Mechanical properties of reclaimed asphalt pavement mixtures with rejuvenator
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Date
2018-06
Authors
Ong, Ju Kit
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Abstract
In view of the ever-escalating demand for virgin aggregates and bitumen,
research efforts have now turned to reclaimed asphalt pavement (RAP) technology as the
solution for sustainable bituminous road construction. However, substituting virgin
materials with very high RAP contents would render the pavement vulnerable to cracking.
Thus, rejuvenator is incorporated to recuperate the performance of RAP mixtures. The
primary objective of this study is to investigate the effects of a rejuvenator on the
mechanical properties of asphalt mixtures incorporating 50% and 70% RAP contents in
terms of cracking and rut susceptibility. This study compares the performance of RAP
mixture with virgin mixture imparted with a strong antistripping agent. Overall,
conventional performance tests such as resilient modulus, indirect tensile strength and
notched SCB tests indicated that the rejuvenated mixtures performed comparably with
virgin mixtures, and outperformed non-rejuvenated RAP mixtures in the context of pure
tensile and tensile-shear fracture toughness and elastic deformation. Through algorithmic
modelling, it was also found that rejuvenated mixtures experienced relatively earlier
stripping in comparison with virgin and non-rejuvenated RAP mixtures in the dynamic
creep test. A new two-dimensional (2-D) imaging technique was innovated to better
understand the effects of rejuvenator on the stiffness of RAP mixtures in various fracture
tests. Image analysis was implemented with the use of geographic information system
(GIS) software. From this study, 2-D imaging technique revealed that the fracture path
and tensile strength of asphalt mixtures were governed by the stiffness of the mortar layer
at intermediate temperature, but influenced by the strength of aggregates at low
temperature. The effects of rejuvenator on the fracture surface characteristics of RAP
mixtures were found to be significant.