Multiperformance Evaluation of Surfactant Foaming Warm-Mix Asphalt Containing Recycled Asphalt Mixtures

To quantify the synergistic effects of surfactants and foaming process on the compaction and mechanical characteristics of asphalt mixtures, a foaming test was carried out to determine the optimal foaming conditions for foam warm mix asphalt. The compaction and mechanical characteristics of warm mix recycled asphalt mixture (SFMA-40% RAP) were comprehensively evaluated through indoor tests. A hot mix recycled asphalt mixture (HMA-30% RAP) and water foam warm mix recycled asphalt mixture (FMA-40% RAP) were used for comparison. The results showed that surfactant foaming warm mix asphalt exhibited optimal foaming effect at 160°C with 0.3% surfactant dosage, attaining a foam half-life over 200 s. Under the same compaction conditions, SFMA-40% RAP had the best compaction effect, followed by water foam warm mix recycled asphalt mixture. Hot mix recycled asphalt mixture had the poorest compaction effect. Due to the synergistic effect of surfactants and foaming processes, the adverse effects of foaming water and RAP on the mechanical properties of asphalt mixtures were reduced. Therefore, SFMA-40% RAP exhibited enhanced resistance to rutting, cracking, moisture damage. SFMA-40% RAP exhibited only 2.58% lower fatigue life than HMA-30% RAP, demonstrating significantly enhanced durability for pavement service. The research results proved the application potential of surfactant foaming warm mix asphalt in high content recycled asphalt pavement.