The use of the semi-circular bending method to assess the intermediate-temperature fracture toughness of asphalt concrete mixes with reclaimed asphalt shingles

Abstract

The article presents the results of crack-resistance tests of asphalt concrete mixtures with the addition of reclaimed asphalt shingles (RAS) performed using the semi-circular bending method (SCB). The aim of the work is to assess two aging conditions of the asphalt mixtures (short-term and long-term) on their fracture toughness. The flexibility index (FI), toughness index (TI) and, to a slightly lesser extent, cracking resistance index (CRI), turned out to be the most sensitive to the fracture toughness of asphalt mixtures subjected to various aging conditions. In the case of mixtures with the addition of RAS, it was observed that by changing the order of dosing the ingredients (adding RAS after new bitumen has been mixed with the aggregate), it was possible to reduce the negative impact of long-term aging on the resistance to cracking.

KEYWORDS:

• Semi-circular bending (SCB)
• reclaimed asphalt shingles (RAS)
• asphalt concrete (AC)
• fracture toughness
• flexibility index (FI)
• cracking resistance index (CRI)

Acknowledgements

The results of the research presented in this article were created as part of the dean's grant of the Faculty of Civil Engineering, Cracow University of Technology, entitled: 'Durability problems of HMA with the addition of recycled materials containing bitumen'.

Disclosure statement

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

Additional information

Funding

This work was supported by Politechnika Krakowska: [Grant Number Dean's grant of the Faculty of Civ. Eng. 2021-2022].

Notes on contributors

Piotr Zieliński

Piotr Zieliński is a Doctor of Sciences at the Cracow University of Technology. He has been working for the Department of Road, Railways and Traffic Engineering for 24 years. During his carrier he has been involved in various research and implementation projects (four of them sponsored by Polish Science Committee) concerning road pavement and their construction technologies. His main area of specialization is asphalt pavement with geosynthetics interlayer as well as recycling of asphalt pavement. He is the author of about 50 papers printed in scientific journals or presented at the numerous Polish and International Conferences.