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

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.

Key words:ultra-thin friction course;cracking;indirect tensile asphalt cracking test;gradation;asphalt film thickness