EFFECT OF CRUMB RUBBER ON THE RHEOLOGICAL PROPERTIES OF ASPHALTS AFTER LONG-TERM OXIDATIVE AGING

Transcription

1 EFFECT OF CRUMB RUBBER ON THE RHEOLOGICAL PROPERTIES OF ASPHALTS AFTER LONG-TERM OXIDATIVE AGING Shin-Che Huang Symposium on Additives Used in Asphalt Pavements Laramie, Wyoming June 23-25, 2004

2 LITERATURE Arizona Chip seal (SAM, SAMI) (TRB 1307) Retarded reflective crack propagation in overlays Reduced spalling of AC around potholes and larger cracks. Arkansas Plusride (TRB 1639, 1998) Improved fatigue resistance Minimized bleeding because the rubber and asphalt combine to form a more elastic binder.

3 LITERATURE Calfornia Plusride and SAM (1988) Reduced reflective cracking Thinner sections of rubberized asphalt concrete have outperformed thicker sections of densegraded asphalt concrete hot mixes. Cost effective (1997) Florida Open-graded surface mixes Improved durability and pavement life.

4 LITERATURE Texas Wet process (SAM, SAMI) (1996) Reduced fatigue and thermal cracking of AC pavements. Minnesota Plusride Overlays (1988) Moisture sensitivity of CRM mixtures was similar to the unmodified mixtures. CRM mixtures showed greater ability to dissipate stress through strain. Problems with raveling.

5 LITERATURE United Kingdom Dry Process (3 rd E&E Congress) Better fatigue resistance. Worse permanent deformation. Large reduction in asphalt mixture stiffness. Italy Dry process (3 rd E&E Congress) Reduction of phase angle. Enhanced the fatigue resistance. Increased the elasticity. Enhanced the rutting resistance.

6 LITERATURE--SUMMARY Asphalt-rubber pavements, in general, will perform better than conventional asphalt pavements. Reduce traffic noise. Reduce reflective cracking Reduce fatigue cracking. Reduce thermal cracking. Reduce rutting potential. Moisture sensitivity is the same as regular mixes.

7 LITERATURE--SUMMARY Asphalt-rubber pavements, in general, will perform better than conventional asphalt pavements. Reduce traffic noise. Reduce reflective cracking Reduce fatigue cracking. Reduce thermal cracking. Reduce rutting potential. Moisture sensitivity is the same as regular mixes. Cost effective??? Long-term aging???

8 OBJECTIVE To determine how the rheological properties of rubber-treated asphalts varied with aging time when compared with untreated asphalts aged at temperatures in the pavement temperature range.

9 EXPERIMENTAL DESIGN Materials Asphalts AAD-1 and ABD GF40 PAV Asphalts mixed with 13.3 mass % rubber PAV at 60 C at 2.1 MPa for 100, 400, 800, and 2000 hrs.

10 ASPHALT PROPERTIES (MRL Library) AAD-1 ABD SHRP PG Grade PG58-28 PG C (poise) Asphaltene (n-heptane) Polar aromatic Napthene aromatic Saturate Element Sulfur (mass, %) Vanadium, ppm Nitrogen, % Oxygen, % Functional Group Carboxylic acids Sulfoxides

11 EFFECT OF ASPHALT ON AGING KINETIC Complex Viscosity at 10 rad/sec, Pa s 1e+7 1e+6 1e+5 1e O Time in PAV at 60 C, hrs

12 EFFECT OF RUBBER ON AGING KINETIC Complex Viscosity at 10 rad/sec, Pa s 1e+7 1e+6 1e+5 1e O Time in PAV at 60 C, hrs

13 EFFECT OF RUBBER ON AGING KINETIC Complex Viscosity at 10 rad/sec, Pa s 1e+5 1e+4 1e+3 1e O Time in PAV at 60 C, hrs

14 EFFECT OF RUBBER ON CHANGE IN PHASE ANGLE 80 Phase Angle at 10 rad/sec O Time in PAV at 60 C, hrs

15 100 EFFECT OF RUBBER ON CHANGE IN PHASE ANGLE Phase Angle at 10 rad/sec O Time in PAV at 60 C, hrs

16 EFFECT OF RUBBER ON AGING KINETIC Complex Vixcosity at 0.1 rad/sec, Pa s 1e+8 1e+7 1e+6 1e+5 1e O Time in PAV at 60 C, hrs

17 EFFECT OF RUBBER ON AGING KINETIC Complex Vixcosity at 0.1 rad/sec, Pa s 1e+5 1e+4 1e+3 1e+2 1e O Time in PAV at 60 C, hrs

18 80 EFFECT OF RUBBER ON CHANGE IN PHASE ANGLE Phase Angle at 0.1 rad/sec O Time in PAV at 60 C, hrs

19 100 EFFECT OF RUBBER ON CHANGE IN PHASE ANGLE Phase Angle at 0.1 rad/sec O Time in PAV at 60 C, hrs

20 Complex Viscosity, Pa s EFFECT OF RUBBER ON SHEAR SUSCEPTIBILITY 1e+7 1e+6 1e+5 1e+4 1e+3 Unaged, 25 C Data Neat AAD-1 AAD-1/13.3% Rubber Neat ABD ABD/13.3% GF40 1e Frequency, rad/s.

21 Complex Viscosity, Pa s EFFECT OF RUBBER ON SHEAR SUSCEPTIBILITY Unaged, 60 C Data Neat AAD-1 AAD-1/13.3% Rubber Neat ABD ABD/13.3% Rubber Frequency, rad/s.

22 Complex modulus, Pa s 1e+8 1e+7 1e+6 1e+5 1e+4 1e+3 EFFECT OF RUBBER ON BLACK PLOT Neat AAD-1 AAD-1/13.3% Rubber Neat ABD ABD/13.3% Rubber 1e Phase Angle, degree Unaged, 25 C Data

23 Complex Modulus, Pa s 1e+8 1e+7 1e+6 1e+5 1e+4 1e+3 EFFECT OF OXIDATION ON BLACK PLOT PAV for 800 hrs 25 C Data Neat AAD-1 AAD-1/13.3% Rubber Neat ABD ABD/13.3% Rubber 1e Phase Angle, degree

24 1E+05 EFFECT OF RUBBER ON MASTER CURVES ABD Complex Modulus (kpa) 1E+04 1E+03 1E+02 1E+01 ABD/13.3% RUBBER AAD-1 AAD-1/13.3% RUBBER 1E+00 1E-04 1E-02 1E+00 1E+02 1E+04 1E+06 1E+08 Reduced Frequency (rad/s.)

25 Complex Modulus, Pa 1e+8 1e+7 1e+6 1e+5 1e+4 1e+3 EFFECT OF OXIDATION ON BLACK PLOT Neat AAD-1 AAD-1/13.3% Rubber Neat ABD ABD/13.3% Rubber 1e Phase Angle, degree PAV for 400 hrs 25 C Data

26 1E+05 MASTER CURVE OF ASPHALT AAD-1 Complex Modulus, kpa 1E+04 1E+03 1E+02 1E+01 1E+00 1E-04 1E-02 1E+00 1E+02 1E+04 1E+06 1E+08 Frequency, rad/s.

27 EFFECT OF RUBBER ON CHANGE IN MASTER CURVES OF PHASE ANGLE ABD Phase Angle (deg) AAD-1/13.3 % RUBBER ABD/13.3 % RUBBER AAD E-04 1E-02 1E+00 1E+02 1E+04 1E+06 1E+08 Reduced Frequency (rad/s.)

28 EFFECT OF RUBBER ON SHIFT FACTOR log a t O Time in PAV at 60 C, hrs

29 CONCLUSIONS The results indicated that the addition of crumb rubber to asphalt binder increases the binder viscosity and improved the resistance of the binder to aging. The obvious benefit of adding crumb rubber to asphalts AAD-1 and ABD is that the rubber imparts greater elasticity to the binder that helps increase fatigue resistance. The pavement is more flexible, thus improving its susceptibility to low-temperature cracking.

30 ACKNOWLEDGEMENTS The authors gratefully acknowledge the Federal Highway Administration, U.S. Department of Transportation, for financial support of this project under contract no. DTFH61-99C

31 ACKNOWLEDGEMENTS Mr. Joe W. Button, Texas Transportation Institute Dr. J. Claine Petersen James Beiswenger, Janet Wolf, and Steve Salmans

32 DISCLAIMER This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The United States government assumes no liability for its contents or use thereof. The contents do not necessarily reflect the official views of the policy of the U.S. Department of Transportation.