EBBR试验下沥青结合料低温性能评价指标

聚焦沥青结合料低温性能评价指标，基于流变学的弯曲梁流变仪试验、改进弯曲梁流变仪试验，分别分析了实际路面回收沥青、老化后的基质沥青、改性沥青低温流变性能规律；利用传统劲度模量及模量变化率指标展开了沥青的低温性能评价，提出了等效低温设计温度指标与温度差异值指标；在不同养护环境下进行模拟，利用低温等级损失指标对新制备、回收沥青展开了低温物理硬化影响因素研究；利用不同来源、不同品种沥青试验结果相互验证，从抗干扰能力、稳定性、评价准确度、直观性与指标获取难易程度等方面对上述指标进行分析，确立了4类指标对沥青低温性能的区分与评价能力。研究结果表明:回收沥青的实验室流变分析能够反映路面结构的低温抗裂水平，开裂严重路段沥青的模量明显高于其他路段，其数值差异可达130 MPa；新制备的SBS改性沥青与回收沥青低温加载规律一致性高，模量偏差低于15%，可有效搭建起实验室研究同实际路面病害处理需要的关系；传统指标数据稳定性偏弱，置信度仅为64.7%~82.3%，难以满足研究需要，温度差异值指标及低温等级损失指标在应用方面同样受到制约，对此仍需开展更多深入的研究。 

Low temperature performance evaluation indexes of asphalt binder based on EBBR test

Focusing on the evaluation indexes of the low temperature performance of asphalt binders, based on rheological bending beam rheometer (BBR) and extended bending beam rheometer (EBBR) tests, the low temperature rheological properties of the extracted asphalt, aging base asphalt and modified asphalt on actual pavements were analyzed. The low temperature performance evaluations of the asphalts were carried out using the traditional stiffness modulus and modulus changing rate. The equivalent low temperature design temperature index and the temperature difference value index were proposed. Simulations in different curing environments were conducted, and the influencing factors of physical hardening of newly prepared and extracted asphalt at low temperature were studied using low temperature grade loss index. Different sources and types of asphalt test results were used to verify each other, the above indexes were compared and analyzed in terms of anti-interference ability, stability, evaluation accuracy, intuitiveness, and difficulty in obtaining indexes. The abilities of four indexes in distinguishing and evaluating the low temperature performance of asphalt were established. Research results show that the laboratory rheological analysis of the extracted asphalt can reflect the low temperature crack resistance level of the pavement structure. The modulus of the asphalt in the severely cracked section is significantly higher than those in the other sections, and the value difference can reach about 130 MPa. The newly prepared SBS modified asphalt and the extracted asphalt have a high consistency at low temperature loads, and the modulus deviation is lower than 15%. It can effectively establishes the relationship between laboratory research and actual pavement disease treatment needs. The stability of traditional index data is weak, and the confidence is only 64.7%-82.3%, which is difficult to satisfy the research needs. The applications of temperature difference value index and low temperature grade loss index is also restricted, which still needs more in-depth research. 4 tabs, 10 figs, 32 refs.