ABSTRACT

Low-temperature reversible aging is one of the most important forms of asphalt hardening, especially for cold regions. However, there are few researches about the influence of wax-based warm additive on the low-temperature reversible aging of asphalt, especially under non-isothermal conditioning. For this reason, simplified extended bending beam rheometer (Ex-BBR) test, non-isothermal rheological analysis and differential scanning calorimetry (DSC) test are performed on asphalt binders containing selected four kinds of commercial wax modifiers (Fischer-Tropschbased wax, linear aliphatic hydrocarbon-based wax, polyethylene-based wax, and fatty acid amides based wax). The results show that all commercial waxes used in this study will accelerate the degree of physical hardening in unaged asphalt binders. Compared with wax-based warm mix additive, oxidative aging has a greater impact on the low-temperature reversible aging properties of asphalt binder. Independent of cooling rate, the base asphalt has the highest phase angle value while the F–T wax modified asphalt has the lowest value. The crystallizable fraction increases with the decrease of cooling rate for both unaged and PAV aged sample. The magnitude of Ozawa exponent has the same order as grade loss for PAV aged sample. However, no obvious rule is observed for unaged asphalt binders.

摘要

低温可逆老化是沥青硬化最重要的形式之一，特别是在寒冷地区。然而，关于蜡基温添加剂对沥青低温可逆老化，尤其是在非等温条件下的影响的研究较少。为此，对含有四种商业蜡改性剂（费托基蜡、线性脂肪族烃基蜡、聚乙烯基蜡和脂肪酸酰胺基蜡）。结果表明，本研究中使用的所有商业蜡都将加速未老化沥青粘合剂的物理硬化程度。与蜡基温拌助剂相比，氧化老化对沥青结合料的低温可逆老化性能影响较大。与冷却速率无关，基础沥青的相角值最高，而 F-T 蜡改性沥青的相角值最低。对于未老化和 PAV 老化样品，可结晶分数随着冷却速率的降低而增加。Ozawa 指数的大小与 PAV 老化样品的等级损失具有相同的数量级。然而，对于未老化的沥青粘合剂，没有观察到明显的规律。Ozawa 指数的大小与 PAV 老化样品的等级损失具有相同的数量级。然而，对于未老化的沥青粘合剂，没有观察到明显的规律。Ozawa 指数的大小与 PAV 老化样品的等级损失具有相同的数量级。然而，对于未老化的沥青粘合剂，没有观察到明显的规律。