SBS改性沥青抽提回收影响因素及改进方案

Influential factors and improvement of extraction and recovery of SBS modified asphalt

分析国内目前使用最广泛的离心抽提法和阿布森回收法的不足及其产生原因．针对SBS改性沥青的抽提回收，设计不同的对比试验，研究三氯乙烯、矿粉及温度等关键影响因素对回收SBS改性沥青性能的影响程度与规律．在现有试验方法的基础上，针对其不足之处以及不同的影响因素，制定相应的补充改进措施：针对矿粉的干扰，当不具备高速离心分离及压力过滤设备时，通过将抽提所得混合液自然沉淀24h以上，然后取上层混合溶液进行回收试验，以消除矿粉影响；针对三氯乙烯的影响，调整阿布森试验温度不高于140℃，可以不使用保护气，直至不再有冷凝的三氯乙烯产生时，取出混合液并置于宽口径容器中，在烘箱内130～140℃搅拌蒸发2h，然后调整温度至160—170℃继续搅拌蒸发2h，以消除三氯乙烯的影响．从而提高试验精度，准确评价抽提回收SBS改性沥青性能．

The centrifugal extraction method and Abson recovery method are most commonly used at home and abroad in recent years. The defects and corresponding possible reasons for these two methods are analyzed. Considering the characters of SBS （styrene-butadience-styrene copolymer） modified asphalt mixtures, several different tests were designed and carried out to verify influences of some key factors such as trichloroethylene, mineral filler, temperature on the reclaimed SBS modified asphalt during the process of extraction and recovery experiments. And the corresponding solutions for different influencing factors were presented so that the performances of SBS modified asphalt in SBS modified asphalt mixture can be evaluated accurately. To decrease the adverse effects from residual mineral filler, when there are no equipments for high-speed centrifugal separation and pressure filtration, the upper part of the extracting solution from the extraction equipment is adopted for Abson recovery experiment after natural sediment for more than 24 hours. To decrease the adverse effects from residual trichloroethylene and high temperature, the temperature of Abson recovery experiment can be reduced to less than 140 ℃, and the protection gas can be removed, when there is no condensing liquid trichloroethylene coming out from the end orifice of the condenser tube, the solution in the Abson flask can be poured into a vessel with wider caliber to be evaporated with incessant churning for 2 hours at the temperature of 130 to 140 ℃, and then evaporated with incessant churning for another 2 hours at the temperature of 160 to 170℃in the oven.