Selection of type of warm mix asphalt additive based on the rheological properties of asphalt binders

This paper presents a methodology to characterize the changes in the rheological properties of unaged and aged asphalt binders incorporating various Sasobit® and Rediset® contents at high and intermediate temperatures. The changes in the rheological properties of asphalt binders per 1% Sasobit® and Rediset® contents were measured using new proposed parameters namely the non-dimensional viscosity index (∇ηs), gradients of the Superpave™ rutting factor (∇NSRP) and relative G*sin (δ) (∇RG). The results of ∇ηs showed that although both additives reduce binders' viscosities, the decrease per 1% additive depends on test temperature, aging state, asphalt and additive type. The results of flow test also showed that Rediset® does not change the Newtonian behavior of asphalt binder, while Sasobit® converts the Newtonian flow into non-Newtonian at some specific shear rates, which this effect was defined in terms of threshold of non-Newtonian flow (TNF). Based on the results of the rheological binder tests, three viable scenarios to select Sasobit® or Rediset® based on the sustainability and structural performance were introduced