Properties evaluation of cold mix asphalt based on compaction energy and mixture gradation

Abstract

Mix design for cold mix asphalt as a surface course has several factors to be considered, such as the traffic level and environmental condition. The compaction energy in mix design is related to expected traffic level. The choice of aggregate gradation is affected by the environment condition. Generally, there are two types of cold asphalt mixture, open graded and dense graded. The purpose of this study is to investigate the properties of cold mix asphalt surface course considering the compaction energy and aggregate gradation factors by laboratory experiments. The trial specimens were prepared with five different cationic emulsion bitumen contents for each type of mixture gradation at various compaction energy using Marshall compactor machine. The stability and volumetric properties of these specimens were measured by Marshall Test and then compared to the specified values. If the pavement is designed properly, dense graded cold mix asphalt could be used for surface course for medium and light traffic, while open graded mixture has potential application for heavy traffic. Over compaction could cause a greatly increased stiffness of mixture, which potentially lead to crack. Cold mix asphalt with different type of gradation needs different compaction energy to reach the best properties of mixture.