为研究巴西果效应下制备工艺对热再生沥青混合料沥青活性度（DoA）的影响，选取搅拌时间、新集料预热温度、沥青混合料回收料（RAP）粒径以及RAP和不同粒径集料加入试验室内搅拌锅的顺序等制备工艺参数为分析变量，在不添加再生剂的情况下将RAP与粒径相差较大的天然集料直接进行机械拌和、筛分并对筛分后的混合料进行沥青抽提试验，以测定其沥青含量并计算各再生沥青混合料的DoA。结果表明：热再生沥青混合料在任何制备工艺下均存在巴西果效应；在制备热再生沥青混合料时，搅拌时间、新集料预热温度、RAP粒径均与DoA呈正相关；相比细粒径RAP，选用粗粒径RAP制备得到的热再生沥青混合料的DoA由30%提高至60%；巴西果效应进一步解释了搅拌过程中小粒径RAP更多的分布于搅拌锅底层，与上层的大粒径新集料的接触碰撞几率减小而降低了沥青转移量，通过延长搅拌时间可减弱这一影响，但这种减弱有限。

In order to investigate the effect of manufacturing process on the Degree of binder Activity (DoA) of hot recycled asphalt mixture with regard to the Brazil-nut effect, the manufacturing process parameters such as mixing time, preheating temperature of virgin aggregates, reclaimed asphalt pavement (RAP) size and the adding orders of aggregates with different sizes into the laboratory mixing pot were selected as analysis variables. Without the addition of recycling agent, the mixtures produced from the RAP and the virgin aggregates with large particle size difference were directly mechanically mixed and screened, then the asphalt extraction test were conducted for the screened mixtures, and the binder content of each mixture in terms of different manufacturing process are determined. The results showed that when manufacturing hot - recycled asphalt mixture, the mixing time, preheating temperature of virgin aggregates and particle size of RAP indicated positively correlation with the DoA. Compared with the fine RAP, the DoA of hot recycled asphalt mixture prepared from middle RAP increased by 30% to 60%. The Brazil-nut effect further explained that the RAP with fine particle showed more distribution at the bottom of the mixing pot during the mixing process, and it reduced the contact and collision probability with the virgin aggregate with large particle size in the upper layer , which resulted in the decrease in the amount of binder transfer. This effect can be weakened by prolonging the mixing time, but this reduction is limited.