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Geotechnical News • June 2014
www.geotechnicalnews.com
THESIS ABSTRACTS
Laboratory Characterization of Recycled
and Warm Mix Asphalt for Enhanced
Pavement Applications
Rouzbeh Ghabchi
Rouzbeh Ghabchi, School of Civil Engineering and Environmental
Science, The University of Oklahoma, 202 W. Boyd St., Room:
CEC 334, Norman, OK 73019, email: ghabchi@ou.edu.
Over the past two decades, many transportation agencies,
asphalt producers, and pavement construction companies
have taken major initiatives to implement green paving
technologies. Saving energy during asphalt production and
increased use of reclaimed asphalt materials are important
elements of such initiatives. Consequently, there is a need
for the characterization of the associated mixes for their
performance and Mechanistic-Empirical Pavement Design
Guide (M-EPDG) input parameters. The present study
addresses two areas of green pavements: characterization
of warm mix asphalt (WMA) and characterization of hot-
mix asphalt (HMA) containing higher amounts of reclaimed
asphalt pavement (RAP) and reclaimed asphalt shingles
(RAS) than normally used in Oklahoma. It was found that
the WMA mixes have lower dynamic modulus (lower stiff-
ness), reduced potential of low temperature cracking, lower
fatigue life, and a higher rutting potential compared to their
HMA counterparts. For mixes containing RAP and/or RAS, it
was found that dynamic modulus increases and creep compli-
ance reduces, with an increase in the amount of RAP and/or
RAS. The fatigue life was found to increase with an increase
in RAP content up to 25%, and to decrease when the RAP
and/or RAS content exceeds 25%. Increased resistance to
rutting and moisture-induced damage was observed, with an
increase in the amount of RAP and/or RAS. The Surface Free
Energy (SFE) study on WMA additives revealed that Saso-
bit
®
, Advera
®
and Evotherm
®
reduced the moisture suscepti-
bility of the WMA, except when Sasobit
®
and Advera
®
were
used with granite. Also, it was found that the resistance to
moisture-induced damage increased with an increase in RAP
content. Moreover, a new composite energy ratio parameter,
based on the job-mix formula and SFE parameters, was pro-
posed and shown to be capable of evaluating the moisture-
induced damage potential of the tested asphalt mixes. The
findings of this study are expected to be useful in understand-
ing the effects of using different WMA technologies, RAP,
Laboratory Characterization of Recycled and Warm Mix Asphalt for Enhanced Pavement Applications
Rouzbeh Ghabchi, The University of Oklahoma
Simulation of Failure Mechanisms around Underground Coal Mine Openings using Discrete Element
Modelling
Fuqiang Gao, Simon Fraser University
Soil Restraints on Steel Buried Pipelines Crossing Active Seismic Faults
O. Manuel Monroy-Concha, University of British Columbia
Quantitative Risk Assessment of Natural and Cut Slopes: Measuring Uncertainty in the Estimated and
Proposed Framework for Developing Risk Evaluation Criteria
Renato Macciotta, University of Alberta
High Stress Flow Behaviour and Constitutive Modeling of Dry Granular Materials
Abraham Enawgaw Mineneh, University of Alberta
Application of Dewatering Technologies in Production of Robust Non-Segregating Tailings
Reza Moussavi Nik, University of Alberta
Stabilization of Oil Sands Tailings Using Vacuum Consolidation
Ehsan Abazari Torghebeh, University of Alberta
Re-Visitation of Actual Evaporation Theories
Dat Tien Quoc Tran, University of Alberta
Understanding and Predicting Excavation Damage in Sedimentary Rocks: A Continuum Based Ap-
proach
Matthew A Perras, Queen’s University
Durability of HDPE Geomembranes for Municipal Solid Waste Landfill Applications
Fady Badran Abdelaal, Queen’s University
Performance of Geosynthetic Clay Liners in Cover, Subsurface Barrier, and Basal Liner Applications
Mohamed Said Hussein Hosney, Queen’s University
Longevity of HDPE Geomembranes in Geoenvironmental Applications
A. M. R. Ewais, Queen’s University
Interpretation of Pumping Tests in Confined Aquifers in the Case of Interferences
(Original title in French: Interprétation des essais de pompage dans les aquifères à nappe captive en cas d’interférences)
Simon Weber, Ecole Polytechnique