基于间接拉伸开裂方法评价超薄磨耗层混合料抗裂性能

Evaluation of Cracking Performance of Ultra-Thin Friction Course Mixture Based on Indirect Tensile Asphalt Cracking Test

摘要:

通过间接拉伸开裂（IDEAL-CT）试验方法，研究了不同级配及油石比条件下超薄磨耗层混合料的抗裂性能。结果显示，级配变密会导致混合料整体强度上升，抗变形能力下降，同时会加快裂缝扩展速度，混合料抗裂性能下降。油石比的增加会使混合料抗变形能力提升，延缓裂缝扩展速度，使得混合料抗裂性能增强。皮尔逊相关性分析结果表明，随着超薄磨耗层混合料的孔隙率和沥青膜厚度的增加，混合料整体强度降低，抗变形能力提升，裂缝开裂速度下降，混合料整体抗裂性能增强，因而超薄磨耗层混合料设计过程中可通过提升孔隙率和沥青膜厚度来增强混合料的抗裂性能。对于IDEAL-CT试验指标，断裂能不适用于评价超薄磨耗层混合料抗裂性能。

Abstract:

This paper studied the cracking performance of ultra-thin friction course mixtures with different gradations and asphalt content by utilizing indirect tensile asphalt cracking test （IDEAL-CT）. The results show that denser gradation would cause a higher mixture strength and a worse resistance to deformation， as well as a faster crack propagation， indicating a worse cracking resistance of mixture. With the increment of asphalt content， the deformation resistance of mixtures was enhanced and the crack propagation was postponed， which revealed that the cracking resistance of mixture was enhanced. The Pearson correlation analysis indicates that with the increment of air voids and asphalt film thickness， the strength of mixture decrease， the resistance to deformation is enhanced and the crack propagation is decreased， resulting in a better cracking resistance performance. Therefore， the air void and asphalt film thickness are recommended to be raised to improve the cracking resistance performance of mixture during ultra-thin friction course design. For the indicators of IDEAL-CT test， the fracture energy is not appropriate to evaluation of the cracking resistance performance of ultra-thin friction course mixture.