Prediction of Stiffness of Asphalt Treated with Surfactant-Based Warm-Mix Additive

Although the tonnage of asphalt pavements constructed with warm-mix technologies has increased rapidly in the United States in recent years, some practical aspects of warm-mix asphalt pavement construction remain incompletely defined. For example, compaction temperatures for many warm-mix technologies cannot be estimated with the standard equiviscous methods common to hot-mix asphalt. This paper reports the preliminary results of research to develop a method for predicting the stiffness (G*/sin δ) of binder treated with a surfactant-based warm-mix additive as a function of mix production temperature, mix storage and haul time, and warm-mix additive dosage. Asphalt binders were treated in the laboratory with 0.0%, 0.5%, and 1.0% of surfactant-based warm-mix additive and were heated in a rolling thin-film oven at 130°C, 145°C, and 163°C for 0, 25, 55, 85, and 115 min. Regression analyses of the laboratory data yielded equations that with good fit correlated binder stiffness with the formulation (dosage) and...