OPTIMUM TESTING CONDITIONS TO MEASURE HMA FATIGUE …docs.trb.org/prp/12-1266.pdf · 1 OPTIMUM...

OPTIMUM TESTING CONDITIONS TO MEASURE HMA FATIGUE AND HEALING 1

USING FLEXURAL BENDING TEST 2

3

4 Michael Mamlouk, Ph.D., P.E., F.ASCE* 5

Professor 6

Civil, Environmental and Sustainable Engineering Program 7

Arizona State University 8

P.O. Box 875306, Tempe, AZ 85287-5306 9

Phone: (480) 965-2892 10

Fax: (480) 965-0557 11

E-mail: [email protected] 12

13 Mena Souliman, M.S., Ph.D. Candidate 14

Graduate Research Associate 15



P.O. Box 875306, Tempe, AZ 85287-5306 18

Phone: (480) 965-5512 19

Fax: (480) 965-0557 20

E-mail: [email protected] 21

22

Waleed Zeiada, M.S., Ph.D. Candidate 23

Graduate Research Associate 24



P.O. Box 875306, Tempe, AZ 85287-5306 27

Phone: (480) 965-5512 28

Fax: (480) 965-0557 29

Assistant Lecturer, Faculty of Engineering, Mansoura University, Mansoura, Egypt. 30

E-mail: [email protected]; [email protected] 31

32

33

*Corresponding author 34 35

Submitted for Presentation and Publication at the 91st Annual Meeting of the Transportation 36

Research Board 37

Submit date: July 31st, 2012 38

Word Count: 4189 + 2500 = 6689 39

Number of Tables: 0 40

Number of Figures: 10 41

42

TRB 2012 Annual Meeting Paper revised from original submittal.

Mamlouk, Souliman, and Zeiada 1

ABSTRACT 1

The beam fatigue test of hot-mix asphalt (HMA) has been used for nearly a half century. 2

However, several conflicting results have been recently reported. This study attempts to 3

optimize the test conditions such as waveform type (haversine vs. sinusoidal), incorporating rest 4

periods between loading cycles and the effect of rest period on the healing of the HMA to 5

minimize (eliminate) gross errors in the data analysis of the fatigue test results. In the deflection-6

controlled haversine test (ASTM D-7460) permanent deformations lead to a new equilibrium 7

neutral position of the beam and the force output follows a sinusoidal waveform. This tends to 8

bend the beam in both directions similar to the deflection-controlled sinusoidal test. This would 9

produce erroneous fatigue results since the test assumptions do not match the actual test 10

conditions. In contrast, the deflection-controlled sinusoidal test (AASHTO T-321) is more 11

consistent than the deflection-controlled haversine test (ASTM D-7460). When tests, with and 12

without rest periods, are compared for healing type of studies, it is even more important to use a 13

deflection-controlled sinusoidal test in order to obtain a fair comparison and accurate healing 14

results. Since neither the haversine waveform nor the sinusoidal waveform in the lab exactly 15

simulates field conditions, it is important to use a sinusoidal waveform in order to obtain 16

consistent results. It is recommended that ASTM changes the ASTM D-7460 designation and 17

test procedure to require a deflection-controlled sinusoidal waveform instead of haversine. 18

19

20



INTRODUCTION 1

Beam fatigue (four point bending) testing of hot-mix asphalt (HMA) in the laboratory (Figure 1) 2

has been used for several decades by many researchers to simulate field conditions. It is 3

anticipated that the test will gain wider acceptance since it forms the foundation of the fatigue 4

analysis used in the Mechanistic-Empirical Pavement Design Guide (1). In this test, a HMA 5

beam is subjected to repeated bending until it fails. The stiffness ratio is calculated by dividing 6

the current stiffness, at a given level of repetitions (cycles), by the initial stiffness. The number 7

of loading cycles at failure is recorded and plotted against the strain value. Normally 8 to 12 8

specimens are tested at different strain or stress levels to establish the fatigue relationship at a 9

specific temperature. Since the stiffness of HMA is largely affected by temperature, the test is 10

typically performed at several temperatures to evaluate the effect of stiffness on the fatigue life. 11

12

13

14

15

16

17

18

19

20

21

22

FIGURE 1 Beam fatigue apparatus 23

Historically, haversine and sinusoidal waveforms have been used in the beam fatigue test 24

on HMA. Most researchers (8, 10, 11, 12, 13, 14), especially in the U.S., have been applying a 25

haversine waveform under either controlled deflection (strain) or controlled force (stress) mode 26

for several decades. Also, the literature indicates that most researchers have run the beam 27

fatigue test without a rest period between load cycles. 28

With the advanced computer and equipment technology that has been developed in recent 29

years, researchers have been able to examine the pulse shapes in more detail. Therefore, recent 30

literature has emerged to show erroneous results, such as inconsistent waveforms or unexpected 31

fatigue results. Pronk et al (1, 2) showed that beam fatigue tests with a constant haversine 32

deflection on HMA would immediately change into tests with constant sinusoidal deflections 33

performed on a bent beam. They even went one step further and concluded that it is not possible 34



to carry out fatigue bending tests where both a haversine stress (force) oscillating signal and a 1

haversine strain (displacement) oscillating signal are maintained throughout the test because of 2

the viscoelastic (viscous part) character of asphalt. This implies that a haversine test in a HMA 3

beam would result in erroneous fatigue results since a haversine force does not have the same 4

effect on fatigue as a sinusoidal force with the same peak-to-peak value. The haversine force 5

results in tension at the bottom of the beam and compression at the top, whereas the sinusoidal 6

force results in reversible tension and compression at the top and bottom of the beam with half of 7

the stress magnitude as that produced by the haversine force. Also, tension reduces the fatigue 8

life of the beam, while compression may tend to heal fatigue cracks. 9

Pronk‟s claim is rather serious because it affects a well-established standardized test procedure 10

(ASTM D-7460) that has been used by many researchers throughout the last five decades. 11

Although not explicitly discussed in their papers, the results of other researchers (3, 4) imply that 12

when a haversine deflection-controlled test is run on a HMA beam the wave pulse changes to 13

sinusoidal, which support Pronk‟s claim. Therefore, it is important to verify Pronk‟s claim under 14

different conditions. Also, it is important to verify this claim for tests with and without rest 15

periods between loading cycles and investigate the effect of the waveform on healing. Optimum 16

test conditions for the beam fatigue test are needed that would ensure accurate fatigue results and 17

confirm the healing that could happen to the HMA during the rest periods. 18

OBJECTIVE 19

The objective of this study is to determine the optimum conditions for deflection-controlled 20

beam fatigue testing of HMA. Issues studied include the applied pulse shape (haversine versus 21

sinusoidal), the incorporation of rest periods between loading cycles, and the effect of rest period 22

on the healing of the HMA. 23

BACKGROUND 24

Types of Beam Fatigue Test 25

Deflection-controlled beam fatigue tests can be performed using either a haversine waveform 26

(ASTM D-7460) or a sinusoidal waveform (AASHTO T-321). Figure 2 shows the input 27

haversine and sinusoidal waveforms in the beam fatigue test without rest periods. The haversine 28

waveform tends to bend the beam downward in one direction, whereas the sinusoidal waveform 29

tends to bend the beam upward and downward with half of the magnitude of the haversine in 30

each direction. In the last several years, researchers have also started performing the beam 31

fatigue test with rest periods between loading applications to evaluate the healing effect that may 32

occur during the rest period. From this, estimates of the presence of an endurance limit have 33

been investigated (5, 6, 7). 34

35



1

FIGURE 2 Haversine and sinusoidal input waveforms without rest periods 2

3

Rest Period and Healing Concept 4

Although the continuous loading cycles without rest periods do not accurately simulate actual 5

traffic loading, it has been the most dominant procedure due to testing time constraints. Some 6

researchers, however, introduce a rest period after each loading cycle in order to simulate traffic 7

loading in the field (8, 9, 10). A typical loading pulse is 0.1 second and typical rest periods 8

range from 0.1 – 19 seconds. Introducing rest periods during the fatigue test allows the HMA 9

material to heal some of micro cracks caused by the load due to the viscous nature of the 10

material. Figure 3 shows a schematic of the stiffness ratio (current stiffness/initial stiffness) 11

versus loading cycles with and without rest period. The difference between the two curves can 12

be used as a measure of healing. 13

14

15

FIGURE 3 Number of cycles vs. stiffness ratio with and without rest periods 16



Several researchers have studied the significance of rest periods between load applications 1

during fatigue testing of HMA. Researchers showed a general enhancement of the fatigue life 2

when introducing rest periods (8, 10, 11, 12, 13, 14). Some researchers reported an increase in 3

fatigue life as much as 25 times (15). The optimum rest period would be different based on 4

mixture properties (aggregate gradation, binder content, binder grade, mixture volumetric, etc.) 5

and test conditions (mode of loading, temperature, frequency, stress or strain levels, etc). Other 6

researchers (19) stated that fatigue life can be explained by other phenomena: nonlinearity, 7

heating, thixotropy and fatigue. Analysis reported by Benedetto (19) showed that the two 8

reversible effects (heating and thixotropy) are very important and can not be ignored when 9

interpreting fatigue tests. Nonlinearity was also shown to be reversible. Heating is due to the 10

viscous dissipated energy that heats the specimen. 11

12

EXPERIMENTAL TESTS 13

Deflection-controlled haversine and sinusoidal flexural fatigue tests were performed on HMA 14

beams according to ASTM D-7460 and AASHTO T-321, respectively, using two IPC machines 15

(Figure 1). Tests with and without rest periods were performed on a densely-graded base mix 16

with a nominal maximum size aggregate of 3/4 inch and a PG 64-22 binder (16). The haversine 17

and sinusoidal waveforms had the same strain pulse of 0.1 seconds. Two strain levels of 400 and 18

800 microstrains and three test temperatures of 4, 21 and 38oC (40, 70 and 100 F) were used. 19

Fatigue Tests without Rest Periods 20

In this part of the study, deflection-controlled haversine (ASTM D-7460) and sinusoidal 21

(AASHTO T-321) flexural fatigue tests were performed. The shape of the force pulses was 22

examined for both haversine and sinusoidal waveforms during the test. Figure 4 shows an 23

example of several cycles of input deflection and the resulting force response during the test 24

without rest period. For the sinusoidal test, both the deformation input and the resulting force 25

follow sinusoidal waveforms. For the haversine test, however, the deflection input remains as 26

haversine, while the force output follows a sine waveform. This means that although the input 27

deflection tries to bend the beam in one direction, the beam actually bends in both directions. 28

This also implies that the stress output, and the resulting strain, are sinusoidal. In other words, 29

the deformation input follows a haversine waveform, while the strain follows a sinusoidal 30

waveform. 31

Figure 5 shows an example of the force output versus time for haversine and sinusoidal 32

tests with the same input peak-to-peak deflection using the same strain level and test 33

temperature. The figure shows that although the input waveforms are different, the force outputs 34

are almost the same for the two tests. This also definitely confirms Pronk‟s claim that it is not 35

possible to carry out fatigue bending tests where both a haversine stress (force) oscillating signal 36

and a haversine strain (displacement) oscillating signal are maintained throughout the test. 37

38


Mamlouk, Souliman, and Zeiada 6 Force and Deflection vs. Time (3 consecutive cycles)

(70F, 800 s, 0 sec RP, Strain-Controlled, Sinusoidal)

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

1498.9 1499 1499.1 1499.2 1499.3 1499.4

Time

Fo

rce

, k

N

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

De

fle

cti

on

, m

m

Deflection-

Input

Force-

Output

1 (a) Sinusoidal 2

3 (70F, 800 s, 0 sec RP, Strain Controlled)

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

1498.8 1499 1499.2 1499.4 1499.6 1499.8

Time, sec

Fo

rce

, k

N

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

Force-

Output

Deflection-

Input

Defl

ecti

on

, m

m

4 (b) Haversine 5

FIGURE 4 Force and deflection vs. time for sinusoidal and haversine deflection controlled 6

tests without rest periods (800 microstrains, 21oC) 7

8


Mamlouk, Souliman, and Zeiada 7 Force vs. Time (3 consecutive cycles)

(70F, 400 ms, 0 sec RP, Strain-Controlled, Haversine vs Sinusoidal)

-0.8

-0.4

0

0.4

0.8

1498.9 1499 1499.1 1499.2 1499.3 1499.4

Time

Fo

rce

, kN Haversine

Sinusidal

1

FIGURE 5 Force vs. time for haversine and sinusoidal deflection-controlled tests without 2

rest periods (400 microstrains, 21oC) 3

4

Figure 6 illustrates what happens (hypothetically) to the HMA beam during the sinusoidal 5

deflection-controlled test and the haversine deflection-controlled test. In the sinusoidal test 6

(Figure 6 (a)), the deflection input is sinusoidal, which bends the beam in both directions. The 7

neutral position of the beam does not change during the test and remains in the original position 8

half way between the two extreme positions. In the haversine test (Figure 6 (b)), the deflection 9

input is haversine, which bends the beam with the same peak-to-peak mgnitude as the sinusoidal 10

test except in one direction only. Because of the viscous response of the material, creep 11

(permanent deformation) occurs in the beam and the neutral position of the beam shifts dowward 12

after a few loading cycles. The neutral position is located half way between the extreme 13

positions and the haversine deflection is changed to a sinusoidal deflection performed on a bent 14

beam. 15

16



1 2

FIGURE 6 Neutral and extreme positions using sinusoidal and haversine waveform 3

deflection-controlled test on HMA 4

5

Figure 7 illustrates the deflection input and the stress and strain outputs that occur in the 6

HMA beam during the tset. Since the neutral position of the beam does not change in the 7

sinusoidal test, both strain and stress developed are sinusoidal causing alternating tension and 8

compression in the beam as shown in Figure 7 (a). In the haversine test, the deflection input 9

remains haversine throughout the test. The developed strain and stress pulses start as haversine 10

causing strain and stress in one direction (compression at the top of the beam and tension at the 11

bottom without reversal). Because of the shifted posion of the beam, the developed strain and 12

stress pulses immediately change to sinusoidal causing alternating tension and compression with 13

half of the magnitude of the stress applied at the beginning of the test as shown in Figure 7 (b). 14

At the end of the test, when the load is removed, the beam remains in the bent position showing 15

permanenet deformation. This observation also confirms the conclusions of Pronk‟s et. al (1, 2). 16

Note that the strain always lags behind the stress in both the sinusoidal and haversine tests. 17

Currently, the literature incorrectly uses the terms “strain-controlled” and “deflection-18

controlled” for beam fatigue tests on HMA interchangeably. Since the loading machine controls 19

the deflection, not the strain, the so-called haversine strain-controlled test is technically a 20

haversine “deflection-controlled” test. This is esecially important when testing a viscoelastic 21

material such as HMA, since the deflection remains haversine while the strain changes to 22

sinusoidal. If the test is run on an elastic material such as a portland cement concrete, a 23

deflection-controlled test would be the same as a strain-controlled test because the deflection 24

matches the strain. 25

26



1 2

FIGURE 7 Stresses, strains and deflections versus time for sinusoidal and haversine 3

deflection-controlled tests 4 5

Fatigue Tests with Rest Periods 6

In this part of the study, deflection-controlled haversine and sinusoidal flexure fatigue tests were 7

performed with rest periods of either 5 or 10 seconds using the same HMA materials and other 8

conditions as the test without rest period. The shapes of the force and deflection pulses were 9

examined for both haversine and sinusoidal waveforms during the test. Figure 8 shows an 10

example of several cycles of input deflection and the resulting force response during the 11

sinusoidal and haversine tests with rest period. For the sinusoidal test, both the deflection input 12

and resulting force output are sinusoidal. For the haversine test, the force reverses direction at 13

the end of the pulse for a short period of time because of the creep. During the rest period, 14

however, the forces (stresses) are mostly recovered and force (stresses) waveform changes to be 15

close to haversine with a small negative value depending on the duration of the rest period. 16

17



1

Force and Deflection vs. Time (3 consecutive cycles)

(70F, 800 s, 5 sec RP, Strain-Controlled, Sinusoidal)

-1.2

-0.8

-0.4

0

0.4

0.8

1.2

Time

Fo

rce

, k

N

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

De

fle

cti

on

, m

m

Deflection-

Input

Force-

Output

1499.0 1499.1 1504.1 1504.2 1509.2 1509.3

5 Sec. RP 5 Sec. RP 2

(a) Sinusoidal 3

4

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1498.8 1499.1 1499.4 1499.7 1500 1500.3

Time, sec

Fo

rce

, k

N

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

Deflection-

Input

(70F, 800 s, 5 sec RP, Strain Controlled)

Defl

ecti

on

, m

m

Force-

Output

5 (b) Haversine 6

FIGURE 8 Force and deflection vs. time for a deflection controlled test with sinusoidal and 7

haversine pulses with rest periods (800 microstrains, 21oC, 5 sec. rest period) 8

9



Comparing the sinusoidal test without rest period (Figure 4 (a)) to the sinusoidal test with 1

rest period (Figure 8 (a)), the deflection and force (stress) waveforms maintain a sinusoidal 2

pattern. This means that the stress and strain conditions will be the same in both tests with and 3

without rest period. This condition would produce a fair comparison in the fatigue and healing 4

analysis. On the other hand, comparing the haversine test without rest period (Figure 4 (b)) to 5

the haversine test with rest period (Figure 8 (b)) shows that the haversine test does not produce 6

consistent results. The test without rest period produces sinusoidal forces (stresses), whereas the 7

test with rest period produces almost haversine forces (stresses). As discussed earlier, haversine 8

forces result in tension at the bottom of the beam and compression at the top, whereas sinusoidal 9

forces result in reversible tension and compression at the top and bottom of the beam. Also, 10

alternating tensile and compressive stresses are equal to about half of the stress magnitude 11

produced by haversine forces even though both tests run under the same deformation waveform 12

and peak-to-peak value. Moreover, tensile stresses reduce the fatigue life of the beam, while 13

compressive stresses may actually heal micro cracks and prolong the fatigue life of the specimen. 14

This implies that the haversine test with a rest period is more harmful to the beam than 15

the haversine test without rest period. Although the rest period helps in the healing process, the 16

haversine force bends the beam in one direction with almost double the magnitude of the case 17

without rest period. This produces too much tension at the bottom of the beam. Therefore, a 18

totally unfair comparison could result when comparing the tests with and without rest period in 19

the healing analysis as discussed in the next section. 20

Consequences of Using Haversine Waveform 21

As discussed earlier, the use of a haversine deflection-controlled fatigue test without rest period 22

(ASTM D-7460) produces inconsistent waveforms, which might produce erroneous fatigue 23

results. A more serious effect happens during the healing analysis when the results of the test 24

with rest period are compared to those of tests without rest period. Figure 9 shows examples of 25

fatigue test results using haversine deflection control with and without rest periods. Figure 9 (a) 26

shows that the test with a rest period, in some cases, resulted in faster damage (smaller stress 27

ratios) and lower fatigue life than the test without rest period, producing “negative healing.” 28

This, of course, is completely opposite to the main hypothesis of healing, which is based on the 29

premise that it is the rest period that “heals” the damage in the HMA and extends its fatigue life. 30

In other cases, beams subjected to rest periods started in the proper trend, where they had less 31

damage than beams without rest periods. However, these beams failed during the test as shown 32

in Figure 9 (b and c), which is opposite to what is expected. 33

34


Mamlouk, Souliman, and Zeiada 12 Two Rest Period Levels Comparison

(at 400 s, 40F)

0

0.2

0.4

0.6

0.8

1

0 5000 10000 15000 20000 25000 30000

Cycles

Sti

ffn

es

s R

ati

o

Without rest period, 2 replicates

With 10 sec. rest period, 2 replicates

1 (a) 400 microstrains, 4 C 2 Two Rest Period Levels Comparison

(800 s, 70F)

0

0.2

0.4

0.6

0.8

1

0 2000 4000 6000 8000 10000 12000 14000 16000 18000

Cycles

Sti

ffn

es

s R

ati

o



3 (b) 800 microstrains, 21 C 4 Two Rest Period Levels Comparison

(800 s, 100F)

0

0.2

0.4

0.6

0.8

1

1.2

0 5000 10000 15000 20000 25000 30000

Cycles

Sti

ffn

es

s R

ati

o



5 (c) 800 microstrains, 38 C 6

FIGURE 9 Examples of beam fatigue test results using haversine deflection-control with 7

and without rest periods 8



Figure 10 shows examples of fatigue test results using sinusoidal deflection control. 1

Unlike the case of haversine waveforms, the figure shows that there is always less damage for 2

the test with a rest period as compared to the test without a rest period (positive healing). The 3

figure also shows that the test with rest period results in a longer fatigue life than the test without 4

rest period as expected. 5

Sample 94439

(at 800 s, 70F, 0RP)

0

0.2

0.4

0.6

0.8

1

0 5000 10000 15000

Cycles

Sti

ffn

es

s R

ati

o

With 5 sec. rest period

Without rest period

6 (a) 800 microstrains, 21 C 7

8

Two Rest Perod Comparison

(800 ms, 100F, Strain-Controlled, Sinusoidal)

0

0.2

0.4

0.6

0.8

1

1.2

0 5000 10000 15000 20000 25000

Cycles

Sti

ffn

es

s R

ati

o

Without rest period

With 5 sec. rest period

9 (b) 800 microstrains, 38 C 10

11

FIGURE 10 Examples of beam fatigue test results using sinusoidal deflection-control with 12

and without rest periods 13

14



SIMULATION OF FIELD CONDITION 1

In the field, strain signals at the bottom of the asphalt layer may appear to look more like a 2

haversine than sinusoidal when a wheel load passes (17, 18). Therefore, using a haversine 3

waveform in lab tests may initially appear to be more realistic. Based on the results of this study, 4

however, it is hard to simulate the field condition in the lab since the beam fatigue test with a 5

constant haversine deformation waveform will immediately change into a test with a sinusoidal 6

stress waveform. It is also important to note that only the asphalt mixture is tested in the lab 7

without consideration of the bottom foundation layers (base, subbase or subgrade). Hot-mix 8

asphalt is a viscoelastic material and in contrast with the road there is no „elastic‟ foundation 9

support layer in the lab fatigue test to push the specimen back to its original position after the 10

load is removed (2). Since neither the haversine waveform nor the sinusoidal waveform exactly 11

simulates the field condition, it is important to use sinusoidal waveforms to obtain consistent and 12

more accurate fatigue results as discussed in this paper. 13

SUMMARY AND CONCLUSIONS 14

Deflection-controlled haversine and sinusoidal flexure beam fatigue test protocols are defined in 15

ASTM D-7460 and AASHTO T-321, respectively. This study attempts to optimize the test 16

conditions such as waveform type (haversine vs. sinusoidal), incorporating rest periods between 17

loading cycles and the effect of rest period on the healing of the HMA. The following 18

conclusions have been developed. 19

1. In the deflection-controlled haversine test (ASTM D-7460), permanent deformations lead 20

to a new equilibrium neutral position of the beam after only a few cycles due to the 21

viscoelastic character of asphalt. Although the deflection input remains haversine, the 22

resulting stresses and strains follow a sinusoidal waveform, which bends the beam in both 23

directions very similar to a deflection-controlled sinusoidal test. Haversine strain and 24

stress signals cannot be maintained throughout the test. 25

2. The deflection-controlled haversine test produces erroneous fatigue results since the test 26

assumptions do not match the actual test conditions. The test calculations assume tension 27

at the bottom of the beam and compression at the top, while actually alternating tension 28

and compression at the top and bottom of the beam are developed with only half of the 29

stress magnitude. In addition to the incorrect stress magnitude, tension and compression 30

do not have the same effect on fatigue since tension reduces fatigue life and compression 31

may actually enhance the fatigue life of the specimen. 32

3. The deflection-controlled sinusoidal test (AASHTO T-321) is more consistent than the 33

deflection-controlled haversine test (ASTM D-7460) since it produces the intended stress 34

and strain waveform that is anticipated. 35

4. For studies dealing with the healing index and endurance limit of HMA, when tests with 36

and without rest periods are compared, it is even more important to use a deflection-37

controlled sinusoidal test (AASHTO T-321) in order to obtain a fair comparison and 38

accurate fatigue and healing results. 39

5. Since neither the haversine waveform nor the sinusoidal waveform in the lab exactly 40

simulates field conditions, it is important to use a sinusoidal waveform in order to obtain 41

consistent results. 42



6. In the beam fatigue test on a viscoelstic material such as HMA, the loading machine 1

controls the deflection, not the strain. Because of the permanent deformation that occurs 2

in the material, the strain does not match the deflection. Therefore, care should be taken 3

when referring to tests on viscoelastic materials. For example, the so-called haversine 4

"strain-controlled" test on HMA is technically a haversine “deflection-controlled" test. 5

Consideration of all of these conclusions leads the authors to strongly recommend that the 6

American Society of Testing and Materials (ASTM) changes the ASTM D-7460 designation and 7

test procedure to eliminate the deflection-controlled haversine waveform and replace it with the 8

deflection-controlled sinusoidal waveform. This change would ensure consistent and more 9

accurate test procedure. 10

AKNOWLEDGEMENT 11

The paper was prepared as a part of the NCHRP Project 9-44A, which is funded by the National 12

Cooperative Highway Research Program (NCHRP). Dr. Matthew Witczak‟s general overview 13

guidance and valuable input to the manuscript are acknowledged and greatly appreciated. 14

REFERENCES 15

1. Pronk A.C. Comparison of 2 and 4 point fatigue tests and healing in 4 point dynamic bending 16

test based on the dissipated energy concept”, 8th International Conference on Asphalt 17

Pavements, Seattle, Washington, USA, 1997. 18

2. Pronk A.C., “Haversine Fatigue Testing in Controlled Deflection Mode: Is It Possible?” 19

Presented at the Transportation Research Board meeting, 2010. 20

3. Al-Khateeb, G., and Shenoy, A. A Distinctive Fatigue Failure Criterion, Journal of the 21

Association of Asphalt Paving Technologists (AAPT), Vol. 73, 2004, pp. 585-622. 22

4. Al-Khateeb, G., and Shenoy A. A Simple Quantitative Method for Identification of Failure 23

due to Fatigue Damage, International Journal of Damage Mechanics, (IJDM), Vol. 20, 2011, 24

pp. 3-21. 25

5. NCHRP Project 944-A, Validating an Endurance Limit for HMA Pavements: Laboratory 26

Experiment and Algorithm Development, Quarterly Progress Report, Arizona State 27

University, Tempe, Arizona, June, 2010. 28

6. Carpenter, S.H., and Shen, S., Application of the Dissipated Energy Concept in Fatigue 29

Endurance Limit Testing, Journal of Transportation Research Record No. 1929, 30

Transportation Research Board, 2005, pp. 165-173. 31

7. Prowell, B., E. R. Brown, R. M. Anderson, J. S. Daniel, A. K. Swamy, H. Von Quintus, S. 32

Shen, S. H. Carpenter, S. Bhattacharjee, and S. Maghsoodloo. Validating the Fatigue 33

Endurance Limit for Hot Mix Asphalt, Final NCHRP Report 646, NCHRP 9-38 Project, 34

National Cooperative Highway Research Program, Washington, D.C., 2010. 35

8. Castro, M. and Sanchez, J.A., Fatigue and healing of asphalt mixtures: Discriminate analysis 36

of fatigue curves. Journal of Transportation Engineering, ASCE, Vol. 132, No. 2, 2006, pp. 37

168-174. 38



9. Monismith, C L, Secor, K E and Blackmer, W., Asphalt mixture behavior in repeated 1

flexure”, Proceedings of Association of Asphalt Paving Technologists, Vol. 30, 1961, 2

pp.188-222. 3

10. Bonnaure, F., Huibers, A., and Boonders, A. A Laboratory Investigation of the Influence of 4

Rest Periods on the Fatigue Characteristics of Bituminous Mixes. Journal of the Association 5

of Asphalt Paving Technologists, Kansas City, Missouri, Vol.51, 1982, pp.104-128. 6

11. Bazin, P., and Saunier, J. Deformability, Fatigue and Healing Properties of Asphalt Mixes. 7

Proceedings of the 2nd International Conference of Structural Design of Asphalt Pavements, 8

Ann Arbor, Michigan, 1967, pp. 553-569. 9

12. Raithby, K.D. and A.B. Sterling, The Effect of Rest Periods on the Fatigue Performance of 10

Hot-Rolled Asphalt under Reversed Axial Loading, Proceedings. The Association of Asphalt 11

Paving Technologists (AAPT), Vol. 39, 1970, pp. 134-147. 12

13. Kim, Y. R., Little, D. N., and Benson, F., Chemical and Mechanical Evaluation on Healing 13

Mechanism of Asphalt Concrete. Journal of the Association of Asphalt Paving Technologists 14

(AAPT), Vol. 59, 1990, pp. 240-276. 15

14. Jacobs, M. M. J., Crack Growth in Asphaltic Mixes. Ph.D. Thesis, Delft University of 16

Technology, the Netherlands, 1995 17

15. Raithby, K.D. and A.B. Sterling., Some effects of loading history on the fatigue performance 18

of rolled asphalt. Transport and Road Research Laboratory (TRRL), Report No. LR 496, 19

Crowthorne, U.K., 1972. 20

16. Abojaradeh, M. A., “Predictive Fatigue Models for Arizona Asphalt Concrete Mixtures,” A 21

Dissertation presented at Arizona State University, Dec. 2003. 22

17. Al-Qadi, I.L., Yoo, P.J., Elseifi, M.A., and Janajreh, I., Effects of tire configurations on 23

pavement damage, Journal of the Association of Asphalt Paving Technologists (AAPT), Vol. 24

74, 2005, pp. 921–962. 25

18. Priest, A. L., Timm, D. H., Solaimanian, M., Gibson, N., and Marasteanu, M., A full-scale 26

pavement structural study for Mechanistic-Empirical Pavement Design, Journal of the 27

Association of Asphalt Paving Technologists (AAPT), 2005, pp 519-556. 28

19. H.Di Benedetto, Q.Nguyen, C.Sauzéat Nonlinearity, Heating, Fatigue and Thixotropy during 29

Cyclic Loading of Asphalt Mixtures, Road Materials and Pavement Design, VOL 12/1, 2011, 30

pp.129-158. 31

32


OPTIMUM TESTING CONDITIONS TO MEASURE HMA FATIGUE …docs.trb.org/prp/12-1266.pdf · 1 OPTIMUM...

Documents

Transcript of OPTIMUM TESTING CONDITIONS TO MEASURE HMA FATIGUE …docs.trb.org/prp/12-1266.pdf · 1 OPTIMUM...