A study on the effects of surface-activated warm-mix additives on the rheological properties and compaction characteristics of ultra-high-viscosity asphalt

Ultra-thin overlays using ultra-high viscosity asphalt (UHVA) require high temperatures and energy. This study evaluated two surface-active warm-mix additives, WMH (nonionic) and EM (cationic), on the properties of UHVA. FTIR confirms both additives physically blend with UHVA. A One-way ANOVA was utilized to screen highly sensitive core indicators, which subsequently constructed a multi-dimensional radar chart for optimization. WMH reduces 175°C rotational viscosity by 15.6% (whereas EM has no significant effect), and both additives significantly reduce dynamic viscosity by up to 50%. 0.5% WMH decreases J nr3.2 by 34.2%, while 0.3% EM decreases J nrdiff by 26.1%. EM improves the m-value by up to 13.7%, whereas 0.5% WMH extends Nf by 73.6%. Based on the radar chart, 0.5% WMH and 0.3% EM were identified as the optimum contents. Finally, at optimal contents, the WMH mixture requires the least compaction energy, and the "wet method" reduces compaction resistance more effectively than the "dry method".