厂拌热再生中老化沥青有效再生率的研究

摘要

为了研究厂拌热再生工艺中旧沥青混合料表层的老化沥青与新沥青及再生剂混溶机理,采用三聚氰胺作为新沥青示踪剂,通过扫描电镜测量厂拌热再生过程中旧集料表层老化沥青膜中示踪剂位置的变化参数,得到老化沥青有效再生率.基于对流传质理论分析了厂拌热再生中的预热温度、再生剂添加量及再生混合料拌和时间对老化沥青有效再生率的影响,并设计出能够良好模拟实际施工过程中老化沥青有效再生率的检测方法.试验结果表明:老化沥青预热温度升高、再生剂的添加以及再生沥青混合料拌和时间延长均可提高老化沥青的有效再生率.验证了其试验结果的可靠性,可为厂拌热再生中老化沥青的再生效果评价及工艺改进设计提供有效的理论依据.%In order to study the miscible mechanism of aged asphalt on the surface of the old aggregate and new asphalt under the influence of rejuvenator in central plant hot recycling technical conditions,the modified melamine in the new asphalt was added as the new tracer of the asphalt.The effective recycling ratio of aged asphalt was get by measuring the positon changes of the tracer in aged asphalt that on the cover surface of old aggregate with scanning electron microscopy (SEM).Based on convective mass transfer theory,the impact of preheating temperature of aged asphalt,the content of rejuvenator and the recycled asphalt mixing time in central plant hot recycling on effective recycling of aged asphalt was analyzed and a detection method which can simulate well the effective recycling of aged asphalt in actual construction process was proposed.The experimental results showed that increasing of preheating temperature of aged asphalt,the content of rejuvenator,the recycled asphalt mixing time could improve the effective recycling ratio of aged asphalt,the reliability was verified by the experiment.This study would provide some theoretical references for evaluation of recycling effect of aged asphalt and improvement of design and construction in central plant hot recycling of asphalt pavement.