Impact of addition of greasy diamide on the rheological-mechanical properties of warm-mix asphalt

Warm-mix asphalt (WMA) containing additives is used to decrease both the costs and harmful effects to the environment by reducing the viscosity, mixing temperature and compaction energy of asphalt without affecting its mechanical and dynamic properties. The lubricity effect is important in the densification of the mixture and must be measured during compaction (using a Superpave gyratory compactor). This work analyzes the impact of the addition of greasy diamide (DG) on the theological-mechanical properties of dense-grade mixtures manufactured with asphalt AC-20 by examining a reference sample (HMA) and three improved samples (WMAs) with different percentages (1.5, 3.0 and 4.5%) of greasy diamide. The type of aggregate, content and type of asphalt and compaction energy were found to remain constant in the test mixtures. The rheological properties were measured according to current regulations, and the deformation was determined using a uniaxial cyclic compressive tester and a Hamburg loaded wheel. The results showed that the addition of greasy diamide to WMA improved the rheological properties while decreasing the compaction temperature and maintaining densification without significantly affecting the mechanical behavior. (C) 2019 Elsevier Ltd. All rights reserved.