Deagglomeration Analysis of RAP during the Hot Mixing Process

This study analyzed the deagglomeration phenomenon of reclaimed asphalt pavement (RAP) materials during hot mixing through the retained and passing percentages. The deagglomeration characteristics of integrated RAP were evaluated at different RAP preheating temperatures, mixing temperatures, and mixing times. Additionally, the deagglomeration features and compositions of single-sized RAP particles were assessed to determine the strong and weak agglomeration content. The results revealed that the white curve of RAP was substantially finer than the black curve due to the presence of agglomerated RAP particles. For integrated RAP, preheating temperature, mixing temperature, and mixing time influenced the deagglomeration of 10–20-mm RAP more than that of 5–10-mm RAP. The RAP preheating temperature had the greatest influence on the RAP deagglomeration, followed by mixing time and mixing temperature. After hot mixing, the retained percentage of particles larger than 13.2 mm increased in integrated 10–20-mm RAP, whereas the percentage of particles smaller than 13.2 mm decreased. The passing percentage after hot mixing was between the black and white curves. After hot mixing and extraction, single-sized RAP particles were composed mainly of initial-sized particles, secondary-sized particles, and smaller-sized particles. The strong and weak agglomeration contents were calculated based on whether the particles deagglomerated during the hot mixing process.