CHANGE IN FATIGUE LIFE BEHAVIOR OF ASPHALT HOT MIXES PRODUCED WITH ASPHALT RUBBER BINDERS

PROF. SILVRANO A. DANTAS NETO, UNIVERSITY OF CEARA, BRAZILPROF. MÁRCIO M. DE FARIAS, UNIVERSITY OF BRASILIA, BRAZILPROF. JORGE C. PAIS, UNIVERSITY OF MINHO, PORTUGAL

1. INTRODUCTION

SUB-BASE

WEARING COURSE

BASE

SUBGRADE

CRACKING

RUTTING

1. INTRODUCTION

FATIGUE LIFE TESTS UNDER CONTROLLED STRESS

CONDITIONS:

1. INTRODUCTION

FATIGUE LIFE TESTS UNDER CONTROLLED STRAIN

CONDITIONS:

1. INTRODUCTION

( )2 31 11

t

k kN k

Eσ=

⎛ ⎞⎜ ⎟⎝ ⎠

1. INTRODUCTION

N = 7623.3st-4.199R² = 0.9695

N = 3390.9st-3.264R² = 0.9423

1.0E+01

1.0E+02

1.0E+03

1.0E+04

1.0E+05

1.0E+06

0.10 1.00 10.00

N -

Load

cyc

les

σt (MPa)

CAP 20 CAP PLUS 104

DANTAS NETO (2001):

RM = 2770 MPa

RM = 3300 MPa

THE OBJECTIVE IS TO SHOW THE CHANGE IN THE

FATIGUE LIFE OF ASPHALT HOT MIXES PRODUCED

WITH ASPHALT RUBBER BINDERS IN RELATION TO

THOSE PRODUCED WITH STRAIGHT BINDER.

DENSE GRADED ASPHALT HOT MIX;

GAP GRADED ASPHALT HOT MIX;

2. OBJECTIVE

STRAIGHT BINDER: AC 50/70

ASPHALT RUBBER BINDER (AR):

21% CRUMB RUBBER (ADOT);

DIGESTION TIME = 60 MINUTES;

TEMPERATURE OF DIGESTION = 210ºC

3. MATERIALS

3. MATERIALS

AGGREGATES:

GRADE 1 CRUSHED GRANITIC STONE: 11 – 16 mm;

GRADE 0 CRUSHED GRANITIC STONE: 4 – 11 mm;

FINE CRUSHED GRANITIC AGGREGATE: < 4 mm.

3. MATERIALS

GRAIN SIZE DISTRIBUTION OF STUDIED ASPHALT HOT

MIXES

3. MATERIALS

0

20

40

60

80

100

120

0.01 0.1 1 10

% P

assin

g

Diameter

Dense graded

Gap graded

4. PRODUCTION AND TESTING OF ASPHALT HOT MIXES

PRODUCTION:

TESTS:

5. RESULTS

CONVENTIONAL ASPHALT HOT MIXES

5. RESULTS

ASPHALT HOT MIXES x ASPHALT RUBBER HOT MIXES

1.0E+041.0E+051.0E+061.0E+071.0E+081.0E+091.0E+101.0E+11

100 1000

N (L

oad

Cycl

es)

Tensile strain (μm/m)

AC 50/70 - GG

AR - GG

1.0E+04

1.0E+05

1.0E+06

1.0E+07

1.0E+08

1.0E+09

100 1000

N (L

oad

Cycl

es)

Tensile strain (μm/m)

AC 50/70 - DG

AR - DG

5. RESULTS

ASPHALT RUBBER HOT MIXES

1.0E+04

1.0E+05

1.0E+06

1.0E+07

1.0E+08

1.0E+09

100 1000

N (L

oad

Cycl

es)

Tensile strain (μm/m)

AR - DG

AR-GG

6. CONCLUSIONS

THE RESULTS OBTAINED FOR CONVENTIONAL ASPHALT

HOT MIXES IN THIS WORK CONFIRM THE MODEL

PROPOSED BY HUANG (1993);

COMPARING THE CONVENTIONAL ASPHALT HOT MIXES

WITH THOSE PRODUCED WITH ASPHALT RUBBER

BINDER IT CAN BE OBSERVED THAT THERE WAS AN

INCREASE OF RESILIENT MODULUS AND FATIGUE LIFE

SIMULTANEOUSLY;

THE USE OF ASPHALT RUBBER BINDERS IMPROVE THE

MECHANICAL BEHAVIOR OF ASPHALT HOT MIXES

PRODUCED.

ACKNOWLEDGEMENTS

UNIVERSITY OF MINHO;

CAPES AND CNPq;

DR. JORGE B. SOUSA

CEPSA FOR SUPPLYING THE ASPHALT CONVENTIONAL BINDER;

BIOSAFE FOR SUPPLYING THE CRUMB RUBBER RECYCLED FROM

GROUND TIRES;

BARREIRAS IRMÃOS LTDA FOR SUPPLYING THE MINERAL AGGREGATES.