Determination of moisture susceptibility characteristics of polymer modified hot-mixed asphalt

By the increase in traffic volume, tire pressure, axle load and changes in environmental conditions cause serious premature failures in pavements such as rutting, fatigue and low temperature cracking as well as moisture induced damage. One of the major causes of premature pavement failure is also the moisture induced damage of asphalt concrete layer. Many variables affect the amount of water damage in asphalt concrete layer such as the type of aggregate, bitumen, mixture design and construction, level of traffic, environment and the additive properties that are introduced to the bitumen, aggregate or bitumen-aggregate mixture.This study is the aimed to determine the effect of additives such as elastomeric (SBS) and plastomeric (EVA) polymer modified bitumen (PMB) on the stripping potential and moisture susceptibility characteristics of hot mix asphalt (HMA) containing different types of aggregate (basalt-limestone aggregate mixture and limestone aggregate). The stripping properties and moisture susceptibility characteristics of the samples have been evaluated by means of captured images and Nicholson Stripping Test (ASTM D 1664) as well as Modified Lottman Test (AASHTO T 283) respectively.The results indicated that both elastomeric (SBS) and plastomeric (EVA) polymer modification increased the resistance of asphalt mixtures to the detrimental effects of water. Moreover, it was found out that samples prepared with EVA PMB exhibits more moisture susceptibility compared to samples prepared with SBS PMB.