Notched specimen cracking test: a novel method to directly measure low-temperature thermal stress of asphalt binder

ABSTRACT

A new method, the notched specimen cracking test (NSCT), is presented to directly measure the thermal stress and critical temperature of asphalt binders at low temperatures. The NSCT contains a notched specimen that contraction deformation is limited by special invar steel fixtures exposed to a continuous cooling temperature field provided by a programable environmental chamber. To simulate the actual thermal contraction state–strain level of asphalt pavement in the laboratory, the geometry of the binder specimen was carefully designed by theoretical computation based on the superposition principle. The preliminary test result shows that NSCT for evaluation of the potential cracking risk of modified or non-modified binders at low temperatures is reliable and easy to operate. The coefficient of variations of thermal stress results is at least 50% smaller than the traditional thermal cracking measurement method.

GRAPHICAL ABSTRACT

KEYWORDS:

• Asphalt binder
• thermal stress
• critical temperature
• low-temperature cracking
• asphalt grading
• materials test
• measurement

Acknowledgements

The authors thank Dr. Haibo Ding, M.S. Ting Luo and M.S. Jiangkang Zhang of Southwest Jiaotong University, China.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Disclaimer

The company names and commercial products appeared in this paper are for information only. It is not the intent for authors to promote or advocate any products. The statements do not necessarily reflect the viewpoints of agencies and governments.

Additional information

Funding

This work was supported by National Key Research and Development Program of China [grant number 2021YFB2600601], National Key Research and Development Program of China [grant number 2021YFB2600600], National Natural Science Foundation of China [grant number 51778139] and Postgraduate Research & Practice Innovation of Jiangsu Province [grant number KYCX21_0139].