Interfacial thickness and interaction between asphalt and mineral fillers

In order to improve the road performance of asphalt mixture, interfacial structure and interaction of asphalt mastic which is the most important component of asphalt mixture were studied. The interface thicknesses of asphalt mastics were calculated by the specific heat value changes in glass transition. The critical volume fractions of asphalt mastics were determined for each asphalt-filler combination using a simple two-point projection technique based on the reciprocal relative creep compliance. The interface interaction parameter was proposed based on modified Palierne emulsion model, and its effect factors were analyzed. The results show that the interface layer between asphalt and filler is nanoscale, which becomes thicker with the increasing of filler volume fraction, and granite filler has the thickest interface layer. The higher the temperature is, the smaller the critical volume fraction is. When the temperature is lower than 45 °C, the critical volume fractions ranking of asphalt mastics is as follows: limestone > andesite > granite. When the temperature is higher than 45 °C, the distinction of critical volume fraction is not obvious. B value can represent interaction between asphalt and filler exactly. The interface interaction ranking between asphalt and different fillers is as follows: granite > andesite > limestone. The higher the temperature is (or the more fine the filler is), the stronger the interface interaction is.