Page 10 - Climate Conference - EBook 2023: Al-Qasemi Academy

Use of Recycled Asphalt in Roads Construction:

Laboratory Performance and Environmental and Cost
Impacts
Dr. Asi Ibrahim

Manager of Regional Centre of Excellence for Pavement Studies &
Evaluation, Arab Centre for Engineering Studies (ACES)

ABSTRACT
The resulting materials during roadways maintenance and rehabilitation activities are
usually known as Reclaimed Asphalt Pavements (RAP). RAP materials, if properly
processed, will consist of high quality, well-graded asphalt coated aggregates. RAP can be
used in many highway construction applications as an aggregate substitute and asphalt
cement supplement in recycled asphalt paving. In addition, it can be used as a granular
base or subbase, stabilized base aggregate, or as an embankment or fill material.
This study aimed at evaluating the mechanical performance of the asphalt mixes
containing collected RAP materials from three roads at four different percentages of RAP
addition, (0%, 5%, 10% and 15%). It was concluded that the inclusion of the RAP in the
asphalt mixes improved all the mechanical properties of the mixes. However, due to the
marginal properties of one of the used RAP materials sources, it was found that, 10% RAP
was the optimal replacement percentage for all the used RAP sources.
In addition, the study assessed the environmental and cost impacts of utilizing RAP in the
asphalt mixes. The results indicated that the utilization of RAP in asphalt pavements is very
advantageous from different perspectives. Some of the advantages of utilizing RAP
include saving of energy, reducing emissions, conservation of asphalt and aggregate
resources, reduction in pavement life cycle cost, and reduce landscape disfigurement,
disruption of natural vegetation, soil erosion and sedimentation. From the cost impact
analysis, it was indicated that using 20% RAP will save 7.85$/ton (17.7% cost reduction),
which is equivalent to 0.88 $/sq.m. of HMA layer with 5 cm layer thickness. This implies
that using RAP is beneficial in many technical, economical and environmental fields.

Keywords: RAP, Cost Impact, Environmental Impact.

Biography: Dr. Ibrahim M. Asi working as Manager of Regional Excellence Centre for Pavement
Studies and Evaluation, at Arab Centre for Engineering Studies (ACES), Amman, Jordan from 2010 up
to date. Obtained his B.Sc. in Civil Engineering in 1983, M.Sc. in 1986 and Ph.D. in Transportation,
Pavement Materials option in 1996, from King Fahd University of Petroleum & Minerals (KFUPM),
Dhahran, Saudi Arabia. Worked for five years as an Assistant Professor at KFUPM, and nine years as
an Assistance and Associate Professor in the Civil Engineering Department at Hashemite University
in Zarqa, Jordan. Taught over thirty short courses, completed twenty funded research projects,
authored over 120 journal and conference papers that appeared in leading international periodicals
and conference proceedings. His fields of expertise are highway and airport materials, polymer
modification, pavement design, construction specifications, pavement