Effects Of Rh-Wma Additive On The Rheological Properties Of Reclaimed Asphalt Binders And The Engineering Properties Of Recycled Mixtures
Reclaimed asphalt pavement (RAP) utilization is an option as a sustainable pavement due to its economic and environmental benefits. However, the use of high RAP content in pavement construction implicates high production temperature and hence increasing energy consumption and environmental pro...
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| Format: | Thesis |
| Language: | English |
| Published: |
2017
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| Subjects: | |
| Online Access: | http://eprints.usm.my/46025/1/Effects%20Of%20Rh-Wma%20Additive%20On%20The%20Rheological%20Properties%20Of%20Reclaimed%20Asphalt%20Binders%20And%20The%20Engineering%20Properties%20Of%20Recycled%20Mixtures.pdf |
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| Summary: | Reclaimed asphalt pavement (RAP) utilization is an option as a sustainable pavement
due to its economic and environmental benefits. However, the use of high RAP content
in pavement construction implicates high production temperature and hence increasing
energy consumption and environmental problems during the asphalt mixture
production. Higher asphalt mixture production and compaction temperatures are
needed because the RAP binder is oxidized and stiffened. Asphalt mixtures with very
high stiffness are more susceptible to fatigue failure. This explains the reason why
RAP usage is limited particularly in areas with high amount of aggregates resources.
Therefore, this research investigates the performance of a relatively new warm mix
asphalt (WMA) additive named RH-WMA additive to reduce asphalt production
temperatures. The optimum RH-WMA content was determined through asphalt binder
rheological tests. A total of 3% RH-WMA additive by mass of asphalt binder, was
incorporated into the recycled asphalt binder and mixture. The effects of RH-WMA
additive on recycled asphalt binder and mixture were investigated via chemical
properties, rheological properties and mixtures performance test, respectively. The test
results showed that the incorporation of RH-WMA additive with asphalt binder
decreased the viscosity at high temperature and improved fatigue resistance at
intermediate temperature. Viscosity reduction was also observed when RH-WMA
additive incorporated with recycled asphalt binder and hence indicated the potential to
reduce the production temperature of the RAP mixture. The Fourier Transform
Infrared (FTIR) test result showed the ability of RH-WMA additive to reduce the
effects of aging. The reduced effects on aging is also shown in the rheological master
curves at high frequency and/or low temperature. From the rheological master curves,
the addition of RH-WMA additive increased the complex modulus and reduced the
phase angle values compared to the control sample. This observation showed that the
recycled asphalt binder incorporated with RH-WMA additive showed potential
improvement in rutting resistance. The optimum binder content (OBC) results based
on response surface method (RSM) and multi criteria optimization in recycled asphalt
mixture with RH-WMA additive production indicated the significant effects of mixing
temperature on the OBC. The performance of recycled asphalt mixtures were
improved in terms of stiffness and resistance to rutting. However, the asphalt mixture’s
ability to resist fatigue decreased considerably when stiffer RAP from locations R1
and R3 were incorporated in the virgin mixture. The incorporation of RH-WMA
additive improved the mixture’s resistance to fatigue. The combined effects of
moisture and aging also decreased the fatigue resistance of all mixture types in
comparison with unconditioned specimen. In general, the addition of RH-WMA
additive can potentially balance the adverse effects of RAP stiffness and hence
maximize the benefits of RAP usage. |
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