Evaluation of Warm Mix Asphalt Technology in Flexible Pavements [2018]

Warm mix asphalt (WMA) was first developed in Europe as an effort to reduce the greenhouse gas emission associated with asphalt pavement construction. In general, the WMA technologies can be divided into three categories: foaming techniques (water-based and water-bearing), organic or wax additives, and chemical additives. With the significantly lowered production temperature of WMA technologies, using them would bring benefits such as reduced fuel usage and emissions, easier compaction, possible use of higher percentage of RAP, extended paving season, longer haul times and distances, and improved job site conditions for workers. Nevertheless, the lower mixing temperatures have raised concerns that the aggregate may contain water and yield a mixture that is susceptible to moisture damage. Another concern is that the asphalt binder may not possess adequate stiffness characteristics at elevated pavement surface temperature, thereby resulting in rutting susceptibility. These considerations bring up the need to thoroughly evaluate the WMA mixtures to ensure an adequate pavement performance