DETERMINATION OF MIXING AND COMPACTION TEMPERATURE OF PG BINDERS USING A STEADY SHEAR

FLOW TEST

1111

STEADY SHEAR FLOW TEST (SSF)•Using a 250 or 500 micron gap, 25 mm diameter plate we test at 76, 82, 88 & 94° C (we have settled on 500 µ as the most utilitarian; at 1000 µ material drains from between plates)

•We use a TA Instruments AR2000 with an environmental test chamber (air controlled), but any rheometer capable of performing steady shear flow should be able to perform the test.•0.5 to 1500 µN·m of torque (.16-489 Pa stress)•Log mode 5 points per decade•Maximum test time for each point of 12 minutes and test moves on to next torque level•3 consecutive points within 2% of each other and the test moves on to the next torque level

The following slide (slide 4) shows the results of a completed test on a PG 64-34 PMA binder. The data shows the viscosity decrease as test temperature increases and furthermore shows the decrease in viscosity at a given temperature as the shear stress increases.

Even though PG 64-34 is a fairly heavily modified binder this data shows that as shear stress increases at a given temperaturethe resulting apparent viscosity tends to a constant value. We have determined that by using these steady state values we can calculate realistic values for mixing and compaction temperature.

0 100.0 200.0 300.0 400.0 500.0 600.0shear stress (Pa)

0

50.00

100.0

150.0

200.0

250.0

300.0

350.0

visc

osity

(Pa.

s)MIF 03-06-20-64-34-36 UNAGED SSF 250 micron gap-0001f-2

The comments which follow apply to the next 2 slides (6&7)

Slide 6 is a log-log plot of apparent viscosity versus shear stress. This material is well behaved and the data follows a classic pattern of a viscous plateau (zero shear or low shear viscosity value) at low shear stress and shear thinning region as the stress increases. If we could generate such well behaved data for all samples then zero shear viscosity could potentially be used as a basis for determining mixing and compaction temperature

Slide 7 shows more typical data for a different PG 64-34. At the low shear rates the material has failed to reach steady state and it is impossible to know what the zero shear value would be.

0.1000 1.000 10.00 100.0 1000shear stress (Pa)

10.00

100.0

1000

10000vi

scos

ity (P

a.s)

Carreaua: zero-rate viscosity: 1766 Pa.sb: infinite-rate viscosity: 3.749E-3 Pa.sc: consistency: 282.1 sd: rate index: 0.4120 standard error: 4.457 thixotropy: 0 Pa/snormalised thixotropy: 0 1/sEnd condition: Finished normally

Williamsona: zero-rate viscosity: 2165 Pa.sb: consistency: 110.4 sc: rate index: 0.5112 standard error: 27.68 thixotropy: 0 Pa/snormalised thixotropy: 0 1/sEnd condition: Finished normally

88 CVIS @ 409 Pa = 94.61 Pa.s

64-34, Unaged, SSF FOR ZSV 82°C-94°C, 500gap-0001f-3

1.000E-4 1.000E-3 0.01000 0.1000 1.000 10.00 100.0shear rate (1/s)

1.000

10.00

100.0

1000vi

scos

ity (P

a.s)

FHWA 64-34 KTR101 UNAGED, SSF for ZSV 76-94°C, 500gap AR2-0001f

MIXING AND COMPACTION TEMPERATURE DETERMINATION PROCEDURE

•Determine viscosity using a DSR Steady State Flow test at 76°, 82° C, 88° C, & 94° C as outlined in slide 2

•Use plate-plate geometry and 500 micron gap

•Plot log viscosity (@ 409 Pa) versus log temperature and extrapolate the results to a temperature of 180° C

•Determine mixing temperature where viscosity = 150-190 centipoise (.15-.19 Pa.s)

•Determine compaction temperature where viscosity =320-380 centipoise (.32-.38 Pa.s)

The following data plot (slide 10) shows a PG 58-28 tested over the range of 76° C to 94° C at a range of stress levels.

Because the 58-28 is unmodified the viscosity very quickly achieves a nearly constant value at each temperature. (i.e. Newtonian)

0 50.00 100.0 150.0 200.0 250.0 300.0 350.0 400.0 450.0 500.0shear stress (Pa)

1.000

10.00

100.0

visc

osity

(Pa.

s)MIF 58-28 11-4-02 TK5, SSF FOR ZSV 76-94°C, 250 micron gap-0001f

Viscosity valuesat 409 Pascals

10101010

The following data plot (slide 10) shows a PG 58-28 tested over the range of 76° C to 94° C at a range of stress levels.

Because the 58-28 is unmodified the viscosity very quickly achieves a nearly constant value at each temperature, (i.e.Newtonian)

The next slide (slide 12) shows the DSR results, the extrapolated data and the Brookfield results. Note that for this material the Brookfield data and the extrapolated data overlay. This should be expected since the 58-28 is unmodified.

11111111

1

10

100

1000

1E+04

1E+05

VIS C

OSI

TY IN

CPS

50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 889092949698100

120

140

160

180

200

TEMPERATURE IN DEG C

Log10(Y) = 15.4452 - 6.10776Log10(X)EMS = 5.15599e-006R2 = 1.000

Log10(Y) = 16.7304 - 6.70317Log10(X)EMS = 2.2716e-005R2 = 1.000

EXTRAPOLATION BASED ON DSR DATABROOKFIELD DATASTEADY SHEAR VIS DATA AT 409 Pascal STRESS

BROOKFIELD RESULTSMIX TEMP = 343 FCOMPACTION TEMP = 321.6 F

PG 58-28

MID POINT OF MIXING TEMP RANGE = 146 C /295 FMID POINT OF COMPACTION RANGE = 131 C/268 F

07/14/03 00:22:39 E:\AR2000\RESULTS\2003\ZSV SSF TESTING\PG 58-28 ZSV WORK BASED ON DIFFERENT TEST PROCEDURES.SPF

12121212

The following data plot (slide 14) shows a PG 64-34 tested over the range of 82° C to 94° C at a range of stress levels.

Because the 64-34 is polymer modifed the viscosity at low stress levels is quite high and then begins to level off at highapplied stress levels.

The zoomed scale slide (slide 15) shows that even at 409 Pascals the viscosity is not quite constant.

13131313

0 50.00 100.0 150.0 200.0 250.0 300.0 350.0 400.0 450.0 500.0shear stress (Pa)

0

1000

2000

3000

4000

5000

6000

visc

osity

(Pa.

s)

SBS MODIFIED 64-34, Unaged, SSF FOR ZSV 82°C-94°C, 500gap-0001f-2

14141414

0 50.00 100.0 150.0 200.0 250.0 300.0 350.0 400.0 450.0 500.0shear stress (Pa)

0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

800.0

900.0

1000

visc

osity

(Pa.

s)

SBS MODIFIED 64-34, Unaged, SSF FOR ZSV 82°C-94°C, 500gap-0001f-2

ZOOMED SCALE

15151515

The following data plot (slide 14) shows a PG 64-34 tested over the range of 82° C to 94° C at a range of stress levels.Because the 64-34 is polymer modifed the viscosity at low stress levels is quite high and then begins to level off at highapplied stress levels. The zoomed scale slide (slide 15) shows that even at 409 Pascals the viscosity is not quite constant.The next slide (slide 17) shows the mixing and compaction temperature results based on extrapolated data and the values that the Brookfield would predict. As we would expect there is significant difference between these results

16161616

1

10

100

1000

1E+04

1E+05

1E+06

1E+07

VISC

OS I

TY IN

CP S

50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86889092949698100

120

140

160

180

200

TEMPERATURE IN DEG C

Log10(Y) = 27.5527 - 11.6067Log10(X)EMS = 9.03714e-005R2 = 1.000

PG 64-34 SBS POLYMER MODIFIEDBROOKFIELD MIXING >195 C/383 FBROOKFIELD COMPACTION = 185 C/365 FDSR EXTRAPOLATED RESULTMID POINT OF RANGEMIXING TEMP 152.6 C/306 FCOMPACTION TEMP = 143 C/ 289 F

17171717

The next slide (slide 19) shows mixing and compaction results for a PG 64-34 which we tested using both a 250 µ and 500 µ gap. As you can see from these data, the results are nearly identical. The only reason for ultimately choosing a 500 µ gap was because of the very high viscosity of some highly modified binders and because some PMA’s can have dispersed particles with diameters approaching 60 µ (1/4 the value of 250 µ)

18181818

1

10

100

1000

1E+04

1E+05

1E+06

VISC

OSI

TY IN

CPS

50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 9092949698100

120

140

160

180

200

TEMPERATURE IN DEG C

Log10(Y) = 17.8247 - 6.93041Log10(X)EMS = 0.00067418R2 = 0.994

Log10(Y) = 25.8352 - 10.7708Log10(X)EMS = 0.000587813R2 = 0.998Log10(Y) = 25.5676 - 10.668Log10(X)EMS = 0.000300143R2 = 0.999

BROOKFIELD RESULTS FOR 64-34 ELVALOY BINDERDSR SSF RESULTS USING 250 µ GAPDSR SSF RESULTS USING 500 µ GAP

PG 64-34 ELVALOY POLYMERMIX AND COMPACTION RANGE USING SSF @ 500 µMIXING = 309--315°FCOMPACTION = 290--297°F

BROOKFIELD RESULTMIXING = 347--358°FCOMPACTION = 326--334°F

09/01/03 10:24:22 E:\AR2000\RESULTS\2003\ZSV SSF TESTING\PG 64-34 ELVALOY poly ZSV WORK BASED ON DIFFERENT TEST PROCEDUR

19191919

Slides 21-23 show mixing and compaction results for several different polymer modified binders. These are just examples showing the range of results than are possible depending on the type of polymer, the PG grade produced and the base asphalt employed. Because all of these factors will ultimately affect the final mixing and compaction values, trying to arrive at “typical” values for each PG grade will at best be an approximation.

20202020

1

10

100

1000

1E+04

1E+05

1E+06

VIS C

OSI

TY I N

CPS

50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98100

120

140

160

180

200

TEMPERATURE IN DEG C

Log10(Y) = 20.4759 - 8.16534Log10(X)EMS = 1.15886e-005R2 = 1.000 PG 70-28 POLYMER

MIXING RANGE 336-345 FCOMPACTION RANGE 310-320 F

08/13/03 11:12:16 C:\DRIVE_E DATA\AR2003\ZSV SSF TESTING\PG 70-28 ZSV WORK BASED ON DIFFERENT TEST PROCEDURES.SPF

21212121

1

10

100

1000

1E+04

1E+05

VISC

OS I

TY IN

CP S

50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 889092949698100

120

140

160

180

200

TEMPERATURE IN DEG C

Log10(Y) = 18.9617 - 7.59698Log10(X)EMS = 0.00011372R2 = 0.999

PG 64-34 WITH SBS

PG 64-34 POLYMER

MIXING RANGE 314-323 FCOMPACTION RANGE 288-298 F

08/13/03 11:18:49 C:\DRIVE_E DATA\AR2003\ZSV SSF TESTING\PG 64-34P ZSV WORK BASED ON DIFFERENT TEST PROCEDURES.SPF

22222222

1

10

100

1000

1E+04

1E+05

VIS C

OSI

TY I N

CPS

50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86889092949698100

120

140

160

180

200

TEMPERATURE IN DEG C

Log10(Y) = 18.5756 - 7.39438Log10(X)EMS = 1.47328e-005R2 = 1.000

EXTRAPOLATION BASED ON DSR DATA

PG 64-28 SENT TO UW MADISON

MIXING RANGE 320-329 FCOMPACTION RANGE 292-303 F

08/13/03 11:23:42 C:\DRIVE_E DATA\AR2003\ZSV SSF TESTING\PG 64-28P SENT TO MADISON ZSV WORK BASED ON DIFFERENT TEST P

23232323