Impact of milling machine parameters on the properties of reclaimed asphalt pavement

Abstract

When using a high content of reclaimed asphalt pavement (RAP) in asphalt production, the RAP properties play a primary role in defining the performance of the new mixture. The RAP properties depend not only on the composition of the old pavement but also on the milling process. Here we performed a full-scale milling experiment at four jobsites. At each of them, three milling machine parameters were varied (moving speed, milling depth, and drum rotational speed), while everything else remained constant (pavement type, milling machine type, etc.). The results demonstrate that at high milling depth, increasing of milling machine moving speed generates larger RAP chunks. There is also evidence that milling in large chunks generates more filler. Finally, we found that the high temperature of milling picks does not age binder and that aggregate angularity does not correlate with milling parameters.