Abstract

The objective of this study is to evaluate the effect of different fillers on the performance properties of asphalt emulsion mixtures (AEM). Six types of fillers were used, including limestone filler (LF), hydrated lime (HL), fly ash (FL), slag powder (SG), composite Portland cement (CPC), and ordinary Portland cement (OPC). The AEM design was conducted using a two-stage process to allow for determination of the optimum water content (OWC) and optimum emulsion content (OEC). The effect of the fillers on the mixture performance was evaluated based on moisture susceptibility as measured by the indirect tensile test and rutting resistance measured by loaded wheel testing. To better understand observed differences in performance, the environmental scanning electron microscope (ESEM) was used to obtain the microstructure of different filler-emulsion combinations. Test results indicate that the physical and chemical properties of fillers significantly affect both mixture design and performance. Furthermore, the most effective fillers are found to be materials that include cement or hydrated lime as the reaction between these materials, and the water in the emulsion has a reinforcing effect on binding the aggregates together. Conversely, with replacement of a portion of the limestone filler with fly ash or slag powder, no effects on moisture susceptibility or rutting resistance relative to the control mix were observed. ESEM images confirmed that hydration products are formed when the water in the emulsion reacts with cement or slag, causing the increase in performance properties. The proposed mechanisms by which the hydration reaction improves performance include increasing the degree of compaction and rigidity of AEM as well as increasing the strength of the adhesive bond at the asphalt emulsion aggregate. Based on the findings of this study, it is recommended that filler chemical and physical properties should be used to select materials most appropriate for use in AEM.

References

1.
Asphalt Cold Mix Manual
,”
Manual Series No. 14
, 3rd Edition,
Asphalt Institute
,
Lexington, KY
,
1997
.
2.
Santucci
,
L. E.
, “
Thickness Design Procedure for Asphalt and Emulsified Asphalt Mixes
,”
Proceedings of the 4th International Conference on the Structural Design of Asphalt Pavements
,
Ann Arbor, MI
, Aug 22–26,
1977
, pp.
424
456
.
3.
Asphalt Institute
,
2008
, “
Thickness Design: Asphalt Pavements for Highways and Streets
,”
Manual Series No. 1
, 9th ed.,
Asphalt Institute
,
Lexington, KY
.
4.
James
,
A.
, “
Overview of Asphalt Emulsion
,”
Asphalt Emulsion Technology, Transport Research Circular No. E-C102
,
Transportation Research Board
,
Washington, D.C.
,
2006
, pp.
1
15
.
5.
Khweir
,
K.
,
Fordyce
,
D.
,
Strickland
,
D.
, and
Read
,
J.
, “
Effect of Curing Time and the Performance of Cold Asphalt Mixtures
,”
Proceedings of the 3rd Eurasphalt and Eurobiume Congress
,
Vienna, Austria
, May 12–14,
2004
, p. 144.
6.
Anderson
,
D. A.
, “
Guidelines for Use of Dust in Hot Mix Asphalt Concrete Mixtures
,”
Proc. Assoc. Asphalt Paving Technol.
, Vol.
56
,
1987
, pp.
492
516
.
7.
Bahia
,
H. U.
,
Faheem
,
A.
,
Hintz
,
C.
,
Al-Qadi
,
I.
,
Reinke
,
G.
, and
Dukatz
,
E.
, “
Test Methods and Specification Criteria for Mineral Filler Used in HMA
,”
NCHRP Research Results Digest 357
,
Transportation Research Board
,
Washington, D.C.
,
2011
.
8.
Kandhal
,
P. S.
,
Lynn
,
C. Y.
, and
Parker
,
F.
, “
Characterization Tests for Mineral Fillers Related to Performance of Asphalt Paving Mixtures
,”
Report No. 98-2
,
NCAT
,
Alexandria, VA
,
1998
.
9.
Bahia
,
H. U.
,
Zhai
,
H.
,
Bonnetti
,
K.
, and
Kose
,
S.
, “
Non-Linear Viscoelastic and Fatigue Properties of Asphalt Binders
,”
J. Assoc. Asphalt Paving Technol.
, Vol.
68
,
1999
, pp.
1
34
.
10.
Geber
,
R.
and
Gomze
,
L. A.
, “
Characterization of Mineral Materials as Asphalt Fillers
,”
Mater. Sci. Forum
, Vol.
659
,
2012
, pp.
471
476
. https://doi.org/10.4028/www.scientific.net/MSF.659.471
11.
Zulkati
,
A.
,
Diew
,
W.
, and
Delai
,
D.
, “
Effects of Fillers on Properties of Asphalt-Concrete Mixture
,”
J. Transport. Eng.
, Vol.
138
, No.
7
,
2012
, pp.
902
910
. https://doi.org/10.1061/(ASCE)TE.1943-5436.0000395
12.
Terrel
,
R. L.
and
Wang
,
C. K.
, “
Early Curing Behavior of Cement Modified Asphalt Emulsion Mixtures
,”
Proc. Assoc. Asphalt Paving Technol.
, Vol.
40
,
1971
, pp.
108
125
.
13.
Li
,
G.
,
Zhao
,
Y.
,
Pang
,
S. S.
, and
Huang
,
W.
, “
Experimental Study of Cement-Asphalt Emulsion Composite
,”
Cement Concrete Res.
, Vol.
28
, No.
5
,
1998
, pp.
635
641
. https://doi.org/10.1016/S0008-8846(98)00038-6
14.
Brown
,
S. F.
and
Needham
,
D.
, “
A Study of Cement Modified Bitumen Emulsion Mixture
,”
Proc. Assoc. Asphalt Paving Technol.
, Vol.
69
,
2000
, pp.
92
121
.
15.
Oruc
,
S.
,
Celik
,
F.
, and
Akpinar
,
M. V.
, “
Effect of Cement on Emulsified Asphalt Mixtures
,”
J. Mater. Eng. Perform.
, Vol.
16
, No.
5
,
2007
, pp.
578
583
. https://doi.org/10.1007/s11665-007-9095-2
16.
European Committee for Standardization, EN 933-9
,
2009
, “
Tests for Geometrical Properties of Aggregates. Assessment of Fines. Methylene Blue Test
,”
European Committee for Standardization
,
Brussels, Belgium
.
17.
Ministry of Transport of the People’s Republic of China, JTJ E02-2011
,
2011
, “
Standard Test Methods of Bitumen and Bituminous Mixtures for Highway Engineering
,”
China Communication Press
,
Beijing, China
.
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