Utilization and Laboratory Evaluations of Mixes Containing Reclaimed Asphalt Pavement
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Date
2020-04
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Addis Ababa University
Abstract
Developing technologies in the construction industry, that provide sustainable solutions for future
pavement condition is vital given the ever-increasing demand on the supply of bitumen and good
quality pavement construction materials. Reclaimed asphalt pavement (RAP) is formed by cold
milling, heating, softening and removal of the existing aged asphalt pavement, full-depth removal
of plant waste hot mixed asphalt (HMA) materials. The research investigates to efficiently utilize
and assess the impact of RAP in asphalt mixes. The evaluation involved Nine mix designs of
control mixes and partially substituted mixes. Out of the nine mixes, four are used as control mixes
and the other five are checked for the comparative advantages of partially substituted mixes.
Laboratory testing was accomplished in the control mix with the production of Marshall compacted
specimens to determine the performance of Hot Mix Asphalt using Marshall Mix design methods and
parameters such as air voids, voids in mineral aggregate, voids filled with asphalt cement, Marshall
Stability and flow are measured. Then after optimum bitumen content was obtained from the control
mixes. Besides this, the optimum bitumen content is determined for a partially substituted mix.
For the selected optimum bitumen content, Three samples from each mix which partially substitution of
RAP with (10, 20, 30 and 40) % by weight of RAP. To examine the rutting resistance of the RAP
samples rutting test were conducted by wheel tracking. In addition to this Indirect Tensile Strength tests
were conducted to evaluate the moisture susceptibility of the sample and the three samples (i.e.
10%,20%,30%) prevails that the samples were not susceptible to water and the figures were above the
specification (80%).
Finally, the performance test result of laboratory RAP sample tests provided that using 20% by
weight of RAP is strongly suggested. The laboratory result and other relevant parts of the thesis
are illustrated.
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Keywords
RAP, Indirect Tensile Strength, Marshal Stability, Flow, Rutting