Balancing the Performance and Environmental Concerns of Used Motor Oil as Rejuvenator

in Asphalt MixesEslam Deef−Allah1, Magdy Abdelrahman1, Mark Fitch1, Mohyeldin Ragab2, Mousumi Bose3 and Xiaolong He3

1 Department of Civil, Architectural, and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO, 65409, USA

2 Research and Technology at Pure Asphalt Company, Chicago, IL 60526, USA

3 Department of Chemistry, Missouri University of Science and Technology, Rolla, MO, 65409, USA

Road deterioration inspires researchers to enhance the properties of

asphalt binder for better performing mixes. Recycled tire rubber, or

crumb rubber modifier (CRM), and used motor oil (UMO) are two

modifiers that enhance asphalt binder performance through two

different mechanisms. CRM affects high-temperature properties

while UMO modifies low-temperature properties.

I. INTRODUCTION

1. Check the BTEX components for asphalt binders modified with

CRM and UMO and check that leachate components for

modified asphalt mixtures with CRM and UMO within

Environmental Protection Agency (EPA) limits.

2. Enhance the asphalt binder rheological properties through

using recycled materials (CRM and UMO).

3. Restoration of aged asphalt binders to original constitutes and

behavior through using rejuvenators (UMO).

II. OBJECTIVES

PG 52-28 asphalt binder was added to a 1-gallon can, heated to 170

°C in an oven, and transferred to a hot plate under a fume hood. Then

15% CRM of asphalt binder weight was added at time zero. Asphalt

binder with CRM was mixed at high speed (50 Hz) for 75 min.

For the sample modified by UMO, 2.5% UMO by weight of asphalt

binder was added after 2 min of interaction between CRM and

asphalt binder, then mixing continued to the end of 75 min.

Both CRM and UMO percentages were selected based on previous

researches [1,2].

1. Abdelrahman, M.; Ragab, M.; Bergerson, D. Effect of Used Motor Oil on the Macro and Micromechanical

Properties of Crumb Rubber Modified Asphalt. Int. J. Waste Res. 2015, 5.

2. Ragab, M.; Abdelrahman, M. Investigation of the Physical and Molecular Properties of Asphalt Binders

Processed with Used Motor Oils. J. Mater. 2015, 2015, 632534.

III.INTERACTIONS AND MIXING PROCEDURES

IV.PORTABLE GAS CHROMATOGRAPHY

RESULTS (BTEX COMPONENTS)

TABLE 1. Interaction conditions for the modified asphalt binders.

0

0.5

1

1.5

2

2.5

3

AC at 2 min AC at 12

min

AC at 22

min

AC at 32

min

AC at 42

min

AC at 52

min

AC at 62

min

Co

nce

ntr

atio

n i

n a

ir

(pp

b)

(a) Neat asphalt binder

0

0.5

1

1.5

2

2.5

3

AC+CRM at

2 min

AC+CRM at

12 min

AC+CRM at

22 min

AC+CRM at

32 min

AC+CRM at

42 min

AC+CRM at

52 min

AC+CRM at

62 min

Co

nce

ntr

atio

n i

n a

ir

(pp

b)

(b) AC + 15% CRM

0

0.5

1

1.5

2

2.5

3

AC+CRM+UMO

at 2 min

AC+CRM+UMO

at 12 min

AC+CRM+UMO

at 22 min

AC+CRM+UMO

at 32 min

AC+CRM+UMO

at 42 min

AC+CRM+UMO

at 52 min

AC+CRM+UMO

at 62 min

Co

nce

ntr

atio

n i

n a

ir

(pp

b)

(c) AC + 15% CRM + 2.5% UMO

Benzene Toluene Ethylbenzene m,p-Xylene o-Xylene

FIGURE 1. BTEX in air above PG 52-28 neat and modified asphalt

binder samples interacted at 170 °C—50 Hz and different interaction

times.

0

100

200

300

400

-12 -18 -24 -30

Sti

ffn

ess

(MP

a)

Temperature (°C)

(a) Stiffness

Neat

Neat + 15%CRM

Neat + 15%CRM + 2.5%UMO

Specification limit lower than this line

0

0.1

0.2

0.3

0.4

-12 -18 -24 -30

m-v

alu

e

Temperature (°C)

(b) m-value

Neat

Neat + 15%CRM

Neat + 15%CRM + 2.5%UMO

Specification limit higher than this line

FIGURE 3. BBR test results measured for PG 52-28 neat and modified asphalt binder samples

interacted at 170 °C—50 Hz—75 min.

VI.ASPHALT MIXTURES RESULTS

0

1

2

3

4

5

6

Neat Mix Neat +

15%CRM +

2.5% UMO

Neat +

15%CRM

EPA

Maximum

Standard

Co

nce

ntr

atio

n (

mg

/L)

As (arsenic) Cd (cadmium) Cr (chromium )

Pb (lead) S (sulfur) Fe (Iron)

2,000,000

4,000,000

6,000,000

8,000,000

6 8 10 12 14 16 18

|G*

|. si

nδ

( P

a)

Temperature (°C)

(b) PAV-aged samples

Specification "Lower than this line" Neat, PAVNeat + 15%CRM + 2.5%UMO, PAV Neat + 15%CRM, PAV

0

1,000

2,000

3,000

4,000

5,000

50 55 60 65 70 75 80

|G*

|/si

nδ

(Pa)

Temperature (°C)

(a) Unaged and RTFO-aged

Neat + 15%CRM + 2.5%UMO, unaged Neat + 15%CRM, unagedNeat, RTFO Neat + 15%CRM + 2.5%UMO, RTFONeat + 15%CRM, RTFO Unaged "Greater than this line"

V. ASPHALT BINDER RHEOLOGICAL

RESULTS

FIGURE 2. Rheological properties for PG 52-28 neat and modified

asphalt binders interacted at 170 °C—50 Hz—75 min.

0

2

4

6

8

0 2,000 4,000 6,000 8,000

Ru

ttin

g d

epth

(m

m)

No of cyclesNeatNeat + %15 CRM + %2.5 UMONeat + %15 CRM

FIGURE 5. Rutting depth for PG 52-28 neat

and modified asphaltic mixtures samples

(APA testing).

FIGURE 4. Toxicity Characteristic Leaching

Protocol (TCLP) results for PG 52-28 neat and

modified mixtures compared to EPA standards

for heavy metals.

This study confirms that engineered CRM-UMO combinations can regulate

the rheological properties of asphalt binders without causing harm to the

environment. It is recommended that UMO percentage be less than 3%, and

that UMO should be used only after testing random samples collected from

different sources to ensure that air emissions and leachate are within applicable

regulations.

VII.CONCLUSIONS AND RECOMMENDATIONS

Resources for conducting this research were provided by Missouri University

of Science and Technology. NovaTest Portable GC-PID was provided by

Nanova Environmental, Inc. (Columbia, Mo, USA).

VIII.ACKNOWLEDGEMENT

Asphalt

binder

CRM

%

UMO

%

Interaction

Temperature (C)

Interaction

Speed (Hz)

Interaction

Time (min)

Modified Asphalt

Binder Code

PG 52-28 15

0

170 50 75

Neat PG 52-

28+15%CRM (170 C-

50Hz-75min)

2.5

Neat PG 52-

28+15%CRM+2.5%UM

O (170 C-50Hz-75min)