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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)