• ∆Tc – can be computed from BBR MC analysis

• Same concept can be derived from dynamic data with interrelationship

∆Tc approach

24

Which characteristics define

the onset of cracking?

Rate of ageing

Relaxation properties

What causes thermal cracking?

T1

Stress Relaxation α m(60)

Temp

Thermal

Stress or

strain

Fracture stress or

strain

Stress α S(60)

T2

Effective Stresses Small S(60)

high m (60)

are better

Cracking: Glover-Rowe Parameter

G* Test Parameters @ T=150C and Fr = 0.005 rad/sec

Performance Graded Binders for South Africa

Stellenbosch – South Africa , June 13, 2014

www.uwmarc.org

Parameters for IT and LT damage

DSR Parameters: R (Master Curve), G-R parameter (Black Diagram)

(Rowe, 2015)

(Rowe)

G* δ

Durability Cracking

Industry BBR test for S (60) and m (60)∆Tc min = -5 0C

Industry report DSR //P @ Strain sweep G*, δ, @ 0.05 to 20 rads/sec, at ([(Tmax-Tmin)/2]+4)oC

Evaluate R, G-R parameter from DSR data

Pho

to: C

SIR

Stress relaxation properties for IT and LT damage

Property

Proposed Classification

58S 64S 58H 64H 58V 64V 58E 64E

-22 -16 -22 -16 -22 -16 -22 -16

Maximum pavement design temperature, Tmax (˚C) 58 64 58 64 58 64 58 64

Minimum grading temperature, Tmin (˚C) -22 -16 -22 -16 -22 -16 -22 -16

Original binder

G*/sinδ, 10rads/sec at Tmax, minimum 1.0 1.0 N/A

G*, δ, @ 0.05 to 20 rads/sec, at ([(Tmax-Tmin)/2]+4) °C Report

Viscosity Pa.s, 135°C, Pa.s, maximum 3.0

Flash Point (˚C), minimum 230

Storage stability, Max % diff, G*T and G*B @Thigh 10

RTFO binder

Maximum Mass Change (m/m %) 1.0

Jnr (ASTM D7405) @ Thigh, maximum 4.5 4.5 2.0 2.0 1.0 1.0 0.5 0.5

G*, δ, @ 0.05 to 20 rads/sec, at ([(Tmax-Tmin)/2]+4)oC Report

Ageing Ratio, G*RTFOT/G*Original, maximum

(10rads/sec)3.0

PAV binder

S(60s) at Tmin + 10oC , MPa, maximum 300

m(60s) at Tmin + 10oC, minimum 0.300

∆Tc(0C), minimum -5

G*, δ, @ 0.05 to 20 rads/sec, at ([(Tmax-Tmin)/2]+4)oC Report

Ageing Ratio, G*PAV/G*Original, maximum

(10rads/sec)6.0

PG Specification Framework

DSR BBR

Benefits of PG Spec for SA?

• Binder selection based on traffic, climate

• Product innovation reliably assessed eg PMBs

• Permanent deformation reliably evaluated

• Long Term Ageing finally assessed, for thin layers in SA context!!

• Durability – stress relaxation holistically assessed (not fatigue versus LT fracture)

• Resource economy in test apparatus & methods (but bitumen sample size IT and LT!)

• No binder grade proliferation

The future is

so bright, I

need shades.

Thank you!