Abstract:
Hot mix asphalt concrete (HMA) is being widely used to construct flexible pavements. The
HMA technology requires temperature in range of 150 to 190"C, which could cause many
environmental and health issues. Moreover, high temperature oxidizes bitumen and reduces
its design life and long-term performance of pavements. Researchers have reported that warm
mix asphalt (WMA) technology can help in reduction of mixing and compaction
temperatures by 20 to 40°C, and consequently promotes environmental and energy efficient
technology for construction of pavements. There are different types of warm mix additives as
organic, wax, chemical and water based. These additives are mixed with virgin binders to
reduce the viscosity of asphalt binder and felicitate good working conditions by reducing
temperature, emissions and increasing workability. However, concerns have been raised to
evaluate moisture, rutting and fatigue performance of WMA mixes. The less mixing
temperature in plant may reduce aging of a binder, which may result in high amount of
rutting in the field. However, limited studies are available on performance of binders
modified with WMA additives. Keeping the sustainability and energy saving requirements in
view, current study aims to evaluate laboratory performance of polymer modified binder
(PMB 40) modified with a wax based additives. Rutting performance using Superpave rutting
parameters (G*/Sin5), and multi-stress creep recovery tests (MSCR) were evaluated in the
laboratory for WMA modified and PMB 40 binders. It was found that addition of wax
additive enhances high temperature grade of a binder. Also, modification showed
improvement in rutting parameter (non-recoverable creep compliance) of a binder estimated
from MSCR test. Overall, it was seen that addition of a wax based WMA additive results in
improving rutting performance.
