Identification of interfacial transition zone in asphalt concrete based on nano-scale metrology techniques

• Published in: Materials & design Vol. 129; pp. 91 - 102
• Main Authors: Zhu, Xingyi, Yuan, Ying, Li, Lihan, Du, Yuchuan, Li, Feng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 05.09.2017
• Subjects: Asphalt mixture; Energy dispersive X-ray spectrometer (EDS); Image processing technique; Interfacial transition zone; Nanoindentation; Asphalt mixture; Image processing technique; Energy dispersive X-ray spectrometer (EDS); Nanoindentation; Interfacial transition zone
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2017.05.015

Identifying the nature of the region where the mastic meets the aggregate surface (interfacial transition zone, ITZ) is very helpful in understanding some mechanisms that govern the fracture behavior of asphalt pavement. However, it is rather difficult to identify and study ITZ by bulk techniques. In this study, nano-scale metrology techniques, including nanoindentation (NI), field emission scanning electron microscope (FESEM), and energy dispersive X-ray spectrometer (EDS), were employed to explore the micromechanics, microstructure, and chemical properties of ITZ. Experimental results show that the ITZ exists in asphalt mixture and the thickness of ITZ is in the range from 5μm to 20μm. The modulus value of ITZ was found between that of the aggregate and the mastic. The microstructure of ITZ was observed to be more compacted than that of mastic. This study contributes significantly to the nano-scale characterization of ITZ in asphalt concrete, which can provide more realist inputs for the micromechanical models. [Display omitted] •A nano-scale method was proposed to identify the elastic modulus of interfacial transition zone in asphalt concrete.•It was found that the interfacial transition zone (ITZ) does exist in asphalt concrete and its thickness is about 5-20µm.•The elastic modulus of ITZ is between that of mastic and aggregates, which may result from a relatively compacted ITZ.