In order to evaluate the aggregates contact characteristics of asphalt mixtures

an effective method of evaluating the aggregates contact characteristics of asphalt mixtures was proposed.The “contact couple” was established as a quantitative index of aggregates contact characteristics and 72 digital images of mixtures’ cut sections were obtained from the rutting test samples of AC20 HMA.Thus a statistical analysis of contact couples was made from the digital images.It is indicated that the contact couples are with normal distribution.Besides

the scale ratio of aggregates above 4.75mm (C>4.75)、the fine index (FI)and the segregation index(SI) were presented as main impact factors of aggregates contact characteristics.And further investigation of the relationship between impact factors and aggregates’ contact characteristics was carried out.It is revealed that the impact factors have good correlation with the contact couples

the interaction of impact factors is the main reason that influenced the aggregates contact characteristics

neither single factor nor dual factors can reflect the samples’ contact numbers exactly.