EFFECTS OF A CHEMICAL WMA ADDITIVE ON AGING CHARACTERISTICS OF BITUMINOUS MIXTURES

Utilization of warm mix asphalt (WMA) in pavement construction is a relatively new technology, therefore there is nearly no chance to practically evaluate the long-term characteristics of the existing WMA pavements. Due to lower application temperatures, it can intuitively be expected that a WMA pavement would be less subjected to aging-induced failures. This study attempts to evaluate the effects of a chemical WMA additive on aging characteristics of bituminous mixtures. The chemical additive tested within the scope of this study is a combination of both organic additive and a kind of cationic surfactant developed by Akzo Nobel. Short-and long-term aging conditions were simulated on mixtures containing various contents of chemical WMA additive as well as on control specimens. To estimate the proportions of hardening, aging indices were determined based on indirect tensile strength (ITS) results. The aging indices unveiled that the specimens containing chemical WMA additive demonstrate higher resistance against hardening than conventional hot mix asphalt (HMA) specimens