Basics of test: Sand cylinder of mix is 10 Hz either in stress or strain a target temperature until specimen fails Test uses a

Transcription

1 Basics of test: Sand cylinder of mix is 10 Hz either in stress or strain a target temperature until specimen fails Test uses a standard Ottawa sand mesh

2 SHORT HISTORY OF TEST METHOD Dallas Little, et.al. reported on fatigue testing using molded sand mix specimens at 2002 AAPT meeting. He used a DMA in strain control and was mainly evaluating the healing effect of different binders Bahia adapted method to measure the fatigue properties of binders in a thin film matrix A stated goal is to determine fatigue properties of binders in sand mix and also in 8 mm plate-plate binder testing If sand cylinder and plate-plate rank binders the same, then use the plate-plate procedure to determine the spec value of binders

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7 OUTLINE OF TEST PROCEDURE Currently MTE has tested sand mixes made with 7% binder content using PAV residue. We have found that 100 to possibly 200 kpa is the appropriate level for most binders based on the following PG -22 & -28 grades are tested at 25 C PG -34 & (-40?) grades are tested at 20 C Frequency of 10 Hz (62.8 rad/sec) Stress of 100 kpa although we have looked at 150, 200 and 250 kpa Strain of 0.1% and 0.2% have also been evaluated Test consists of continuously oscillating the specimen at the target stress or strain level until there is peak in the G*xTime plot or until the specimen actually breaks

8 SAND CYLINDER FATIGUE, 7% WI RD ROBIN LAB 97 PAV, 25 C, 100kPa, AR1-0001o 1.50E E sec E5 1.25E E E5 1.00E E GstarxTime (PaS) 7.50E E E7 G* (Pa) % strain osc. stress (Pa) Strain = 0.206% 5.00E E E E sec =30% sec =20% time (s)

9 SAND CYLINDER FATIGUE, 5% PG PAV TK 6, , 0.1% STRAIN AR1-0005o 8.00E E8 21,440 sec E5 7.00E E E5 GstarxTime (PaS) 6.00E E E E E E E E E E E7 G* (Pa) % strain E osc stress osc. stress (Pa) 34,250 kpa E5 time (s)

10 SAND CYLINDER FATIGUE, 7% WI RD ROBIN LAB 97 PAV, 25 C, 100kPa, AR2-0002o GstarxTime (PaS) 3.00E E E E Arit. Mean 4141 Coef of Var Std. Dev E E time (s)

11 SAND CYLINDER FATIGUE, 7% PG PAV TK 100 KPA STRESS AR1-0002o GstarxTime (PaS) 3.50E E E E E Arit. Mean Coef of Var 0.22 Std. Dev E E time (s)

12 SAND CYLINDER SAND CYLINDER FATIGUE, FATIGUE, 7% PG 7% PG PAV, Elvaloy , PAV, 25C. 100KPA, AR2-0001o AR2-0001o SAND CYLINDER FATIGUE, 7% PG Elvaloy PAV, 25C. 100KPA, AR2-0002o SAND CYLINDER FATIGUE, 7% 58-34OX PAV, 25C. 100KPA, AR2-0001o, SAND CYLINDER FATIGUE, 7% 58-34OX PAV, 100kPa, AR1-0001o, 2.50E E E E E E E PMA 1124 sec 969 sec 19= 1704 GstarxTime (PaS) 1.50E E E E9 5.00E9 2.50E E E E7 G* (Pa) Ox 429 sec 276 sec time (s)

13 SAND CYLINDER SAND CYLINDER FATIGUE, FATIGUE, 7% PG 7% PG PAV, PAV, , 100kPa, 25 C 100kPa, AR1-0001o SAND CYLINDER FATIGUE, 7% PG PAV, , 25 C 100kPa, SAND CYLINDER FATIGUE, 7% PG PAV, 20C. 100 kpa SAND CYLINDER FATIGUE, 7% PG PAV, 20C. 100 kpa SAND CYLINDER FATIGUE, 7% PG PAV, , 25C. 100KPA, 7.00E E E E7 20C =3736 sec GstarxTime (PaS) 5.00E E E E E E E7 G* (Pa) 1.00E E7 25C = 911 sec time (s)

14 SAND CYLINDER SAND FATIGUE, CYLINDER FATIGUE, 7% PG 7% PG PAV, PAV, , 20C. 100kPa, kpa AR1-0001o SAND CYLINDER FATIGUE, 7% PG PAV, 20C. 100 kpa SAND CYLINDER FATIGUE, 7% FHWA 64-34SBS PAV, 20 C, 100kPa, SAND CYLINDER FATIGUE, 7% FHWA 64-34SBS PAV, 20 C, 100kPa, SAND CYLINDER FATIGUE, 7% FHWA 64-34SBS PAV, 20 C, 100kPa, 7.00E E E E C =3736 sec 5.00E E7 GstarxTime (PaS) 4.00E E E E7 G* (Pa) C =2457 sec 2.00E E7 1.00E E time (s)

15 SAND CYLINDER FATIGUE, 7% MIF PAV, 25 C, 200kPa AR2-0003o 1.00E kpa time to fail = 327 sec 8.00E9 GstarxTime (PaS) 7.00E9 6.00E9 5.00E9 4.00E9 3.00E9 2.00E time (s)

16 SAND CYLINDER FATIGUE, 7% MIF PAV, 25 C, 200kPa AR2-0003o SAND CYLINDER FATIGUE, 7% MIF PAV, 25 C, 150kPa, 9.00E E E kpa--time to fail = kpa--time to fail = 2676 sec GstarxTime (PaS) 5.00E E E E E time (s)

17 SAND CYLINDER FATIGUE, 7% MIF PAV, 25 C, 200kPa AR2-0003o SAND CYLINDER FATIGUE, 7% MIF PAV, 25 C, 150kPa, SAND CYLINDER FATIGUE, 7% MIF PAV, 100kPa, 25 C 3.00E12 GstarxTime (PaS) 2.50E E kpa--time to fail = kpa--time to fail = kpa--time to fail =64890 sec 1.00E E E5 time (s)

18 SAND SAND CYLINDER CYLINDER FATIGUE, FATIGUE, 5% 5% MIF MIF PAV, PAV, 25 C, 25 C, 250kPa, 250kPa, AR1-0001o SAND CYLINDER FATIGUE, 5% MIF PAV, 25 C, 150kPa, SAND CYLINDER FATIGUE, 5% MIF PAV, 25 C, 100kPa, GstarxTime (PaS) 9.00E9 9.00E E E9 8.00E E9 7.00E E E9 6.00E E E9 5.00E E E9 4.00E E9 3.00E kpa--time to fail = kpa--time to fail = kpa--time to fail =5594 sec 2.00E9 2.00E E E9 1.00E time (s)

19 SAND CYLINDER FATIGUE, 7% MIF PAV, 100kPa, 25 C AR2-0003o SAND CYLINDER FATIGUE, 7% PG PAV TK 100 KPA SAND CYLINDER FATIGUE, 7% PG PAV TK 100 KPA 3.00E E E12 GstarxTime (PaS) 1.50E E E E5 time (s)

20 EXAMINATION OF SOME IMPACTS OF VARYING TEMPERATURE AND OSCILLATORY STRESS LEVELS

21 SAND CYLINDER FATIGUE, 7% MIF C-35 PAV, 25 C, 100kPa, AR1-0001o SAND CYLINDER FATIGUE, 7% MIF C-35 PAV, 25 C, 150kPa, AR1-0001o 1.75E E kpa 4136 sec 1.000E E8 Gstarxglobaltime (Pas) Gstarxglobaltime (Pas) 1.50E E E E E E E E E E E9 2.50E10 Peak times E8 470 Average=647 CV= 42% Peak times E7 470 Average=647 CV= 42% 150 kpa G* (Pa) G* (Pa) E E global time time (s) (s)

22 SCF 7% C-35PAV, SCF 7% C-35PAV, 10 C, 200kPa, AR2-0001o, 10 C, 200kPa, Time sweep AR2-0001o step SCF 7% C-35PAV, 10 C, 200kPa, AR2-0001o, Time sweep step 2 SCF 3.00E12 7% C-35PAV, 10 C, 200kPa, AR2-0001o, Time sweep 1.000E9 step E E9 6.00E E9 2.50E E E12 Gstarxglobaltime (Pas) (Pas) 2.00E E E E E E E E E12 G* G* (Pa) (Pa) 1.000E8 G* (Pa) 5.00E E E E E global time (s) (s)

23 SCF 7% C-35PAV, SCF 7% C-35PAV, 10 C, 400kPa, AR2-0001o, 10 C, 400kPa, Time sweep AR2-0001o step E E9 9.00E E E11 Gstarxglobaltime (Pas) 6.00E E E E E8 G* (Pa) 2.00E E E global time (s)

24 SAND CYLINDER FATIGUE, 7% MIF C-35 PAV, 25 C, 100kPa, AR1-0001o 1.75E E E E E E9 Gstarxglobaltime (Pas) 1.25E E E E E E E E E E E E E E7 G* (Pa) E global time (s)

25 SOME COMMENTS We need to determine an appropriate stress level or do we use strain control. Strain control may be more appropriate for binders used in 50 mm or thinner pavements Need to determine if we run the test at 1 or more temps Need to determine whether to use RTFO or PAV Need to determine the appropriate % binder Too low a % binder and we may not be testing binder fatigue but rather mix strength It appears that PMA binders take a longer time to fail than non-pma binders (58-34 oxidized vs PMA It appears that PMA -28 grades take longer to fail than -28 unmodifed even though the was made from the base and both have nearly the same G value

26 SOME COMMENTS Evaluate different crude sources of straight run binders 58-28, 52-34, 64-22, Evaluate PMA grades versus non-pma grades (e.g , 70-22, 58-34, 76-28) Evaluate the same PG grades made with the same base AC but using different polymers or other additives Finally determine if the time sweep of the pure binder provides the same information as the time sweep of the sand cylinder mixes

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30 OUTLINE OF TEST PROCEDURE, cont d MTE test method is as follows: PG -22 & -28 grades are tested at 25 C PG -34 & (-40?) grades are tested at 20 C Frequency of 10 Hz (62.8 rad/sec) [Dr. Bahia is looking at 2 frequency levels based on pavement structure] Stress of 100 kpa although we have looked at 150, 200 and 250 kpa Strain of 0.1% and 0.2% have also been evaluated Test consists of continuously oscillating the specimen at the target stress or strain level until there is peak in the G*xTime plot or until the specimen actually breaks

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