Constructionand Building

Construction and Building Materials 19 (2005) 147–153MATERIALS

www.elsevier.com/locate/conbuildmat

Properties of gap-aggregate gradation asphalt mixture andpermanent deformation

Der-Hsien Shen a,*, Ming-Feng Kuo a,1, Jia-Chong Du b,2

a Pavement Research Laboratory, Department of Construction Engineering, National Taiwan University

of Science and Technology, No. 43, Sec. 4, Keelung Road, Taipei 10672, Taiwanb Department of Civil Engineering, Tung Nan Institute of Technology, No. 152, Sec. 3, PeiShen Road, ShenKeng, Taipei 22202, Taiwan

Received 27 December 2003; received in revised form 7 May 2004; accepted 9 May 2004

Available online 15 June 2004

Abstract

Aggregate of natural crush stone in hot mix asphalt is applied to gap gradation mixed with the AC-20 binder, in accordance with

Marshall mix design. Laboratory tests were conducted, and the single-factor variance analysis (ANOVA) is employed to estimate

the significance of the gradation mixture properties. Based on permanent deformation tests and analytical results, sieve of 2.36 mm

may be omitted for nominal maximum aggregate size (NMAS) of 12.5 mm, and sieve of 4.75 mm may be omitted for NMAS of 19

mm, in the case of the shortage of aggregate.

� 2004 Elsevier Ltd. All rights reserved.

Keywords: Gap-aggregate gradation; Marshall mix design; Permanent deformation test

1. Introduction

The amount of aggregate in hot mix asphalt (HMA)

consists over 90% of the total volume. Hence, such

properties of aggregate as gradation and size definitely

affect the quality of asphalt mixtures for pavement. Ag-

gregate gradation, which is one of the most important

factors to resist pavement distress, is the distribution ofparticle sizes which is normally expressed in percentage

of the total weight. To pursuit durability, safety, com-

fort, and economy of pavement, several mix-design

methods have been developed in Europe, America and

Japan. These are the Marshall design method, Stone

Mastic Asphalt (SMA), Porous Asphalt, Superpave and

Gyratory Testing Method and so on. These are based on

continuous, gap and open aggregate gradation [1,2].

* Corresponding author. Tel.: +886-2-2737-6573; fax: +886-2-2737-

6606.

E-mail addresses: shendh@mail.ntust.edu.tw (D.-H. Shen), kming-

feng@pie.com.tw (M.-F. Kuo), ctu@mail.tnit.edu.tw (J.-C. Du).1 Tel.: +886-2-2737-0456; fax: +886-2-2737-6606.2 Tel.: +886-2-8662-5921x119; fax: +886-2-2662-9583.

0950-0618/$ - see front matter � 2004 Elsevier Ltd. All rights reserved.

doi:10.1016/j.conbuildmat.2004.05.005

Because over 90% of pavement is constructed by as-

phalt pavement in Taiwan, the problem results from

aggregates shortage. Accordingly, to extend the lifetime

of pavement is the necessary direction of government. In

order to solve the lack of aggregate and improve the

durability and serviceability of pavement, the research

on aggregate gradation and the effect of aggregate size

are on urgent demand in Taiwan. In this study, there-fore, evaluation of the effect of gap-aggregate gradation

(GAG) is conducted. The method used for evaluation is

the Marshall mix design which has been the most widely

applied for designing and controlling hot-mix paving

mixtures in Taiwan.

In general, tested results are compared and analyzed

statistically. The statistics analysis could elucidate the

various effects and relationships of the engineeringproperties. Accordingly, the single factor variance

analysis (ANOVA) has been performed to determine the

significance at a certain confidence limit.

A laboratory test on rutting was performed to eval-

uate the designed properties of compacted GAG of

HMA samples by ANOVA method. Thus, properties

designed by GAG Marshall mix design are investigated.

148 D.-H. Shen et al. / Construction and Building Materials 19 (2005) 147–153

The effect of the omitted sieve sizes of GAG mixtures is

clarified on mix properties by ANOVA. Then, rutting

performance of the optimum GAG mixture is deter-

mined by a laboratory test.

Fig. 1. Laboratory wheel tracking device.

2. Test plan

2.1. Test materials

The sieves and the gradation analysis used for GAG

are in accordance with ASTM C136 and ASTM D3515

[3], respectively. Asphalt cement of AC-20 from a localpetroleum company was used. Lime is applied instead of

filler aggregate passing No. 200 sieve (0.075 mm).

2.2. Marshall mix design

Asphalt mix design was performed through the

Marshall method as specified in ASTM D1559. Eighteen

samples of GAG were prepared by heating and com-pressing, which were mixed with varied asphalt content

in 0.5% increment. The samples were compressed by 75

blows per face with the standard Marshall hammer. The

Marshall stability and flow were determined by the

standard Marshall equipment [4]. The optimum asphalt

content (OAC) was chosen in accordance with National

Asphalt Pavement Association (NAPA) TAS-14 of

America [5]. ANOVA analysis was conducted to deter-mine the effect and the optimum properties of GAG

with HMA mixtures.

2.3. Permanent deformation test

The permanent deformation test, i.e., rutting test, was

performed, employing the wheel-tracking device shown

in Fig. 1 for evaluation of pavement performance [6].Samples, which were mixed with optimum asphalt

contents from Marshall mix design and fabricated by

the rolling machine, were of dimensions 300 mm� 300

mm in cross-sectional area and 50 mm in height. Nor-

mally, the rutting test was performed using 1.12 MPa

wheel load at 60� 1 �C temperature under dry condi-

tion. The rut depth was measured after 100, 200, 400,

800, 1400, 1890 and 2520 cycles.

Table 1

The properties of aggregate

Properties Bulk specific

gravity

Absorption (%)

Coarse Fine

Specificationa – – –

Test aggregate 2.655 2.516 0.6

a Specification for aggregate is given in ASTM D693, AASHTO M283. T

lowing ASTM D4791.

3. Results

Properties of aggregate are shown in Table 1 and

those of asphalt cement of AC-20 are shown in Table 2.Test samples for control were two dense gradations of

nominal maximum aggregate size (NMAS) of 12.5 and

19 mm in accordance with ASTM D3515. Gap grading

is defined as grading in which one or more intermediate-

size fractions are omitted. As a result, the percentage of

retained gap gradation in each sieve is corrected and

re-calculated.

Results of sieve analysis for NMAS of 12.5 mm andNMAS of 19 mm, where the amount of aggregate re-

tained from 9.5 to 0.075 mm sieves and lime are omitted,

are shown in Figs. 2–5. As can be seen, all of GAG

groups are enveloped in the zone of lower and upper

limits, which are prescribed in the specification of

ASTM D3515, excepted for the case that aggregate re-

tained in the sieve size of 9.5 mm is omitted for NMAS

of 19 mm (see Fig. 4). Test results of the Marshall mixdesign with GAG are summarized in Table 3, which

contain unit weights, voids in mineral aggregates

(VMA), voids filled with asphalt (VFA), stability, flow

and OAC. The voids in total mix (VTM) used is 4% of

mixtures in accordance with NAPA TAS-14 [5].

The single-factor tests of ANOVA on the omitted

sieve size are shown in Table 4. In Table 4, the unit

weight, VMA, VFA, stability, flow and OAC of samples

L.A. abrasion (%) Soundness (%) Flat and elongated particles

in coarse aggregate (%)

1:3 1:5

<40 <12 – <15

20.2 9.34 7.56 0.57

he flat and elongated particles in coarse aggregate are determined fol-

Table 2

Asphalt cement properties

Asphalt cement properties AC-20

Specificationa Testing

Penetration (1/100 cm) 60–70 65

Specific gravity (25 �C) – 1.029

Softening point (�C) 40–60 48

Ductility (25 �C) min: 100 100+

Cohesion (60 �C, poise) – 2221

Cohesion (135 �C, poise) – 4.93

Flash point (�C) min: 232 292

Solubility (%) min: 99.5 99.68

Loss on heating (%) max: 1.0 0.18

Penetration, of residue (%) min: 70 77

aASTM D946, D3381.

D.-H. Shen et al. / Construction and Building Materials 19 (2005) 147–153 149

are to be tested whether those of variations affect sig-

nificantly confidence of 95% or not.

Results of the rutting test are presented in Table 5.

The minimum rut depth of 4.13 and 5.64 mm are ob-

served for NMAS of 12.5 mm and that of 19 mm, re-

spectively, at 2520 cycles.

4. Analytical results and discussion

The optimum Marshall design properties of GAG,

which are affected by the omitted sieve size, are usually

selected from the comparison of each value and by

statistics. The test result of ANOVA shows that stability

and flow affect significantly GAG of the Marshall mix

0

20

40

60

80

100

0.01 0.1

Sieve S

Perc

ent P

assi

ng (

%)

control

omitted sieve size 9.5mmomitted sieve size 4.75mm

omitted sieve size 2.36mm

lower limit specified

upper limit specified

Fig. 2. Gradation distribution of NMAS of 12.5 mm

design. However, the values of stability and flow could

be neglected for the analysis if these values are below the

design criteria. In addition, the rut depth over 15 mm is

not be accounted in the permanent deformation test.

4.1. Case of NMAS¼ 12.5 mm

In Table 3, all of stability values are satisfied with the

criteria (bigger than 8.00 kN) and lower than that of the

control condition for NMAS of 12.5 mm. Comparison

on the stability value of all omitted sieve size, the

maximum value of stability occurs in the type of GAG

in the case sieve size of 2.36 mm is omitted. In addition,omitted cases from 2.36 to 0.075 mm sieves except for

0.59 mm are satisfied with flow criteria of the Marshall

mix design. The case of 0.075 mm sieve omitted has a

minimum flow.

4.2. Case of NMAS¼ 19 mm

In Table 3, it is found that the stability is satisfiedwith the Marshall criteria and lower than that of the

control condition for NMAS of 19 mm. Because the

gradation criteria is unsatisfactory, omitted sieve of 9.5

mm is not accounted. The values of flow in the control

condition, omitted cases from 4.75 to 0.075 mm sieves

and lime are met with the criteria, except for the case of

2.36 and 0.297 mm sieves omitted. The case of sieve size

of 0.075 mm omitted has a maximum stability and aminimum flow.

1 10 100

ize (mm)

GAG (omitted sieve size from 9.5 to 2.36 mm).

0

20

40

60

80

100

0.01 0.1 1 10 100

Sieve Size (mm)

Perc

ent P

assi

ng (

%)

controlomitted sieve size 0.59mmomitted sieve size 0.297mmomitted sieve size 0.149mmomitted sieve size 0.075mmomitted limelower limit specifiedupper limit specified

Fig. 3. Gradation distribution of NMAS of 12.5 mm GAG (omitted sieve size from 0.59 to 0.075 mm).

0

20

40

60

80

100

0.01 0.1 1 10 100

Sieve Size (mm)

Perc

ent P

assi

ng (

%)

controlomitted sieve size 9.5mmomitted sieve size 4.75mmomitted sieve size 2.36mmlower limit specifiedupper limit specified

Fig. 4. Gradation distribution of NMAS of 19 mm GAG (omitted sieve size from 9.5 to 2.36 mm).

150 D.-H. Shen et al. / Construction and Building Materials 19 (2005) 147–153

4.3. Permanent deformation test

Results of the average deformation of the samples in

the rutting test at 60� 1 �C are shown in Table 5 and

Fig. 6. For NMAS of 12.5 mm, the case of sieve 2.36

mm omitted has the lowest rut depths, while for the

NMAS of 19 mm, the case of 4.75 mm omitted has the

lowest rut depths.In Fig. 6, the rut depths at 60� 1 �C indicate that the

deformation appears to be plastic flow not consolidation

for omitted sieve size from 0.59 to 0.149 mm due to

higher rut depths regardless as NMAS of 12.5 and

0

20

40

60

80

100

0.01 0.1 1 10 100

Sieve Size (mm)

Perc

ent P

assi

ng (

%)

controlomitted sieve size 0.59momitted sieve size 0.297mmomitted sieve size 0.149mmomitted sieve size 0.075mmomitted limelower limit specifiedupper limit specified

Fig. 5. Gradation distribution of NMAS of 19 mm GAG (omitted sieve size from 0.59 to 0.075 mm).

Table 3

GAG test results by Marshall mix design

Engineering properties Specification Control Omitted sieves

9.5 mm 4.75 mm 2.36 mm 0.59 mm 0.297

mm

0.149

mm

0.075

mm

Lime

NMAS¼ 12.5 mm

Unit weight (kg/m3) – 2368.00 2297.00 2310.00 2320.00 2363.50 2344.00 2362.50 2354.00 2335.50

VMA (%) >14 15.40 16.54 15.85 16.40 14.07 14.55 14.00 14.32 14.87

VFA (%) 65–75 75.00 75.82 75.76 75.61 68.80 76.75 67.80 74.95 69.30

Stability (kN) >8.00 17.80 11.38 12.00 13.42 10.75 12.19 11.31 11.72 10.22

Flow (0.01 cm) 20–36 36.00 45.50 54.00 33.40 41.80 34.55 31.75 28.45 41.20

OAC (%) – 5.60 6.09 6.25 6.10 6.31 5.26 5.39 5.30 5.48

NMAS¼ 19 mm

Unit weight (kg/m3) – 2430.00 2320.00 2355.00 2350.00 2358.00 2339.50 2380.50 2353.50 2349.00

VMA (%) >13 13.10 15.00 15.50 13.80 12.87 13.93 13.05 13.85 14.06

VFA (%) 65–75 69.47 73.33 75.19 71.01 67.80 59.35 69.80 69.90 71.60

Stability (kN) >8.00 18.25 13.25 10.50 10.18 10.58 11.92 11.55 11.93 11.09

Flow (0.01 cm) 20–36 35.00 42.50 32.00 60.00 35.70 37.10 34.60 25.40 33.50

OAC (%) – 4.50 5.50 5.30 5.70 5.21 4.93 5.24 5.26 5.48

D.-H. Shen et al. / Construction and Building Materials 19 (2005) 147–153 151

19 mm. In general, asphalt cement in high temperatures

may lubricate the mix that causes the loss of internal

friction between aggregate particles, and results in loads

being carried by the asphalt cement rather than the ag-gregate structure. Plastic flow can also occur when ag-

gregate lack angularity and surface texture. Due to the

internal friction between aggregate particles the rutting

resistance is provided, and plastic flow can be minimized

by using large-size, angular and rough textured aggre-

gates [1,7]. However, aggregate and asphalt cement used

are the same source in this study. As a result, physical

properties of aggregate such as angular and rough tex-

tured are similar to each other. Therefore, the smaller

rutting observed suggest that these mixes are well-

graded mixtures and, have high internal friction.The phenomenon of rutting (shown in Fig. 6) indi-

cates that internal friction plays a main role in the rut-

ting resistance at high temperature, even though the

mixtures has higher value of stability or lower flow than

others. A sample with high value of stability or low

value of flow may not promise a low rut depth such as

the sieve size of 0.075 mm omitted (shown in Table 3).

Table 4

ANOVA single-factor test for omission sieve sizes of Marshall mix design samples (a ¼ 0:05)

SS df MS F Fcritical p-value

Source of variation (unit weight)

Between 11216.16 9 1246.24 2.2056 3.0204 0.116906

Within 5650.35 10 565.03

Total 16866.51 19

Source of variation (VMA)

Between 12.5337 9 1.39 1.2035 3.0204 0.386128

Within 11.5720 10 1.16

Total 24.1057 19

Source of variation (VFA)

Between 115.02 9 12.78 0.6411 3.0204 0.742062

Within 199.35 10 19.94

Total 314.38 19

Source of variation (stability)

Between 876927.80 9 97436.42 10.4638 3.0204 0.000521

Within 93117.25 10 9311.73

Total 970045.10 19

Source of variation (flow)

Between 1217.60 9 135.2887 4.5577 3.0204 0.01331

Within 296.84 10 29.6839

Total 1514.44 19

Source of variation (OAC)

Between 1.6934 9 0.1882 0.6323 3.0204 0.748586

Within 2.9759 10 0.2976

Total 4.6693 19

Table 5

GAG rutting test results (60 �C, 1.12 MPa)

Cycles Control Omitted sieves

9.5 mm 4.75 mm 2.36 mm 0.59 mm 0.297 mm 0.149 mm 0.075 mm Lime

NMAS¼ 12.5 mm

0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

100 0.27 1.04 1.11 1.27 1.56 2.81 3.43 1.81 1.76

200 0.50 1.20 1.44 1.46 2.25 4.01 4.67 2.10 2.12

400 0.67 1.89 2.00 2.04 4.23 4.10 5.04 2.51 2.39

800 0.87 2.37 2.47 2.59 4.48 5.28 6.43 3.03 3.14

1400 1.20 3.56 3.88 2.99 7.66 6.28 7.89 3.47 4.23

1890 1.33 4.66 4.96 3.61 11.52 8.23 9.91 4.09 5.09

2520 1.60 6.36 7.12 4.13 13.06 9.28 10.26 4.86 5.91

NMAS¼ 19 mm

0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

100 0.39 1.32 0.81 1.16 1.53 3.33 3.73 2.95 2.47

200 0.50 1.59 1.26 1.52 6.32 4.45 4.56 3.46 3.07

400 0.65 2.14 1.76 2.25 7.49 4.75 5.26 3.96 3.57

800 0.83 2.34 2.86 2.74 10.01 7.31 7.57 5.02 4.43

1400 0.93 3.27 3.98 4.11 13.69 9.91 9.61 6.29 6.02

1890 0.93 3.84 4.54 4.81 –a 12.35 11.66 7.30 7.75

2520 1.00 4.50 5.64 6.30 –a 14.94 14.51 8.68 10.23

aRutting depth greater than 15 mm.

152 D.-H. Shen et al. / Construction and Building Materials 19 (2005) 147–153

Thus, the smaller rutting observed of these mixes sug-

gests that sieve of 2.36 mm omitted for NMAS of 12.5

mm and sieve of 4.75 mm omitted for NMAS of 19 mm

are well-graded mixtures and have the highest internal

friction.

5. Conclusions and recommendations

Based on the results of evaluation and analysis,

conclusions and recommendations of this study are de-

scribed as the following:

0

2

4

6

8

10

12

14

0 500 1000 1500 2000 2500 3000

Cycles

Rut

ting

dept

hs (

mm

)

Control9.5mm4.75mm2.36mm0.59mm0.297mm0.149mm0.075mmLime

0

2

4

6

8

10

12

14

16

0 500 1000 1500 2000 2500 3000Cycles

Rut

ting

dept

hs (

mm

)

Control9.5mm4.75mm2.36mm0.59mm0.297mm0.149mm0.075mmLime

(a)

(b)

Fig. 6. Plot of GAG rutting depths. (a) NMAS of 12.5 mm (omitted

sieve size from 9.5 to 0.075 mm), (b) NMAS of 19 mm (omitted sieve

size from 9.5 to 0.075 mm).

D.-H. Shen et al. / Construction and Building Materials 19 (2005) 147–153 153

1. From single-factor tests of ANOVA on the omitted

sieve size, it is clarified that the values of stability and

flow have the significant effect in confidence of 95%.

2. All of stability values are satisfied with the criteria

and lower than that of the control condition.

3. Omitted sieve size of 2.36, 0.297, 0.149 and 0.075 mm

for NMAS of 12.5 mm, and omitted sieve size of 4.75,

0.59, 0.149, 0.075 mm and lime for NMAS of 19 mmare satisfied with the design criteria.

4. The statistical analysis on the single-factor of ANO-

VA shows that the omitted sieve size of 0.075 mm

has the optimum properties of the Marshall mix

design.

5. Based on the analytical results and permanent defor-

mation test, the aggregate used may firstly select the

sieve of 2.36 mm omitted for NMAS of 12.5 mm,and sieve of 4.75 mm omitted for NMAS of 19

mm. The second selection may use sieve of 0.075

mm omitted, if the shortage of aggregate.

References

[1] Roberts FL, Kandhal PS, Brown ER, Lee DY, Kennedy TW.

Hot mix asphalt materials, mixture design and construction.

2nd ed. Maryland: NAPA research and education foundation;

1996.

[2] Association of Japan pavement. Porous pavement technology,

Japan; 1992.

[3] Annual book of ASTM standards. USA; 1995.

[4] The asphalt handbook (MS-4). USA, Asphalt Institute; 1989.

[5] Mix design techniques-part I. NAPA TAS-14, National Asphalt

Pavement Association. Instructors manual; 1982.

[6] Nienelt G, Thamfald H. Evaluation of the resistance to deforma-

tion of different road structures and asphalt mixtures determined

the pavement rutting tester. AAPT 1988:57.

[7] MTC, Ministry of Transportation and Communications.

Highway construction and maintenance manual. Taiwan;

2001.