Influence of fine aggregate content on low-temperature cracking of asphalt pavements

Low-temperature cracking occurs on some asphalt pavements even though the highperformance grade (PG) binders are applied in asphalt mixtures. It is neither realistic nor economic to solve the problems related to low-temperature cracking on asphalt pavements by purely using high PG binders. Other factors need to be investigated so that this type of distress can be further restrained. This study focuses on investigating the effect of fine aggregates on the low-temperature cracking on asphalt pavements. Low-temperature cracking was monitored and recorded on asphalt pavements in a cold, northeast area of China. Cores were drilled on the spots where low-temperature cracking occurred, and the aggregate gradations of the drilled cores were analyzed in the laboratory. An index called the Fine Aggregate Content Deviation Index (FACDI) was defined as the difference between the actual fine aggregate content and the lower limit of fine aggregate content in the designed aggregate gradation. A positive relation was observed between the FACDI and the cracking index of asphalt pavements. It was demonstrated that the fine aggregate content was another important factor that influences low-temperature cracking of asphalt pavement. The increase of fine aggregate content was found to jeopardize the resistance of asphalt mixture on low-temperature cracking. Based on FACDI, fine aggregate's contents in asphalt mixtures of asphalt layers can be recommended to ensure an asphalt pavement with good low-temperature performance.