Hot Mix Asphalt (HMA) experiences degradation due to the combined effects of cyclic traffic loading, thermal variations,
and moisture exposure. While various additives have been formulated to enhance HMA durability, individual additives
often fail to demonstrate adequate performance across diverse environmental exposures. This investigation employed a
dual-additive approach incorporating Carbon Fiber (CF) and Nano-silica (NS) to enhance the durability and mechanical
characteristics of asphalt mixtures. The study incorporated CF concentrations ranging between 0.1 and 0.5% relative to
total mixture weight, while NS concentrations ranged between 2 and 10% relative to binder weight. Evaluation of the
modified mixtures encompassed mechanical and durability assessments through ITS, WLT, M.I., and TSR testing protocols,
complemented
by
SEM,
EDX,
and
ANOVA
analytical
techniques.
Results
indicated
that
CF
at
0.3%
concentration

enhanced
crack
resistance, while
NS at 8% concentration demonstrated
superior
moisture durability; there
was also found
to

be synergistic interaction between these two modifiers that enhanced durability, stiffness, and crack resistance while
having an initial cost higher than the control but with superior performance (i.e., longer service life), which may indicate
technical feasibility as well as economic viability for using a dual-modified mixture in modern pavement applications.