The performance of multi-layered bituminous pavements is affected by the bonding behavior of the interlayer. Quasi-static tests measuring the interlayer shear strength are mainly used for quality control. However, it is generally recognized that cyclic shear testing may allow determining interlayer parameters, which are more closely related to pavement performance. This chapter describes the research work carried out by the RILEM TC 272-PIM and specifically by the Task Group 3 “Pavement multilayer system”. The experimental activities consisted in an interlaboratory test with nine participating laboratories that aimed at investigating the interlayer behavior in terms of stiffness and resistance to repeated loading by using their available testing equipment. Testing involved direct shear and torque cyclic loading on double-layered specimens prepared in the laboratory. The chapter begins with a literature review, followed by the description of the interlaboratory test and by the presentation of the equipment and protocols adopted by the participating laboratories. The results showed that, besides temperature and frequency, laboratory-measured interlayer stiffness is mainly affected by the amplitude of the interlayer displacement and by the width of the gap imposed by the testing fixture. In this regard, a new parameter, the interlayer shear modulus, is proposed to analyze the output of different equipment. Regarding the interlayer resistance to cyclic loading, the results indicated that fatigue curves relating the applied interlayer displacement (or stress) and the number of cycles to failure can be obtained from both direct shear and torque tests. Finally, the chapter provides indications for harmonizing testing devices and protocols.
Canestrari, F., Attia, T., Di Benedetto, H., Graziani, A., Jaskula, P., Ferrotti, G., et al. (2025). Cyclic Characterization of Bituminous Interlayers. Berlino : Springer Science and Business Media B.V. [10.1007/978-3-031-88009-4_4].
Cyclic Characterization of Bituminous Interlayers
Sangiorgi C.;
2025
Abstract
The performance of multi-layered bituminous pavements is affected by the bonding behavior of the interlayer. Quasi-static tests measuring the interlayer shear strength are mainly used for quality control. However, it is generally recognized that cyclic shear testing may allow determining interlayer parameters, which are more closely related to pavement performance. This chapter describes the research work carried out by the RILEM TC 272-PIM and specifically by the Task Group 3 “Pavement multilayer system”. The experimental activities consisted in an interlaboratory test with nine participating laboratories that aimed at investigating the interlayer behavior in terms of stiffness and resistance to repeated loading by using their available testing equipment. Testing involved direct shear and torque cyclic loading on double-layered specimens prepared in the laboratory. The chapter begins with a literature review, followed by the description of the interlaboratory test and by the presentation of the equipment and protocols adopted by the participating laboratories. The results showed that, besides temperature and frequency, laboratory-measured interlayer stiffness is mainly affected by the amplitude of the interlayer displacement and by the width of the gap imposed by the testing fixture. In this regard, a new parameter, the interlayer shear modulus, is proposed to analyze the output of different equipment. Regarding the interlayer resistance to cyclic loading, the results indicated that fatigue curves relating the applied interlayer displacement (or stress) and the number of cycles to failure can be obtained from both direct shear and torque tests. Finally, the chapter provides indications for harmonizing testing devices and protocols.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
