Influence of warm mix asphalt additive on selected properties of asphalt concrete for wearing courses with highly polymer modified bitumen and RAP

The paper presents the results of research on the simultaneous use of reclaimed asphalt pavement (RAP), highly polymer modified binder and selected warm mix asphalt (WMA) additive in asphalt concrete for wearing course. The scope of the research included evaluation of the characteristics of compactability, resistance to permanent deformation, resistance to water and frost damage, as well as assessing the influence of short- and long-term ageing. Three types of mixtures were tested: 1) reference mixture without RAP, 2) mixture with RAP with binder replacement (BR) ratio of the level of 26% and 3) mixture with RAP with the same BR ratio and WMA additive. Mixtures 1) and 2) were prepared and compacted at 160°C and 145°C while mixing and compaction temperatures for mixture 3) were 145°C and 115°C, respectively. The obtained results indicate that there are no reasons not to use simultaneously highly polymer modified bitumen with WMA additive in a mixture containing RAP, which in fact improved compactability characteristics. However, the issue of resistance to environmental factors (water and frost) requires further research as mixture with RAP and WMA additive did not meet required level of resistance to water and frost damage.