Bitumen Selection Approach Assessing Its Resistance to Low Temperature Cracking

Judita Gražulytė, Audrius Vaitkus, Igoris Kravcovas

Last modified: 2017-02-28


Low temperature cracking or thermal cracking is one of the most important distress in asphalt pavements located in cold regions. The development of it results in higher pavement roughness, faster pavement deterioration and requires millions of euros of repair and maintenance annually. The proper bitumen selection for asphalt mixture production restricts the formation of low temperature cracking. However, most designers do not consider bitumen susceptibility to low temperature cracking, because it needs to carry out additional laboratory tests and it requires supplementary cost and time in asphalt mixture selection. Consequently, this paper is focused on approach how to select bitumen assessing its resistance to low temperature cracking in easy and fast way. First, 11 bitumens of which 6 bitumens were polymer modified bitumens, were investigated. The critical temperature of bitumen, below which low temperature cracking occurs in the pavement, was calculated based on bending beam rheometer (BBR) experimental data by American Association of State and Highway Transportation (AASHTO) specifications. The performance grades (PG) low limits of bitumens were also determined using 3 °C step. The performance grade low limit varied from -16 °C up to -28 °C. Four polymer modified bitumens were not prone to low temperature cracking even at -28 °C temperature. Second, Lithuania was divided into 3 zones according to minimum pavement temperature. It gave possibility for designers to choose bitumen assessing its resistance to low temperature cracking based on road location. The implementation of this procedure will restrict low temperature cracking in asphalt pavements and will result in significant lower maintenance cost.


bitumen; thermal cracking; low temperature cracking; bending beam rheometer (BBR); critical temperature; performance grade

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