Stripping performance of Hot Mix Asphalt (HMA) using polymer and hydrated lime as additives / Ekarizan Shaffie

Stripping is one of the common type of pavement failure found in asphaltic pavements.
Besides high traffic impact stress, climatic factor such as temperature and moisture also
have profound effect on the durability of hot mix asphalt (HMA) pavements. The
objective of this research is to evaluate and compare the stripping performance of
unmodified and rubber-polymer modified binder mixes with and without anti-stripping
additives in Superpave mix design (AASHTO TP4) procedure.
The study investigates four different dense graded Superpave HMA mixes. The first
mixture was a control specimen that contained no hydrated lime and unmodified binder.
The second mixture contained hydrated lime with unmodified binder. The third mixture
contained no hydrated lime but with rubber-polymer modified binder and the fourth
mixture contained hydrated lime with rubber-polymer modified binder. The hydrated
lime was used as anti-stripping additive. The addition of 40-mesh tyre crumbs and
polymer Ethylene-Vinyl-Acetate (EVA) into binder was used to prepare rubber-polymer
modified binder. The optimum percentage of rubber crumb and EVA polymer was
selected based on the previous research done by Ibrahim, (2005). The boiling water test,
the modified Lottman's test, and the indirect tensile resilient modulus test were used to
evaluate the stripping performance in these mixes. This study also documents the effect
of different temperature on tensile strength ratio (TSR) and resilient modulus ratio
(RMR) on the HMA mixtures. Comparison of the physical conditions such as strength or
resilient modulus of the conditioned and unconditioned samples were used as a measure
to evaluate the stripping potential in HMA pavement. Statistical analysis was then
carried out to evaluate the significance of rubber polymer and hydrated lime on the
stripping performance of HMA mix.