基于SCB试验的沥青混合料低温性能评价指标研究

研究沥青混合料低温性能评价指标与路面开裂状况之间关系，是合理确定沥青混合料低温性能评价标准的重要依据。为解决传统小梁弯曲试验同现场开裂相关度不高的问题，针对现场不同裂缝间距段落的芯样，引入半圆弯曲试验（SCB）开展混合料低温断裂与抽提沥青BBR试验研究，建立沥青路面开裂间距与沥青混合料断裂能、断裂韧性、劲度模量等指标的关系。从SCB与BBR对比试验可得出结论：改进后的SCB试验能真实反映吉林地区沥青路面实际低温开裂状况；提出了寒区沥青路面低温开裂判定标准；并通过断裂能及断裂韧性等指标的对比分析，提出采用SCB试验的断裂能作为混合料低温性能的评价指标更为合理。研究成果丰富了沥青混合料低温性能评价方法，为完善沥青路面低温抗裂设计提供了技术支撑。

Evaluation Index of Low-temperature Asphalt Mixture Performance Based on Semi-circular Bending Test

The relationship between the low-temperature asphalt mixture performance evaluation index and pavement cracking is highly valued as it is an important basis for evaluating low-temperature asphalt mixture performance. In this study, the semi-circular bending (SCB) test was introduced for core samples with different cracking distances in the field along with the low-temperature asphalt cracking test and the bending beam rheometer (BBR) asphalt extraction test. Consequently, relationships were established between asphalt pavement cracking distance and fracture energy, fracture toughness, stiffness modulus, and other asphalt mixture indicators. The following conclusions can be drawn from the performed SCB and BBR tests:the improved SCB test can effectively reflect the actual low-temperature cracking of the asphalt pavement in Jilin Province; the criterion of low-temperature cracking of the asphalt pavement in the cold region is proposed through the comparative analysis of fracture energy, fracture toughness, and other indicators; furthermore, it is more reasonable to use the fracture energy of the SCB test as an evaluation index for low-temperature mixture performance. The research results enrich the low-temperature asphalt mixture performance evaluation method and provide technical support for improving the low-temperature cracking resistance design of asphalt pavements.