An investigation of factors affecting the moisture sensitivity of warm mix asphalt (WMA)

Looking for of increased pollution and environmental concerns, as well as rising fuel and energy prices, the Warm Mix Asphalt (WMA) technology has been introduced as an environmentally friendly technology, and Nowday the direction of the pavement industry has become more widely used. WMA asphalt technology, despite the reduction in production and compaction temperature and density and other advantages comparing to Hot Mix Asphalt (HMA), has a weakness in moisture damage, which is one of the main concerns of this technology, and the use of Anti-stripping additive is one of the most widely used methods to reduce this damage. Asphalt mixtures of WMA are composed of different materials such as bitumen, aggregate and WMA additives, and the study of the effect of each of these materials on the reduction of moisture sensitivity less attention has been investigated. Therefore, in this study in order to aware of road engineers to improve this problem with this type of asphalt mixture will be discussed. Studies have shown that the type of aggregate (characteristics of acidity or alkalinity), the type of WMA additive, and mixing and compaction temperature are among the most important factors affecting the WMA asphalt mixture resistance, which indirectly affects the pavement.