Rutting evaluation of hydrated lime and SBS modified asphalt mixtures for laboratory and field compacted samples

Construction and Building Materials 25 (2011) 756–765

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Construction and Building Materials

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Rutting evaluation of hydrated lime and SBS modified asphalt mixturesfor laboratory and field compacted samples

Halit Özen *

Yildiz Teknik Üniversitesi, Civil Engineering Department, Istanbul, Turkey

a r t i c l e i n f o a b s t r a c t

Article history:Received 12 April 2010Received in revised form 15 July 2010Accepted 18 July 2010Available online 21 August 2010

Keywords:Asphalt mixturesSBS polymerHydrated limeLCPC testRepeated creep testMoisture conditioningCorrelation

0950-0618/$ - see front matter � 2010 Elsevier Ltd. Adoi:10.1016/j.conbuildmat.2010.07.010

* Corresponding author. Address: Yildiz TechnicaEngineering, Department of Civil Engineering, 34210 E+305 348 1393; fax: +(305) 348 2802.

E-mail address: [email protected]

The purpose of this study is to evaluate permanent deformation for hydrated lime and SBS modifiedasphalt mixtures. Control (C), 2% hydrated lime (2L), 5% SBS polymer mixtures and 2%hydrated lime–5%SBS (2L5SBS) mixtures were prepared. The Laboratoire Central des Ponts et Chaussées (LCPC) wheeltracker, also known as French Rutting Tester were realized with two different stages. Same LCPC slabswere produced. Original LCPC compactors and also field cylinder were used separately. LCPC rutting val-ues were determined with left and right wheel loadings. Also averages were obtained with calculation.Repeated creep tests were used for these mixtures and permanent deformations were plotted for two dif-ferent moisture conditioning that water immersion and freeze and thaw cycles. Diameter samples(100 mm and 150 mm) were studied in repeated creep tests. In the result that LCPC tracking values werecompared with repeated creep tests in terms of sample diameters. LCPC wheel-tracking test results showthat 2L5SBS mixtures reveal utmost performance according to the other mixtures types. Polymer modi-fication increased rutting resistance of lime modified ones. Both original LCPC compactor and field cylin-der compaction showed resemble results. 150 mm samples showed highest correlation (higher thanR2 = 0.80) between LCPC test and repeated creep test for different compaction types and different mois-ture conditionings.

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1. Introduction

Moisture damage and permanent deformation are the primarymodes of distresses in hot-mix asphalt (HMA) pavements. The per-formance of HMA pavements is related to cohesive and adhesivebonding within the asphalt–aggregate system. The loss of cohesion(strength) and stiffness of the asphalt film, and the failure of theadhesive bond between aggregate and asphalt in conjunction withthe degradation or fracture of the aggregate were identified as themain mechanisms of moisture damage in asphalt pavements. Theloss of adhesion is due to water leaking between the asphalt andthe aggregate and stripping away the asphalt film. The loss of cohe-sion is due to the softening of asphalt concrete mastic. Moisturedamaged pavement may be a combined result of these two mech-anisms. Further the moisture damage is a function of several otherfactors like the changes in asphalt binders, decreases in asphaltfilm thickness, changes in aggregate quality, increased widespreaduse of selected design features, and poor quality control. Moisturesusceptibility of hot-mix asphalt (HMA) pavements continues to be

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l University, Faculty of Civilsenler, _Istanbul, Turkey. Tel.:

a major pavement distress. As moisture damage reduces the inter-nal strength of the HMA mix, the stresses generated by traffic loadsincrease significantly and lead to premature rutting, raveling andfatigue cracking of the HMA layer [1]. Additives have been usedfor improving performance of HMA pavements to various dis-tresses (i.e., permanent deformation, moisture damage, and fatigueor low-temperature cracks). There are numbers of different addi-tives available, which can be introduced directly to the asphalt ce-ment (AC) as a binder modifier, or can be added to the mixturewith the aggregate [2].

Hydrated lime has shown multifunctional effects in hot-mix as-phalt (HMA) mixtures. Numerous studies have demonstrated thathydrated lime in asphalt mixtures can reduce pavement rut-depthbecause of its distinct stiffening effects, moisture-associated dam-age by improving the aggregate–asphalt bonding, and long-termoxidative aging potential. Several experimental studies have alsoshown that hydrated lime can reduce asphalt cracking to some ex-tent despite its stiffening effects because the initial microcrackscan be intercepted and deflected by tiny, active lime particles. Be-cause of the latest observations that hydrated lime is an efficientmaterial for improving fatigue cracking resistance as well as rut-ting, which is not a typically observed phenomenon from othermaterials, the effects of hydrated lime as a crack resister have re-mained unsolved questions and have not been fully understood

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in the asphalt pavement community. Moreover, not many studieshave been conducted to investigate the crack-resistant characteris-tics of hydrated lime-treated mixtures with different applicationrates. Since stiffer mixtures are generally more susceptible tocracking, the crack-resistant characteristics of hydrated lime mightbe degraded from certain critical amounts of lime added, whereasthe rut-resistant potential of mixtures can still be enhanced [3].

Polymers, which are the most commonly used additives in bin-der modification, can be classified into four main categories,namely plastics, elastomers, fibres and coatings. To achieve thegoal of improving bitumen properties, a selected polymer shouldcreate a secondary network or new balance system within bitu-mens by molecular interactions or by reacting chemically withthe binder. The formation of a functional modified bitumen systemis based on the fine dispersion of polymer in bitumen for which the

Table 1Engineering properties of the used aggregate.

Properties Test method Value

L.A. Abrasion (%) ASTM C-131 9.6Flakiness (%) BS 812 (Part 105) 14.7Stripping resistance (%) ASTM D-1664 30–35Water absorption (%) ASTM C-127 0.85Soundness in NaSO4 (%) ASTM C-88 4.06Polished stone value BS 812 (Part 114) 0.60Plasticity index for sandy aggregate TS 1900 Non-plastic

Table 2Aggregate specific gravities (g/cm3).

Grain-size fraction Apparent specific gravity Bulk specific gravity

Coarse aggregate 2.894 2.832Fine aggregate 2.889 2.751Filler aggregate 2.910 –Aggregate mixture 2.893 2.803

Table 3The results of tests performed on asphalt cement (AC 60–70).

Properties Test method Unit Value

Specific gravity (25 �C) ASTM D-70 g/cm3 1.019Softening point (�C) ASTM D36-76 �C 52Flash point (Cleveland) ASTM D-92 �C 210Penetration (25 �C) ASTM D-5 0.1 mm 67Ductility (25 �C) ASTM D-113 cm 100+

0

10

20

30

40

50

60

70

80

90

100

0,01 0,10 1,00 10,00 100,00

Sieve Size, mm

Per

cent

age

Pas

sing

, %

Fig. 1. Aggregate distribution on gradation chart.

chemical composition of bitumens is important. Among polymers,the elastomer styrene–butadiene–styrene (SBS) block copolymer isthe most widely used one. It has been identified that styrene–buta-diene–styrene (SBS) triblock copolymer can obviously improve themechanical properties of mixtures such as aging, permanent defor-mation, low temperature cracking, moisture damage resistance,and so on. Researchers have carried out laboratory experiments re-lated to the effects of styrene–butadiene–styrene and lime on themoisture susceptibility of asphalt concrete mixtures. However lim-ited experimental studies have been conducted for evaluating theeffect of usage of SBS and lime together on the water damage ofhot-mix asphalt [1]. For a polymer to be effective in road applica-tions, it should blend with the bitumen and improve its resistance(to rutting, abrasion, cracking, fatigue, stripping, bleeding, aging,etc.) at medium and high temperatures without making the mod-ified bitumen too viscous at mixing temperatures or too brittle atlow temperatures. In other words, it must improve the overall per-formance of the pavement. Many polymers have been used in themodification process but thermoplastic elastomers are enjoyingwide acceptance as road bitumen modifiers [4].

In the laboratory a wheel-tracking device simulates a vehicle toevaluate permanent deformation of the slab by rut depth. Rutdepth is regarded as an appropriate indicator for comparing thesusceptibility of mixtures to permanent deformation. The Wheel-tracking method, however, cannot be used to determine the mod-ulus of the mixture used by thickness design procedures and there-fore the rut depth cannot be used in mechanistic pavementanalysis. Furthermore, the rut depth of a slab is a total deformationwhich includes deformation caused by densification. Densificationis affected by the compression method and the grading of the mix-ture; therefore the rut depth of a slab varies widely from mixtureto mixture [5].

The dynamic creep test is an interesting alternative to thewheel-tracking test for measuring the sensibility for permanentdeformations, but there is some doubt about the ability of the tra-ditional method to be able to work as a functional method of mea-surement and to distinguish between different types of mixes [6].

Table 4Properties of the used hydrated lime (SKK 80-T).

Chemical properties Method Value

Total CaO (%) EN 459-2 85.78Active Ca(OH)2 (%) TS 32 82.04MgO (%) EN 459-2 3.52Total CaO + MgO (%) TS 89.3Loss of ignition (%) EN 459 22.51Insoluble in acid (%) TS 32 1.41R2O3 (%) TS 32 0.47SO3 (%) EN 459 1.47CO2 (%) EN 459 3.89Physical propertiesSandy-over 90 micron EN 459 6Density (kg/m3) EN 459 472

Table 5Summary of Marshall design results.

Design parameters Values Board specification in Turkey

Min. Max.

Bulk specific gravity, Gmb 2.510 – –Marshall stability (kg) 1530 900 –Air voids, Pa (%) 4 3 5Void filled with asphalt, Vf (%) 72 75 85Flow, F, 1/100 in. 3.2 2 4Filler/bitumen 1.17 – 1.5Asphalt cement, Wa 5.15

Fig. 2. Second conditioning system.

Table 6Repeated creep test parameters.

Temperature 40 �CConditioning stress 10 kPaConditioning stress time 1 minConditioning stress rest time 1 minTest stress 100 kPaLoading period 1000 ms (1sn)Time loaded 500 msTime unloaded 500 msPulse number 64800 (18 h)Resting time 15 min

758 H. Özen / Construction and Building Materials 25 (2011) 756–765

LCPC wheel-tracking test and repeated creep test gave similarresults for selected SMA mixtures. In terms of rutting tests it wasthought that repeated creep tests may be a good indicator of

Table 7RCT test deformations for 100 mm diameter samples.

Pulses Freeze–thaw cycled samples (100 mm diameter)

2L5SBS9 2L5SBS10 2L9 2L10 C7 C6

1 83 131 104 212 144 1210 296 327 207 617 385 4750 555 523 292 1118 722 100

100 694 654 330 1387 945 131501 1009 924 500 2052 1649 219

1000 1167 1073 612 2369 2006 2545011 1631 1426 950 2988 2740 328

10000 1844 6411 1137 3239 2982 35319952 2059 6686 3490 3233 37730045 2172 6836 3683 3359 39039810 2200 6902 3761 3466 39850118 2237 6987 3838 3534 40564730 2246 7024 3935 3631 413

Table 8RCT test deformations for 150 mm diameter samples.

Pulses Freeze–thaw cycled samples (150 mm diameter)

C7 C8 C9 2L4 2L5 2L6 2L5SBS4 2L5SBS5 2L5SBS

1 170 54 100 117 144 143 133 162 135501 1790 681 2129 1771 2206 2659 1688 3115 1661

1000 2300 870 2688 2507 2754 3307 2060 3955 19953004 3203 1230 3602 3469 3672 4361 2695 5341 25295011 3644 1437 4001 3766 4095 4856 2988 5966 2783

10000 4256 1735 4521 4215 4661 5487 3378 6750 312919952 4913 2039 5077 4638 5157 6234 3777 7481 348330045 5309 2192 5414 4862 5392 6756 3981 7878 368339810 5570 2300 5613 5042 5563 6963 4123 8130 382850118 5777 2389 5785 5168 5707 7144 4247 8330 393764730 5984 2479 5957 5321 5887 7342 4354 8538 4046

SMA mixtures or else stony skeleton mixes [7]. Unlike this researchcontinuous gradation was offered and the result was that repeatedcreep test and wheel-tracking test did not give parallel result. Theevaluation of the dynamic creep test showed that the test can beused as an indicator of potential rutting, but the results in thesecases should be confirmed with other more reliable tests. Also itis thought that gradation changing is more important than com-pacting effecting types in view of evaluating efficiency of ruttingtest methods [8].

Pavements built lime-treated bitumen should have relativelygreater resistance to rutting at the temperatures and also greaterresistance to transverse thermally induced cracking at low temper-atures. Based on the data at these two temperature extremes, it istempting to speculate that, at some intermediate temperature, forexample 25 �C, asphalt concrete mixtures containing the lime-trea-ted bitumen should have superior resistance to failure during re-peated load during fatigue testing and increased resistance tofatigue cracking in pavements [9].

Water immersed samples (100 mm diameter)

C2 C3 2L6 2L7 2L5SBS9 2L5SBS8

4 340 299 278 226 503 7914 1279 1169 773 705 1305 22125 2479 2577 1334 1184 2025 33798 3024 3364 1614 1428 2344 37844 4178 5015 2262 1992 3019 44158 4596 5523 2543 2236 3282 46226 5423 6304 3144 2734 3847 50556 5774 6556 3378 2969 4064 52245 6088 6753 3613 3204 4281 53750 6297 6940 3754 3336 4366 54596 6440 7071 3866 3439 4432 55063 6573 7202 3932 3524 4508 55630 6716 7333 4044 3599 4564 5619

Water immersed samples (150 mm diameter)

6 C1 C2 C3 2L1 2L2 2L3 2L5SBS1 2L5SBS2 2L5SBS3

135 163 118 163 375 100 152 244 1352138 3031 1548 1686 5852 2475 1640 3407 16382626 3648 2039 2101 6812 3103 2070 3994 20233424 4700 2904 2918 8425 4180 2877 4924 26243789 5217 3250 3300 9192 4754 3280 5348 29304354 6079 3760 4145 10219 5420 3862 5854 33054874 6787 4197 4917 11235 6023 4409 6440 36435120 7223 4415 5353 11777 6311 4732 6712 38855357 7513 4615 5570 12136 6482 4938 6947 40905521 7713 4716 5697 12412 6599 5099 7056 41625712 7967 4734 6123 12689 6735 5243 7138 4180


The purpose of this research is to study rutting of lime and SBSpolymer modified asphalt mixtures. In this context LCPC wheel-tracking tests were realized with both original LCPC compactorand field road cylinder prepared samples. Repeated creep testswere done. Different moisture conditionings were applied. Correla-tion between 100 mm and 150 mm diameter samples and LCPCtests was investigated.

Fig. 3. LCPC wheel tracking values for LCPC compacter (left wheel).

Fig. 4. LCPC wheel tracking values for field roller compacter (left wheel).

Fig. 5. LCPC wheel tracking values for LCPC compacter (right wheel).

2. Materials

Used materials and experimental procedures in this study were following.Aggregate combination and asphalt cement were used. Aggregate combinationwas obtained from the Sularbasi rock quarry. Various engineering properties ofcoarse and fine aggregate were given in Tables 1 and 2.

Regional factors were observed and 60–70 penetration asphalt cement pro-duced from Kirikkale Oil Refinery was used. Test results for asphalt cement areincorporated in Table 3. Gradation curve are represented in Fig. 1.

Hydrated lime (HL) was selected as a modifying agent. HL was added to themixture as a part of filler material. Properties of the used HL were illustrated in Ta-ble 4. Hydrated lime filler was used as 2%. Filler was replaced with the lime.

Fig. 6. LCPC wheel tracking values for field roller compacter (right wheel).

Fig. 7. LCPC wheel tracking values for LCPC compacter (averages).

Fig. 8. LCPC wheel tracking values for field roller compacter (averages).


SBS polymer (Kraton D 1101) was incorporated directly to the bituminous bin-der. Modification was realized in laboratory. 60–70 penetration bitumen washeated to a temperature 180 �C before SBS powder was added. The blend mixturewas mixed at a low speed during 10 min because of homogeneous mix. Mixturewas stirred up vigorously for about 30 min using laboratory mixer after additiveblending operation. Kraton D polymers are elastic and flexible. The inclusion ofbutadiene or isoprene influences the properties of the end product.

Marshall method (ASTM D1559) was used for determining optimal bitumencontent for conventional and modified asphalt mixtures. Three identical sampleswere produced for all alternatives. Bitumen range region was regulated accordingto the bitumen demand for each mixture and asphalt briquettes were fabricated.Compacting energy was applied as 50 blows. The results of Marshall test are pre-sented in Table 5.

Cylindrically produced samples were researched in view of permanent defor-mation. For this purpose damage mechanisms were applied to half of the samplestwo different moisture conditioning system were applied. In the first conditioningconditioned samples were kept in 50 �C water for 48 h and after 48 h in the roomtemperature. This process was repeated as three stages. In the second system sam-ples were located in �15 �C freezer for 72 h. Plastic bags were used. After 72 h sam-ples were waited in room temperature for 24 h. These processes were also repeatedas three steps. Fig. 2 shows a section from the second conditioning.

Control, 2%lime and 2%lime–5%SBS polymer mixtures were produced. Perfor-mance tests were realized with these unconditioned and conditioned samples.

3. Permanent deformation tests

LCPC wheel-tracking tests both original LCPC compactor andfield rollers were applied. Repeated creep tests were researchedwith two different conditioning. Lime, SBS polymer and lime–SBS

Table 9LCPC rutting values for original LCPC compacted control samples.

Left sample Dp = 2515

Cycle 1000 1000 3000 5000 10,000 30,000 50,000Value N/�C 24 �C 60 �C 60 �C 60 �C 60 �C 60 �C 60 �C

A1 7.59 8.78 9.36 9.40 9.45 10.68 10.96A2 7.73 9.59 9.84 9.90 10.61 11.55 12.12A3 6.97 8.57 8.65 9.61 9.66 10.20 10.77B1 9.75 11.18 11.48 11.58 11.98 13.18 13.68B2 9.68 11.74 12.10 12.50 12.97 14.13 14.83B3 9.49 11.13 11.70 11.74 12.49 13.43 13.83C1 10.40 12.17 12.26 12.30 12.93 13.77 14.23C2 10.00 12.39 12.79 13.14 13.60 14.76 15.32C3 9.14 11.03 11.97 12.29 12.66 13.58 14.21D1 8.74 9.76 10.30 10.60 10.64 11.85 12.22D2 10.45 12.66 13.16 13.57 13.60 15.11 15.69D3 10.74 12.60 12.97 13.36 13.82 14.56 15.17E1 7.77 9.12 9.57 9.63 9.75 10.52 11.08E2 8.94 10.97 11.51 11.76 11.98 13.17 13.41E3 8.85 10.49 10.89 11.11 11.34 12.20 12.68

AVRG = 9.08 10.81 11.24 11.50 11.83 12.85 13.35%Rut = – 1.73 2.15 2.42 2.75 3.76 4.26

Right sample Dp = 2505

E3 11.44 13.14 13.54 13.56 14.26 15.78 16.61E2 9.68 12.40 13.07 13.95 14.50 16.36 17.54E1 10.53 12.53 12.83 12.86 13.56 15.26 16.08D3 11.80 13.59 13.70 14.44 14.66 16.87 17.48D2 10.34 13.35 14.11 14.67 15.40 17.90 18.80D1 11.27 14.00 14.69 15.24 15.67 18.14 18.76C3 11.31 13.05 13.69 13.75 14.54 16.05 17.49C2 11.46 14.16 14.75 15.15 15.77 17.85 18.20C1 10.84 12.90 13.28 13.70 13.93 15.53 16.41B3 11.17 12.78 13.12 13.38 13.91 15.86 16.83B2 9.94 12.59 13.27 13.63 14.37 16.45 16.90B1 9.63 11.22 12.39 12.64 13.32 15.19 15.84A3 7.08 10.38 10.64 10.83 10.98 12.36 13.31A2 4.71 6.56 7.19 7.32 8.42 9.84 10.46A1 7.77 9.17 9.66 9.78 10.36 11.53 12.40AVRG = 9.93 12.12 12.66 12.99 13.58 15.40 16.21%Rut = – 2.19 2.73 3.06 3.65 5.47 6.28

CYCLE = 1000 1000 3000 5000 10,000 30,000 50,000AVRG%RUT = – 1.96 2.44 2.74 3.20 4.62 5.27

modified mixtures were interrogated and correlation betweenthese tests were studied for different sample diameters (100 mmand 150 mm samples).

3.1. Repeated creep tests

The implementation of a suitable test for assessing resistance toaccumulated permanent deformation under repeated loading,which leads to wheel track rutting, is probably the most importantrequirement for performance-based specifications. This is becausea wide range of mixture parameters, not least those associatedwith the aggregate, affects it. By contrast, elastic stiffness and fati-gue are principally controlled by the binder characteristics and vol-umetric proportions of the mixture and can be estimated on thebasis of past research for conventional materials. It was for thesereasons that the uniaxial static creep test was introduced in the1970s. It is now recognized that repeated loading is a necessaryrequirement; hence the repeated load axial test was developed atNottingham. This was done originally very much in the contextof mixture design [10].

Cylindrical samples of the HMA were subjected to repeated loadcreep test in Universal Materials Testing Apparatus (UMATTA) pro-cess (NAT tester). Unconfined repeated load uniaxial creep testwere realized with selected test parameters illustrated in Table 6.

Repeated creep tests were realized with conventional and mod-ified asphalt mixtures. Both HL and SBS polymer modification were

Table 10LCPC rutting values for original LCPC compacted 2%lime modified samples.



A1 9.48 10.41 11.58 11.80 11.95 12.58 12.68A2 9.68 10.76 11.85 12.36 12.38 12.98 13.49A3 9.92 10.96 11.47 11.68 12.06 12.65 13.03B1 8.99 10.22 10.64 10.82 11.19 12.00 12.79B2 9.68 11.25 11.94 12.31 12.72 13.65 13.99B3 10.29 11.54 12.18 12.22 12.70 13.48 13.76C1 8.38 9.86 10.17 10.43 11.09 11.42 11.75C2 8.61 10.35 11.19 11.50 12.35 12.76 13.27C3 8.10 9.66 10.29 10.75 11.56 11.59 12.14D1 5.76 7.39 8.10 8.38 8.89 9.79 9.97D2 6.34 8.42 8.88 9.00 9.21 10.08 10.35D3 6.92 8.30 8.79 9.18 9.55 10.30 10.61E1 4.58 6.40 6.90 7.17 7.47 8.06 8.73E2 4.16 5.36 6.25 6.60 6.80 7.39 7.48E3 5.98 7.43 7.78 8.31 8.40 9.20 9.52

AVRG = 7.79 9.22 9.87 10.17 10.55 11.20 11.57%Rut = – 1.43 2.08 2.38 2.76 3.40 3.78



CYCLE = 1000 1000 3000 5000 10,000 30,000 50,000AVRG%RUT = – 1.51 2.28 2.58 3.05 3.91 4.43


applied. In aggregate blending filler content was 6.0% of total gra-dation (C-conventional control). Filler content was decreased 2%.HL was used as 2% of total filler (6%) contents. 2% lime (2L), 2%lime–5%SBS (2L5SBS) polymer synergistic mixtures were pro-duced. Two identical samples for 100 mm diameter samples andthree identical samples for 150 mm samples were used. Environ-mental conditioning systems were introduced interested samples.In repeated creep tests duration two replicate samples were usedfor each mixtures and samples were produced carefully. For somepulse time’s creep values were presented in Tables 7 and 8.

Identical samples were prepared with great care because ofangularity effects of used rock combination. Although, generally,wheel-tracking tests appear to be well correlated with rutting inthe field, there are at present no quantified relationships to linkwheel-tracking test results to rutting in the field under variabletraffic loading and environmental conditions. For this reason,wheel-tracking tests cannot as yet be used to provide a quantita-tive estimate of rutting in the field. The test does, however, providea reliable estimate of the rutting potential and, hence, can be usedto rank mixes according to rut potential. Wheel-tracking tests areparticularly recommended for the evaluation of rutting perfor-mance of stone–skeleton mixes, or mixes that include modifiedbinders. Experience has shown that these mix types cannot beproperly evaluated by means of conventional tests such as theunconfined uniaxial static or dynamic creep tests [8].

Although different polymer modifiers were used such as elasto-meric or plastomeric polymers, drainage inhibitors, mostly higher-

Table 11LCPC rutting values for original LCPC compacted 5%SBS modified samples.



A1 3.75 4.83 5.28 5.98 6.13 6.70 7.52A2 6.11 7.85 8.60 8.71 8.95 9.98 10.06A3 7.21 8.16 8.53 8.79 9.13 9.48 9.58B1 6.33 7.26 7.53 7.62 8.02 8.41 8.51B2 7.03 8.33 9.18 9.24 9.65 10.22 10.27B3 6.18 7.60 8.10 8.30 8.49 9.24 9.35C1 5.93 7.14 7.19 7.26 7.44 7.84 8.04C2 6.59 8.03 8.58 8.89 8.91 9.14 9.50C3 7.59 8.54 8.60 8.80 9.50 10.08 10.08D1 4.84 6.27 6.39 6.64 6.92 7.57 7.79D2 4.96 6.85 7.13 7.89 8.24 9.11 9.54D3 7.17 8.38 8.81 8.87 8.94 9.33 10.04E1 4.84 6.32 6.70 6.81 7.19 7.77 7.82E2 5.24 6.71 7.35 7.42 7.94 8.67 8.71E3 6.29 7.43 7.81 7.86 8.46 9.12 9.20ORTL = 6.00 7.31 7.72 7.94 8.26 8.84 9.07

%T_IO = – 1.31 1.71 1.93 2.26 2.84 3.06


E3 8.46 9.09 9.18 9.54 9.68 10.13 10.21E2 6.07 6.38 6.43 6.49 6.95 7.40 7.44E1 6.43 7.82 7.90 7.95 8.21 8.59 8.73D3 8.19 8.99 9.00 9.07 9.25 10.58 10.65D2 7.43 8.72 9.10 9.25 9.53 9.95 9.98D1 7.46 8.60 8.69 8.71 9.23 9.69 9.74C3 8.04 8.94 9.18 9.24 9.44 9.79 9.81C2 6.38 7.70 8.15 8.55 8.79 8.88 8.94C1 8.42 9.65 9.72 9.90 9.98 10.00 10.34B3 5.65 6.63 7.10 7.38 7.51 7.86 7.95B2 3.75 5.64 6.34 6.38 6.92 7.04 7.10B1 6.09 8.34 8.53 8.77 8.84 9.26 9.27A3 5.57 6.50 6.80 7.00 7.12 7.44 7.47A2 4.12 5.56 5.72 6.37 6.45 7.26 7.35A1 2.58 3.79 5.05 5.92 6.25 9.21 9.22

ORTL = 6.31 7.49 7.79 8.03 8.28 8.87 8.95

DEV_IR = 1000 1000 3000 5000 10,000 30,000 50,000

ORT%TIO = – 1.25 1.60 1.83 2.11 2.70 2.85

performance levels were observed in all tests [8]. Repeated creeptests on Marshall Samples may be used for explaining permanentdeformation [10].

3.2. LCPC wheel-tracking tests

Rutting test was verified with the LCPC method. This test hasbeen used in France for over 20 years to successfully prevent rut-ting in HMA pavements. In recent years, the test has been usedin the United States. This test is capable of simultaneously testingtwo HMA slabs. Slab dimensions are typically 180 mm wide,500 mm long, and 20–100 mm thick. Research indicates good cor-relation between LCPC test results and actual field performance[11,12].

Samples were prepared at 500 mm length, 180 mm width,100 mm height. Test temperature was 60 �C. Samples were keptat least 12 h at this temperature. Each tire was applied 5000 Nload. Tire pressure was 0.6 MPa (87 psi). Samples must be com-pacted as a determined degree of compacting. Test briquettes werecompacted at 98% field compacting scale. Before the temperaturewas reached at 60 �C, precompacting (1000 cycles) was made.Pre-conditioning temperature was regulated and values weresaved. After the values were saved rutting was calculated withY = A � (N/1000)B where A: rutting for 1000 cycle, N: cycle number,B: tangent of linear line in logarithm coordinates. Two identicalsamples were used for each alternative. LCPC rutting test results

Table 12LCPC rutting values for original LCPC compacted 2%lime 5%SBS samples.



A1 5.25 5.82 6.00 6.14 6.20 6.38 6.47A2 4.66 5.06 5.55 5.68 5.69 5.85 5.88A3 4.92 5.14 5.25 5.66 5.93 6.15 6.18B1 4.42 5.04 5.25 5.30 5.41 5.80 6.09B2 4.47 5.96 6.49 6.53 6.83 7.29 7.85B3 7.11 7.95 8.35 8.50 8.57 9.02 9.03C1 7.40 7.48 7.56 7.89 8.10 8.18 8.37C2 7.94 8.66 8.94 9.01 9.20 9.45 9.69C3 7.41 8.36 8.59 8.76 8.90 9.34 9.50D1 5.50 6.20 6.27 6.37 6.60 6.71 7.08D2 6.75 7.65 8.21 8.25 8.34 8.42 8.59D3 6.59 7.14 7.56 7.60 7.65 7.82 7.91E1 4.50 5.16 5.39 5.55 5.73 5.92 6.07E2 6.83 7.77 7.99 8.13 8.31 8.51 8.68E3 4.32 5.22 5.52 5.73 5.75 5.89 6.25AVRG = 5.87 6.57 6.86 7.01 7.15 7.38 7.58%Rut = – 0.70 0.99 1.14 1.28 1.51 1.70



CYCLE = 1000 1000 3000 5000 10,000 30,000 50,000AVRG%RUT

=– 0.94 1.28 1.44 1.61 1.86 2.06


for conventional and modified mixtures are shown in Figs. 3–8.Conventional mixtures show the highest permanent deformationin this test for all compaction types.

For the laboratory mixes, it was the intention to assess mostHMA mix types currently used in South Africa. These included bothstone–skeleton mixes (stone–mastic asphalt and semi-open as-phalt with bitumen–rubber binder) and sand-skeleton mixes(gap- and continuously graded asphalt). Porous asphalt was not in-cluded. The Transportek wheel-tracking test gave reasonable re-sults, and is recommended for all high reliability projects. Thetest is appropriate for all mix types, including mixes containingmodified binders and stone–skeleton mixes. For Stone–skeletonmixes, the test must be performed at the refusal air void contentotherwise the mix could deform excessively, which is not expectedif the mix is well compacted in the field provided that it is designedcorrectly. Because the dynamic creep does not correctly determinethe rutting resistance of all mixes, and the performance ratings donot agree with the Transportek wheel-tracking test, the dynamiccreep test is not recommended for assessing the rutting potentialof HMA other than sand-skeleton mixes manufactured withunmodified binders, unless evaluated in conjunction with otherrutting tests. The evaluation of the dynamic creep test showed thatthe test can be used as an indicator of potential rutting, but the re-sults in these cases should be confirmed with other more reliabletests [8].

Table 13LCPC rutting values for field roller compacted control samples.






CYCLE = 1000 1000 3000 5000 10,000 30,000 50,000AVRG%RUT

=– 3.18 4.21 4.91 5.76 6.96 7.47

The usual testing methods (Marshall test, wheel-tracking test,repeated load uniaxial test) are inadequate for the characterizationof the resistance to the permanent deformation of asphalt. This isnot to say that these tests would be unsuitable for other applica-tions, for example, in a mixture design procedure within givencomposition limits. However, reliable comparisons of the deforma-tion behavior of various sorts of mixtures are not possible on thebasis of these tests [13]. The efficiency of SBS polymer additivewas clearly observed at high temperature (40 �C) for both staticand repeated creep tests. The pre-modified (PM) mixtures showedslightly increased resistance to the permanent deformation thanthe laboratory-modified (M) mixtures. The static creep test wasfound to be a good indicator of the permanent deformation resis-tance at high temperature (40 �C) for conventional and modifiedmixtures. The repeated creep test was shown to be a good indicatorof rutting and the superior performance of polymer-modified mix-tures in terms of rutting was clarified for the dense skeleton. It wasclearly observed that at the higher temperature (40 �C) all conven-tional samples disintegrated and cracking planes were obtained;however, the modified samples retained their structural integrity.The modification with SBS was very effective in increasing the rut-ting resistance of a mixture. A rut depth reduction of 25% was ob-tained with modified mixtures at high temperature at the end ofstatic creep test duration. When the modified mixtures measuredat 40 �C showed higher resistance to rutting by factors of between

Table 14LCPC rutting values for field roller compacted 2%lime modified samples.






CYCLE = 1000 1000 3000 5000 10,000 30,000 50,000AVRG%RUT

=– 2.42 2.89 3.15 3.47 3.92 4.26


6 and 10 in comparison with the conventional ones at the end ofrepeated creep duration [14]. Tables 11–17 gives LCPC wheel-tracking test results for both original LCPC compactor and fieldroller. Tables 9–15 shows LCPC wheel-tracking test results for fieldroller compacted samples.

LCPC rutting tests showed parallel results in view of the differ-ent compaction types as it shown in Figs. 3–8. Left and right wheelsin tests and averages of two showed harmonious results. Lime andSBS polymer modified asphalt mixtures showed highest perfor-mance to the rutting according to the lime modified and controlmixtures. It was shown that LCPC compactor shows good correla-tion with the real field roller. Field roller compacted samplesshowed higher permanent deformation than the LCPC compactor.It is thought that higher void contents can be concerned in high-way pavements. Laboratory prepared samples for both compactedcylindrically samples (Marshall Compaction) and slabs (wheeltracking compactors) gives higher rut resistance because of thecompaction simulation differences.

The results of five testing programs were presented. For the firstprogram, a motorway from Austria was used. Cores were extractedfrom the motorway and recombined into beams for testing. The se-lected motorway was one of the most heavily trafficked in Austriaand had rut depths of 3 mm after 16 months. Results of FRT (LCPC)testing indicated that rutting was 6% after 30,000 cycles. This wasless than the typically recommended 10% maximum for highly

Table 15LCPC rutting values for real field cylinder compacted 2%lime 5%SBS samples.






CYCLE = 1000 1000 3000 5000 10,000 30,000 50,000AVRG%RUT

=– 2.06 2.47 2.63 2.85 3.06 3.17

trafficked roadways. Therefore, concluded that for the Austrianmotorway, the FRT (LCPC) accurately predicted that the HMAstructure would resist deformation [15]. The assessment of theresistance towards rutting is carried out by considering the ratiobetween the depth rut after 30,000 cycles at a temperature of60 �C and the total thickness of the sample before testing. For suchkind of mixture like EME, maximum rutting considering the Frenchstandards (LCPC) is 8%, and it is suggested 5% for heavy traffic [16].In this research 30000 cycles rutting was evaluated. Original LCPCcompacted average rutting ratios (%) for 30000 cycles were foundas control: 4,62, 2%lime: 3,91, 5%SBS: 2,70 and 2%lime–5%SBS:1,86. In addition to this field roller LCPC ratios were calculated asaverages in 30000 cycles. This ratios are control: 6,96, 2%lime:3,92 and 2%lime–5%SBS: 3,06. All mixtures passed acceptance cri-teria. 2L5SBS mixtures showed doubled performance according tothe 2L mixtures for LCPC original compacting.

Repeated creep test results for 100 mm and 150 mm diametersamples were compared with LCPC tests for two different compac-tion efforts. Correlation coefficients were presented in Figs. 9–12.

Regression analysis between repeated creep tests and LCPCwheel-tracking tests in terms of 100 mm and 150 mm diametersamples were studied. Figs. 9–12 compare correlation betweenLCPC field roller and 100 mm–150 mm samples. Higher correlationwas obtained with the 150 mm samples. Enlarging the sample to adiameter of 150 mm while the platen is kept at normal size, i.e.,

Table 16LCPC rutting values for field roller compacted 2%lime modified samples.






CYCLE = 1000 1000 3000 5000 10,000 30,000 50,000AVRG%RUT

=– 2.42 2.89 3.15 3.47 3.92 4.26

Table 17LCPC rutting values for real field cylinder compacted 2%lime 5%SBS samples.






CYCLE = 1000 1000 3000 5000 10,000 30,000 50,000AVRG%RUT

=– 2.06 2.47 2.63 2.85 3.06 3.17

R2 = 0,7758

0

1000

2000

3000

4000

5000

LCPC field roller

100m

m c

reep

def

.

0 2 4 6 8

Fig. 9. Correlation between LCPC field roller and 100 m

R2 = 0,5983

0

2000

4000

6000

8000

LCPC field roller

100m

m c

reep

def

.

0 2 4 6 8

Fig. 10. Correlation between LCPC field roller and 100 m


100 mm, accomplishes a limited lateral pressure, which gives morejustice to mixes that get their stability not so much by forces ofcohesion but much more so by the inner friction of the aggregate.Trials have shown a much better coefficient of correlation (0.91)with the wheel-tracking test for the modified model (diameter ofsample 150 mm and diameter of platen 100 mm) than for the tra-ditional model (0.36) with the same diameter for sample and pla-ten. By evaluating asphalt mixes and pavements from a functionalpoint of view, the possibility to develop better products that betterstand up to demands of today and tomorrow will increase. To beable to use demands on functional properties there is however anecessity for functional methods of measurement that fulfill de-mands on good relevance, high flexibility, and low cost. The firststep in the development of functional methods of measurementis to have for certainty samples with a good affinity to real condi-tions on the road. A study made in Sweden has proven that the tra-ditional Marshall method is not suitable in this regard. Theunsuitability of the Marshall method of compaction has also beenproven by several other investigators in other countries. A studyfor alternatives has emphasized the importance of a kneadingingredient in the compaction effort, which is in accordance withmethods like rolling wheel and gyratory compactor. The samestudy showed that a sample compacted in the laboratory, at thesame degree of compaction, usually gets better mechanical proper-ties (indirect tensile stiffness modulus, dynamic creep test, andindirect tensile test) than a sample compacted in the field and thatthe difference between laboratory and field is not the same for dif-ferent types of mixes [6].

The failure of the Marshall test to describe rutting resistance ofasphalt mixes is demonstrated where the Marshall stability is plot-ted versus the rut depth at 50,000 wheels passes as determined ina laboratory test track experiment. Several conventional and poly-mer-modified binders were used in the experiments. From theseresults it is clear that no relation exists between the Marshall sta-bility and rutting under actual wheel loading in the LTT. The Mar-shall test should therefore not be considered relevant tocharacterize the resistance of mixes with polymer-modified bind-ers. Fortunately, this fact has nowadays been recognized byauthorities who aim to implement rational performance-based

R2 = 0,9207

0

2000

4000

6000

8000

0 2 4 6 8

LCPC field roller

150m

m c

reep

def

.

m and 150 mm samples (freeze and thaw cycling).

R2 = 0,8836

0

2000

4000

6000

8000

0 2 4 6 8

LCPC field roller

150m

m c

reep

def

.

m and 150 mm samples (water immersed samples).

R2 = 0,9176

0

1000

2000

3000

4000

5000

LCPC compactor

100m

m c

reep

def

.

R2 = 0,805

01000200030004000500060007000

0 1 2 3 4 5 6 0 1 2 3 4 5 6

LCPC compactor

150m

m c

reep

def

.

Fig. 11. Correlation between LCPC compactor and 100 mm and 150 mm samples (freeze and thaw cycling).

R2 = 0,0529

0

2000

4000

6000

8000

LCPC compactor

100m

m c

reep

def

.

R2 = 0,8017

0

2000

4000

6000

8000

0 1 2 3 4 5 6 0 1 2 3 4 5 6

LCPC compactor

150m

m c

reep

def

.Fig. 12. Correlation between LCPC compactor and 100 mm and 150 mm samples (water immersed).


specifications in the SHRP in the USA and in Europe in CEN speci-fications [17].

4. Conclusions

SBS polymer and lime–SBS modified asphalt mixtures wereevaluated in a view of rutting performance. LCPC wheel trackingcompaction effort was interrogated with the field roller compac-tion in LCPC loading system. And also 100 mm and 150 mm sam-ples were prepared and repeated creep tests for these sampleswere realized. Regression interaction between different samplesdimensions and LCPC tests were researched. From these researchesit can be concluded:

LCPC wheel-tracking test results show that lime–SBS mixturesreveal highest performance according to the other mixturestypes. Polymer modification increased rutting resistance of limemodified ones.Both original LCPC compactor and field roller compactionshowed resemble results. 150 mm samples showed highest cor-relation (higher than R2 = 0.80) between LCPC test and repeatedcreep test for different compaction types and different moistureconditionings.It was shown that LCPC compactor shows good correlation withthe real field roller. Field roller compacted samples showedhigher permanent deformation than the LCPC compactor. It isthought that higher void contents can be concerned in highwaypavements. Laboratory prepared samples for both compactedcylindrically samples (Marshall Compaction) and slabs (wheeltracking compactors) gives higher rut resistance because ofthe compaction simulation differences.

Acknowledgments

This investigation is a part of the research supported by TUBI-TAK (Project Number: 106M495). The author would like to thankTUBITAK for providing the opportunity to perform this study. Do-gus Construction, Ozture Lime, Isfalt Co is also gratefully acknowl-edged for their laboratory facilities and opportunities. The author isalso indebted to Mr. A. Aksoy for assistance.

References

[1] Kok BV. The effects of using lime and styrene–butadiene–styrene on moisturesensitivity resistance of hot mix asphalt. Constr Build Mater2009;23:1999–2006.

[2] Roque R, Birgisson B, Drakos C, Sholar G. Guidelines for use of modifiedbinders. Florida Department of Transportation, Project number: 4910-4504-964-12; 2005.

[3] Aragoa FTS, Lee J, Kim YR, Karki P. Material-specific effects of hydrated lime onthe properties and performance behavior of asphalt mixtures and asphalticpavements. Constr Build Mater 2010;24:538–44.

[4] Bonemazzi F, Braga V, Corrieri R, Giavarini C, Sartori F. Characteristics ofpolymers and polymer-modified binders. Transportation Research Record1535. Washington (DC): Transportation Research Board; 1996. p. 36–47.

[5] Gui-Ping H, Wing-Gun W. Laboratory study on permanent deformation offoamed asphalt mix incorporating reclaimed asphalt pavement materials.Constr Build Mater 2007;21:1809–19.

[6] Ulmgren N. Functional testing of asphalt mixes for permanent deformation bydynamic creep test modification of method and round robin test. In:Proceedings of the Eurasphalt & Eurobitume Congress; 1996.

[7] Ozen H, Aksoy A, Tayfur S, Celik F. Laboratory performance comparison of theelastomer modified asphalt mixtures. Build Environ 2008;43(7):1270–7.

[8] Tayfur S, Ozen H, Aksoy A. Investigation of rutting performance of asphaltmixtures containing polymer modifiers. Constr Build Mater 2007;21:328–37.

[9] Little DN, Petersen JC. Unique effects of hydrated lime filler on theperformance-related properties of asphalt cements: physical and chemicalinteractions revisited. J Mater Civil Eng 2005:207–18.

[10] Brown SF. Practical test procedures for mechanical properties of bituminousmaterials. Proc Inst Civil Engr, Trans 1995;111:289–97.

[11] Visser AT, Long F, Verhaeghe A, Taute A. Provisional validation of the newSouth African hot-mix asphalt design method (mix design-1:7-6). In: Ninthinternational conference on asphalt pavements, Copenhagen, Denmark;August 2002. p. 36–47.

[12] Aschenbrener T. Comparison of results obtained from the French rutting testerwith pavements of known field performance. Colorado Department ofTransportation, Report no: CDOT-DTD-R-92-11; October 1992.

[13] Jansen Venneboer J, Van der Heide JPJ, Molenaar AAA. Asphalt constructionsfor heavy duty pavements and road widenings in the Netherlands, Eurasphalt& Eurobitume Congress; 1996.

[14] Aksoy A, _Iskender E. Creep in conventional and modified asphalt mixtures.Proc Inst Civil Engr Trans 2008;161(4):185–95.

[15] Kandhal PS, Cooley LA. Accelerated laboratory rutting tests: evaluation of theasphalt pavement analyzer, NCHRP REPORT 508, National CooperativeHighway Research Program, Transportation Research Board, Auburn, AL.Washington (DC): National Academy Press; 2003.

[16] Perret J, Dumont G, Turtschy C. Assessment of resistance to rutting of highmodulus bituminous mixtures using full-scale accelerated loading tests. 3rdEurasphalt & Eurobitume Congress Vienna 2004 – Paper 208 Book II – 1520.

[17] Valkering CP, Lancon DJL, Hilster ED, Stoker DA. Rutting resistance of asphaltmixes containing non-conventional and polymer-modified binders. In: AAPTConference. Albuquerque, USA; 19/21 February 1990.

Documents

Rutting evaluation of hydrated lime and SBS modified asphalt mixtures for laboratory and field compacted samples